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fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fs-verity: remove filenames from file comments Embedding the file path inside kernel source code files isn't particularly useful as often files are moved around and the paths become incorrect. checkpatch.pl warns about this since v5.10-rc1. Acked-by: Luca Boccassi <luca.boccassi@microsoft.com> Link: https://lore.kernel.org/r/20201113211918.71883-2-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-11-13 13:19:15 -08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: use shash API instead of ahash API The "ahash" API, like the other scatterlist-based crypto APIs such as "skcipher", comes with some well-known limitations. First, it can't easily be used with vmalloc addresses. Second, the request struct can't be allocated on the stack. This adds complexity and a possible failure point that needs to be worked around, e.g. using a mempool. The only benefit of ahash over "shash" is that ahash is needed to access traditional memory-to-memory crypto accelerators, i.e. drivers/crypto/. However, this style of crypto acceleration has largely fallen out of favor and been superseded by CPU-based acceleration or inline crypto engines. Also, ahash needs to be used asynchronously to take full advantage of such hardware, but fs/verity/ has never done this. On all systems that aren't actually using one of these ahash-only crypto accelerators, ahash just adds unnecessary overhead as it sits between the user and the underlying shash algorithms. Also, XFS is planned to cache fsverity Merkle tree blocks in the existing XFS buffer cache. As a result, it will be possible for a single Merkle tree block to be split across discontiguous pages (https://lore.kernel.org/r/20230405233753.GU3223426@dread.disaster.area). This data will need to be hashed. It is easiest to work with a vmapped address in this case. However, ahash is incompatible with this. Therefore, let's convert fs/verity/ from ahash to shash. This simplifies the code, and it should also slightly improve performance for everyone who wasn't actually using one of these ahash-only crypto accelerators, i.e. almost everyone (or maybe even everyone)! Link: https://lore.kernel.org/r/20230516052306.99600-1-ebiggers@kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-05-15 22:12:16 -07:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fsverity: explicitly check for buffer overflow in build_merkle_tree() The new Merkle tree construction algorithm is a bit fragile in that it may overflow the 'root_hash' array if the tree actually generated does not match the calculated tree parameters. This should never happen unless there is a filesystem bug that allows the file size to change despite deny_write_access(), or a bug in the Merkle tree logic itself. Regardless, it's fairly easy to check for buffer overflow here, so let's do so. This is a robustness improvement only; this case is not currently known to be reachable. I've added a Fixes tag anyway, since I recommend that this be included in kernels that have the mentioned commit. Fixes: 56124d6c87fd ("fsverity: support enabling with tree block size < PAGE_SIZE") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230328041505.110162-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-03-27 21:15:05 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fs-verity: implement readahead for FS_IOC_ENABLE_VERITY When it builds the first level of the Merkle tree, FS_IOC_ENABLE_VERITY sequentially reads each page of the file using read_mapping_page(). This works fine if the file's data is already in pagecache, which should normally be the case, since this ioctl is normally used immediately after writing out the file. But in any other case this implementation performs very poorly, since only one page is read at a time. Fix this by implementing readahead using the functions from mm/readahead.c. This improves performance in the uncached case by about 20x, as seen in the following benchmarks done on a 250MB file (on x86_64 with SHA-NI): FS_IOC_ENABLE_VERITY uncached (before) 3.299s FS_IOC_ENABLE_VERITY uncached (after) 0.160s FS_IOC_ENABLE_VERITY cached 0.147s sha256sum uncached 0.191s sha256sum cached 0.145s Note: we could instead switch to kernel_read(). But that would mean we'd no longer be hashing the data directly from the pagecache, which is a nice optimization of its own. And using kernel_read() would require allocating another temporary buffer, hashing the data and tree pages separately, and explicitly zero-padding the last page -- so it wouldn't really be any simpler than direct pagecache access, at least for now. Link: https://lore.kernel.org/r/20200106205410.136707-1-ebiggers@kernel.org Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-01-06 12:54:10 -08:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fsverity: use shash API instead of ahash API The "ahash" API, like the other scatterlist-based crypto APIs such as "skcipher", comes with some well-known limitations. First, it can't easily be used with vmalloc addresses. Second, the request struct can't be allocated on the stack. This adds complexity and a possible failure point that needs to be worked around, e.g. using a mempool. The only benefit of ahash over "shash" is that ahash is needed to access traditional memory-to-memory crypto accelerators, i.e. drivers/crypto/. However, this style of crypto acceleration has largely fallen out of favor and been superseded by CPU-based acceleration or inline crypto engines. Also, ahash needs to be used asynchronously to take full advantage of such hardware, but fs/verity/ has never done this. On all systems that aren't actually using one of these ahash-only crypto accelerators, ahash just adds unnecessary overhead as it sits between the user and the underlying shash algorithms. Also, XFS is planned to cache fsverity Merkle tree blocks in the existing XFS buffer cache. As a result, it will be possible for a single Merkle tree block to be split across discontiguous pages (https://lore.kernel.org/r/20230405233753.GU3223426@dread.disaster.area). This data will need to be hashed. It is easiest to work with a vmapped address in this case. However, ahash is incompatible with this. Therefore, let's convert fs/verity/ from ahash to shash. This simplifies the code, and it should also slightly improve performance for everyone who wasn't actually using one of these ahash-only crypto accelerators, i.e. almost everyone (or maybe even everyone)! Link: https://lore.kernel.org/r/20230516052306.99600-1-ebiggers@kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-05-15 22:12:16 -07:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: explicitly check for buffer overflow in build_merkle_tree() The new Merkle tree construction algorithm is a bit fragile in that it may overflow the 'root_hash' array if the tree actually generated does not match the calculated tree parameters. This should never happen unless there is a filesystem bug that allows the file size to change despite deny_write_access(), or a bug in the Merkle tree logic itself. Regardless, it's fairly easy to check for buffer overflow here, so let's do so. This is a robustness improvement only; this case is not currently known to be reachable. I've added a Fixes tag anyway, since I recommend that this be included in kernels that have the mentioned commit. Fixes: 56124d6c87fd ("fsverity: support enabling with tree block size < PAGE_SIZE") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230328041505.110162-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-03-27 21:15:05 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: use shash API instead of ahash API The "ahash" API, like the other scatterlist-based crypto APIs such as "skcipher", comes with some well-known limitations. First, it can't easily be used with vmalloc addresses. Second, the request struct can't be allocated on the stack. This adds complexity and a possible failure point that needs to be worked around, e.g. using a mempool. The only benefit of ahash over "shash" is that ahash is needed to access traditional memory-to-memory crypto accelerators, i.e. drivers/crypto/. However, this style of crypto acceleration has largely fallen out of favor and been superseded by CPU-based acceleration or inline crypto engines. Also, ahash needs to be used asynchronously to take full advantage of such hardware, but fs/verity/ has never done this. On all systems that aren't actually using one of these ahash-only crypto accelerators, ahash just adds unnecessary overhead as it sits between the user and the underlying shash algorithms. Also, XFS is planned to cache fsverity Merkle tree blocks in the existing XFS buffer cache. As a result, it will be possible for a single Merkle tree block to be split across discontiguous pages (https://lore.kernel.org/r/20230405233753.GU3223426@dread.disaster.area). This data will need to be hashed. It is easiest to work with a vmapped address in this case. However, ahash is incompatible with this. Therefore, let's convert fs/verity/ from ahash to shash. This simplifies the code, and it should also slightly improve performance for everyone who wasn't actually using one of these ahash-only crypto accelerators, i.e. almost everyone (or maybe even everyone)! Link: https://lore.kernel.org/r/20230516052306.99600-1-ebiggers@kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-05-15 22:12:16 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fs-verity: implement readahead for FS_IOC_ENABLE_VERITY When it builds the first level of the Merkle tree, FS_IOC_ENABLE_VERITY sequentially reads each page of the file using read_mapping_page(). This works fine if the file's data is already in pagecache, which should normally be the case, since this ioctl is normally used immediately after writing out the file. But in any other case this implementation performs very poorly, since only one page is read at a time. Fix this by implementing readahead using the functions from mm/readahead.c. This improves performance in the uncached case by about 20x, as seen in the following benchmarks done on a 250MB file (on x86_64 with SHA-NI): FS_IOC_ENABLE_VERITY uncached (before) 3.299s FS_IOC_ENABLE_VERITY uncached (after) 0.160s FS_IOC_ENABLE_VERITY cached 0.147s sha256sum uncached 0.191s sha256sum cached 0.145s Note: we could instead switch to kernel_read(). But that would mean we'd no longer be hashing the data directly from the pagecache, which is a nice optimization of its own. And using kernel_read() would require allocating another temporary buffer, hashing the data and tree pages separately, and explicitly zero-padding the last page -- so it wouldn't really be any simpler than direct pagecache access, at least for now. Link: https://lore.kernel.org/r/20200106205410.136707-1-ebiggers@kernel.org Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-01-06 12:54:10 -08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fs-verity: implement readahead for FS_IOC_ENABLE_VERITY When it builds the first level of the Merkle tree, FS_IOC_ENABLE_VERITY sequentially reads each page of the file using read_mapping_page(). This works fine if the file's data is already in pagecache, which should normally be the case, since this ioctl is normally used immediately after writing out the file. But in any other case this implementation performs very poorly, since only one page is read at a time. Fix this by implementing readahead using the functions from mm/readahead.c. This improves performance in the uncached case by about 20x, as seen in the following benchmarks done on a 250MB file (on x86_64 with SHA-NI): FS_IOC_ENABLE_VERITY uncached (before) 3.299s FS_IOC_ENABLE_VERITY uncached (after) 0.160s FS_IOC_ENABLE_VERITY cached 0.147s sha256sum uncached 0.191s sha256sum cached 0.145s Note: we could instead switch to kernel_read(). But that would mean we'd no longer be hashing the data directly from the pagecache, which is a nice optimization of its own. And using kernel_read() would require allocating another temporary buffer, hashing the data and tree pages separately, and explicitly zero-padding the last page -- so it wouldn't really be any simpler than direct pagecache access, at least for now. Link: https://lore.kernel.org/r/20200106205410.136707-1-ebiggers@kernel.org Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-01-06 12:54:10 -08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fs-verity: implement readahead for FS_IOC_ENABLE_VERITY When it builds the first level of the Merkle tree, FS_IOC_ENABLE_VERITY sequentially reads each page of the file using read_mapping_page(). This works fine if the file's data is already in pagecache, which should normally be the case, since this ioctl is normally used immediately after writing out the file. But in any other case this implementation performs very poorly, since only one page is read at a time. Fix this by implementing readahead using the functions from mm/readahead.c. This improves performance in the uncached case by about 20x, as seen in the following benchmarks done on a 250MB file (on x86_64 with SHA-NI): FS_IOC_ENABLE_VERITY uncached (before) 3.299s FS_IOC_ENABLE_VERITY uncached (after) 0.160s FS_IOC_ENABLE_VERITY cached 0.147s sha256sum uncached 0.191s sha256sum cached 0.145s Note: we could instead switch to kernel_read(). But that would mean we'd no longer be hashing the data directly from the pagecache, which is a nice optimization of its own. And using kernel_read() would require allocating another temporary buffer, hashing the data and tree pages separately, and explicitly zero-padding the last page -- so it wouldn't really be any simpler than direct pagecache access, at least for now. Link: https://lore.kernel.org/r/20200106205410.136707-1-ebiggers@kernel.org Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-01-06 12:54:10 -08:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fsverity: explicitly check for buffer overflow in build_merkle_tree() The new Merkle tree construction algorithm is a bit fragile in that it may overflow the 'root_hash' array if the tree actually generated does not match the calculated tree parameters. This should never happen unless there is a filesystem bug that allows the file size to change despite deny_write_access(), or a bug in the Merkle tree logic itself. Regardless, it's fairly easy to check for buffer overflow here, so let's do so. This is a robustness improvement only; this case is not currently known to be reachable. I've added a Fixes tag anyway, since I recommend that this be included in kernels that have the mentioned commit. Fixes: 56124d6c87fd ("fsverity: support enabling with tree block size < PAGE_SIZE") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230328041505.110162-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-03-27 21:15:05 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fsverity: use shash API instead of ahash API The "ahash" API, like the other scatterlist-based crypto APIs such as "skcipher", comes with some well-known limitations. First, it can't easily be used with vmalloc addresses. Second, the request struct can't be allocated on the stack. This adds complexity and a possible failure point that needs to be worked around, e.g. using a mempool. The only benefit of ahash over "shash" is that ahash is needed to access traditional memory-to-memory crypto accelerators, i.e. drivers/crypto/. However, this style of crypto acceleration has largely fallen out of favor and been superseded by CPU-based acceleration or inline crypto engines. Also, ahash needs to be used asynchronously to take full advantage of such hardware, but fs/verity/ has never done this. On all systems that aren't actually using one of these ahash-only crypto accelerators, ahash just adds unnecessary overhead as it sits between the user and the underlying shash algorithms. Also, XFS is planned to cache fsverity Merkle tree blocks in the existing XFS buffer cache. As a result, it will be possible for a single Merkle tree block to be split across discontiguous pages (https://lore.kernel.org/r/20230405233753.GU3223426@dread.disaster.area). This data will need to be hashed. It is easiest to work with a vmapped address in this case. However, ahash is incompatible with this. Therefore, let's convert fs/verity/ from ahash to shash. This simplifies the code, and it should also slightly improve performance for everyone who wasn't actually using one of these ahash-only crypto accelerators, i.e. almost everyone (or maybe even everyone)! Link: https://lore.kernel.org/r/20230516052306.99600-1-ebiggers@kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-05-15 22:12:16 -07:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fsverity: use shash API instead of ahash API The "ahash" API, like the other scatterlist-based crypto APIs such as "skcipher", comes with some well-known limitations. First, it can't easily be used with vmalloc addresses. Second, the request struct can't be allocated on the stack. This adds complexity and a possible failure point that needs to be worked around, e.g. using a mempool. The only benefit of ahash over "shash" is that ahash is needed to access traditional memory-to-memory crypto accelerators, i.e. drivers/crypto/. However, this style of crypto acceleration has largely fallen out of favor and been superseded by CPU-based acceleration or inline crypto engines. Also, ahash needs to be used asynchronously to take full advantage of such hardware, but fs/verity/ has never done this. On all systems that aren't actually using one of these ahash-only crypto accelerators, ahash just adds unnecessary overhead as it sits between the user and the underlying shash algorithms. Also, XFS is planned to cache fsverity Merkle tree blocks in the existing XFS buffer cache. As a result, it will be possible for a single Merkle tree block to be split across discontiguous pages (https://lore.kernel.org/r/20230405233753.GU3223426@dread.disaster.area). This data will need to be hashed. It is easiest to work with a vmapped address in this case. However, ahash is incompatible with this. Therefore, let's convert fs/verity/ from ahash to shash. This simplifies the code, and it should also slightly improve performance for everyone who wasn't actually using one of these ahash-only crypto accelerators, i.e. almost everyone (or maybe even everyone)! Link: https://lore.kernel.org/r/20230516052306.99600-1-ebiggers@kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-05-15 22:12:16 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fsverity: use shash API instead of ahash API The "ahash" API, like the other scatterlist-based crypto APIs such as "skcipher", comes with some well-known limitations. First, it can't easily be used with vmalloc addresses. Second, the request struct can't be allocated on the stack. This adds complexity and a possible failure point that needs to be worked around, e.g. using a mempool. The only benefit of ahash over "shash" is that ahash is needed to access traditional memory-to-memory crypto accelerators, i.e. drivers/crypto/. However, this style of crypto acceleration has largely fallen out of favor and been superseded by CPU-based acceleration or inline crypto engines. Also, ahash needs to be used asynchronously to take full advantage of such hardware, but fs/verity/ has never done this. On all systems that aren't actually using one of these ahash-only crypto accelerators, ahash just adds unnecessary overhead as it sits between the user and the underlying shash algorithms. Also, XFS is planned to cache fsverity Merkle tree blocks in the existing XFS buffer cache. As a result, it will be possible for a single Merkle tree block to be split across discontiguous pages (https://lore.kernel.org/r/20230405233753.GU3223426@dread.disaster.area). This data will need to be hashed. It is easiest to work with a vmapped address in this case. However, ahash is incompatible with this. Therefore, let's convert fs/verity/ from ahash to shash. This simplifies the code, and it should also slightly improve performance for everyone who wasn't actually using one of these ahash-only crypto accelerators, i.e. almost everyone (or maybe even everyone)! Link: https://lore.kernel.org/r/20230516052306.99600-1-ebiggers@kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-05-15 22:12:16 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fsverity: use WARN_ON_ONCE instead of WARN_ON As per Linus's suggestion (https://lore.kernel.org/r/CAHk-=whefxRGyNGzCzG6BVeM=5vnvgb-XhSeFJVxJyAxAF8XRA@mail.gmail.com), use WARN_ON_ONCE instead of WARN_ON. This barely adds any extra overhead, and it makes it so that if any of these ever becomes reachable (they shouldn't, but that's the point), the logs can't be flooded. Link: https://lore.kernel.org/r/20230406181542.38894-1-ebiggers@kernel.org Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-03-27 21:03:26 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fs-verity: Use struct_size() helper in enable_verity() Follow the best practice for allocating a variable-sized structure. Signed-off-by: Zhang Jianhua <chris.zjh@huawei.com> [ebiggers: adjusted commit message] Signed-off-by: Eric Biggers <ebiggers@google.com> Link: https://lore.kernel.org/r/20220519022450.2434483-1-chris.zjh@huawei.com
2022-05-19 10:24:50 +08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fs-verity: use u64_to_user_ptr() <linux/kernel.h> already provides a macro u64_to_user_ptr(). Use it instead of open-coding the two casts. No change in behavior. Link: https://lore.kernel.org/r/20191231175408.20524-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-12-31 11:54:08 -06:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: improve documentation for builtin signature support fsverity builtin signatures (CONFIG_FS_VERITY_BUILTIN_SIGNATURES) aren't the only way to do signatures with fsverity, and they have some major limitations. Yet, more users have tried to use them, e.g. recently by https://github.com/ostreedev/ostree/pull/2640. In most cases this seems to be because users aren't sufficiently familiar with the limitations of this feature and what the alternatives are. Therefore, make some updates to the documentation to try to clarify the properties of this feature and nudge users in the right direction. Note that the Integrity Policy Enforcement (IPE) LSM, which is not yet upstream, is planned to use the builtin signatures. (This differs from IMA, which uses its own signature mechanism.) For that reason, my earlier patch "fsverity: mark builtin signatures as deprecated" (https://lore.kernel.org/r/20221208033548.122704-1-ebiggers@kernel.org), which marked builtin signatures as "deprecated", was controversial. This patch therefore stops short of marking the feature as deprecated. I've also revised the language to focus on better explaining the feature and what its alternatives are. Link: https://lore.kernel.org/r/20230620041937.5809-1-ebiggers@kernel.org Reviewed-by: Colin Walters <walters@verbum.org> Reviewed-by: Luca Boccassi <bluca@debian.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-06-19 21:19:37 -07:00
fs-verity: support builtin file signatures To meet some users' needs, add optional support for having fs-verity handle a portion of the authentication policy in the kernel. An ".fs-verity" keyring is created to which X.509 certificates can be added; then a sysctl 'fs.verity.require_signatures' can be set to cause the kernel to enforce that all fs-verity files contain a signature of their file measurement by a key in this keyring. See the "Built-in signature verification" section of Documentation/filesystems/fsverity.rst for the full documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:23 -07:00
fs-verity: use u64_to_user_ptr() <linux/kernel.h> already provides a macro u64_to_user_ptr(). Use it instead of open-coding the two casts. No change in behavior. Link: https://lore.kernel.org/r/20191231175408.20524-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-12-31 11:54:08 -06:00
fs-verity: support builtin file signatures To meet some users' needs, add optional support for having fs-verity handle a portion of the authentication policy in the kernel. An ".fs-verity" keyring is created to which X.509 certificates can be added; then a sysctl 'fs.verity.require_signatures' can be set to cause the kernel to enforce that all fs-verity files contain a signature of their file measurement by a key in this keyring. See the "Built-in signature verification" section of Documentation/filesystems/fsverity.rst for the full documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:23 -07:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fs-verity: implement readahead for FS_IOC_ENABLE_VERITY When it builds the first level of the Merkle tree, FS_IOC_ENABLE_VERITY sequentially reads each page of the file using read_mapping_page(). This works fine if the file's data is already in pagecache, which should normally be the case, since this ioctl is normally used immediately after writing out the file. But in any other case this implementation performs very poorly, since only one page is read at a time. Fix this by implementing readahead using the functions from mm/readahead.c. This improves performance in the uncached case by about 20x, as seen in the following benchmarks done on a 250MB file (on x86_64 with SHA-NI): FS_IOC_ENABLE_VERITY uncached (before) 3.299s FS_IOC_ENABLE_VERITY uncached (after) 0.160s FS_IOC_ENABLE_VERITY cached 0.147s sha256sum uncached 0.191s sha256sum cached 0.145s Note: we could instead switch to kernel_read(). But that would mean we'd no longer be hashing the data directly from the pagecache, which is a nice optimization of its own. And using kernel_read() would require allocating another temporary buffer, hashing the data and tree pages separately, and explicitly zero-padding the last page -- so it wouldn't really be any simpler than direct pagecache access, at least for now. Link: https://lore.kernel.org/r/20200106205410.136707-1-ebiggers@kernel.org Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-01-06 12:54:10 -08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fs-verity: remove unused parameter desc_size in fsverity_create_info() The parameter desc_size in fsverity_create_info() is useless and it is not referenced anywhere. The greatest meaning of desc_size here is to indecate the size of struct fsverity_descriptor and futher calculate the size of signature. However, the desc->sig_size can do it also and it is indeed, so remove it. Therefore, it is no need to acquire desc_size by fsverity_get_descriptor() in ensure_verity_info(), so remove the parameter desc_ret in fsverity_get_descriptor() too. Signed-off-by: Zhang Jianhua <chris.zjh@huawei.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Link: https://lore.kernel.org/r/20220518132256.2297655-1-chris.zjh@huawei.com
2022-05-18 21:22:56 +08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: use WARN_ON_ONCE instead of WARN_ON As per Linus's suggestion (https://lore.kernel.org/r/CAHk-=whefxRGyNGzCzG6BVeM=5vnvgb-XhSeFJVxJyAxAF8XRA@mail.gmail.com), use WARN_ON_ONCE instead of WARN_ON. This barely adds any extra overhead, and it makes it so that if any of these ever becomes reachable (they shouldn't, but that's the point), the logs can't be flooded. Link: https://lore.kernel.org/r/20230406181542.38894-1-ebiggers@kernel.org Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-03-27 21:03:26 -07:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fs-verity: fix all kerneldoc warnings Fix all kerneldoc warnings in fs/verity/ and include/linux/fsverity.h. Most of these were due to missing documentation for function parameters. Detected with: scripts/kernel-doc -v -none fs/verity/*.{c,h} include/linux/fsverity.h This cleanup makes it possible to check new patches for kerneldoc warnings without having to filter out all the existing ones. Link: https://lore.kernel.org/r/20200511192118.71427-2-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-05-11 12:21:17 -07:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: support enabling with tree block size < PAGE_SIZE Make FS_IOC_ENABLE_VERITY support values of fsverity_enable_arg::block_size other than PAGE_SIZE. To make this possible, rework build_merkle_tree(), which was reading data and hash pages from the file and assuming that they were the same thing as "blocks". For reading the data blocks, just replace the direct pagecache access with __kernel_read(), to naturally read one block at a time. (A disadvantage of the above is that we lose the two optimizations of hashing the pagecache pages in-place and forcing the maximum readahead. That shouldn't be very important, though.) The hash block reads are a bit more difficult to handle, as the only way to do them is through fsverity_operations::read_merkle_tree_page(). Instead, let's switch to the single-pass tree construction algorithm that fsverity-utils uses. This eliminates the need to read back any hash blocks while the tree is being built, at the small cost of an extra block-sized memory buffer per Merkle tree level. This is probably what I should have done originally. Taken together, the above two changes result in page-size independent code that is also a bit simpler than what we had before. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com> Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Link: https://lore.kernel.org/r/20221223203638.41293-8-ebiggers@kernel.org
2022-12-23 12:36:34 -08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
treewide: Use sizeof_field() macro Replace all the occurrences of FIELD_SIZEOF() with sizeof_field() except at places where these are defined. Later patches will remove the unused definition of FIELD_SIZEOF(). This patch is generated using following script: EXCLUDE_FILES="include/linux/stddef.h|include/linux/kernel.h" git grep -l -e "\bFIELD_SIZEOF\b" | while read file; do if [[ "$file" =~ $EXCLUDE_FILES ]]; then continue fi sed -i -e 's/\bFIELD_SIZEOF\b/sizeof_field/g' $file; done Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com> Link: https://lore.kernel.org/r/20190924105839.110713-3-pankaj.laxminarayan.bharadiya@intel.com Co-developed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: David Miller <davem@davemloft.net> # for net
2019-12-09 10:31:43 -08:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fs-verity: support builtin file signatures To meet some users' needs, add optional support for having fs-verity handle a portion of the authentication policy in the kernel. An ".fs-verity" keyring is created to which X.509 certificates can be added; then a sysctl 'fs.verity.require_signatures' can be set to cause the kernel to enforce that all fs-verity files contain a signature of their file measurement by a key in this keyring. See the "Built-in signature verification" section of Documentation/filesystems/fsverity.rst for the full documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:23 -07:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fs: add file and path permissions helpers Add two simple helpers to check permissions on a file and path respectively and convert over some callers. It simplifies quite a few codepaths and also reduces the churn in later patches quite a bit. Christoph also correctly points out that this makes codepaths (e.g. ioctls) way easier to follow that would otherwise have to do more complex argument passing than necessary. Link: https://lore.kernel.org/r/20210121131959.646623-4-christian.brauner@ubuntu.com Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Suggested-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-21 14:19:22 +01:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: reject FS_IOC_ENABLE_VERITY on mode 3 fds Commit 56124d6c87fd ("fsverity: support enabling with tree block size < PAGE_SIZE") changed FS_IOC_ENABLE_VERITY to use __kernel_read() to read the file's data, instead of direct pagecache accesses. An unintended consequence of this is that the 'WARN_ON_ONCE(!(file->f_mode & FMODE_READ))' in __kernel_read() became reachable by fuzz tests. This happens if FS_IOC_ENABLE_VERITY is called on a fd opened with access mode 3, which means "ioctl access only". Arguably, FS_IOC_ENABLE_VERITY should work on ioctl-only fds. But ioctl-only fds are a weird Linux extension that is rarely used and that few people even know about. (The documentation for FS_IOC_ENABLE_VERITY even specifically says it requires O_RDONLY.) It's probably not worthwhile to make the ioctl internally open a new fd just to handle this case. Thus, just reject the ioctl on such fds for now. Fixes: 56124d6c87fd ("fsverity: support enabling with tree block size < PAGE_SIZE") Reported-by: syzbot+51177e4144d764827c45@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=2281afcbbfa8fdb92f9887479cc0e4180f1c6b28 Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20230406215106.235829-1-ebiggers@kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-04-06 14:31:11 -07:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00
fsverity: don't drop pagecache at end of FS_IOC_ENABLE_VERITY The full pagecache drop at the end of FS_IOC_ENABLE_VERITY is causing performance problems and is hindering adoption of fsverity. It was intended to solve a race condition where unverified pages might be left in the pagecache. But actually it doesn't solve it fully. Since the incomplete solution for this race condition has too much performance impact for it to be worth it, let's remove it for now. Fixes: 3fda4c617e84 ("fs-verity: implement FS_IOC_ENABLE_VERITY ioctl") Cc: stable@vger.kernel.org Reviewed-by: Victor Hsieh <victorhsieh@google.com> Link: https://lore.kernel.org/r/20230314235332.50270-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2023-03-14 16:31:32 -07:00
fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 09:26:22 -07:00