The current code to override credentials for creation operations is
pretty difficult to understand. We effectively override the credentials
twice:
(1) override with the mounter's credentials
(2) copy the mounts credentials and override the fs{g,u}id with the inode {u,g}id
And then we elide the revert because it would be an idempotent revert.
That elision doesn't buy us anything anymore though because I've made it
all work without any reference counting anyway. All it does is mix the
two credential overrides together.
We can use a cleanup guard to clarify the creation codepaths and make
them easier to understand.
This just introduces the cleanup guard keeping the patch reviewable.
We'll convert the caller in follow-up patches and then drop the
duplicated code.
Link: https://patch.msgid.link/20251117-work-ovl-cred-guard-prepare-v2-1-bd1c97a36d7b@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Christian Brauner <brauner@kernel.org> says:
This adds an overlayfs specific extension of the cred guard
infrastructure I introduced. This allows all of overlayfs to be ported
to cred guards. I refactored a few functions to reduce the scope of the
cred guard. I think this is beneficial as it's visually very easy to
grasp the scope in one go. Lightly tested.
* patches from https://patch.msgid.link/20251117-work-ovl-cred-guard-v4-0-b31603935724@kernel.org: (42 commits)
ovl: remove ovl_revert_creds()
ovl: port ovl_fill_super() to cred guard
ovl: refactor ovl_fill_super()
ovl: port ovl_lower_positive() to cred guard
ovl: port ovl_lookup() to cred guard
ovl: refactor ovl_lookup()
ovl: port ovl_copyfile() to cred guard
ovl: port ovl_rename() to cred guard
ovl: refactor ovl_rename()
ovl: introduce struct ovl_renamedata
ovl: port ovl_listxattr() to cred guard
ovl: port ovl_xattr_get() to cred guard
ovl: port ovl_xattr_set() to cred guard
ovl: port ovl_nlink_end() to cred guard
ovl: port ovl_nlink_start() to cred guard
ovl: port ovl_check_empty_dir() to cred guard
ovl: port ovl_dir_llseek() to cred guard
ovl: refactor ovl_iterate() and port to cred guard
ovl: don't override credentials for ovl_check_whiteouts()
ovl: port ovl_maybe_lookup_lowerdata() to cred guard
...
Link: https://patch.msgid.link/20251117-work-ovl-cred-guard-v4-0-b31603935724@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Extract the code that runs under overridden credentials into a separate
ovl_rename_upper() helper function and the code that runs before/after to
ovl_rename_start/end(). Error handling is simplified.
The helpers returns errors directly instead of using goto labels.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://patch.msgid.link/20251117-work-ovl-cred-guard-v4-34-b31603935724@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Add a struct ovl_renamedata to group rename-related state that was
previously stored in local variables. Embedd struct renamedata directly
aligning with the vfs.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://patch.msgid.link/20251117-work-ovl-cred-guard-v4-33-b31603935724@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Overlayfs plucks the relevant creds from the superblock. Extend the
override_creds cleanup class I added to override_creds_ovl which uses
the ovl_override_creds() function as initialization helper. Add
with_ovl_creds() based on this new class.
Link: https://patch.msgid.link/20251117-work-ovl-cred-guard-v4-1-b31603935724@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Bring in the directory locking changes as they touch overlayfs in a
pretty substantial way and we are about to change the credential
override semantics quite substantially as well.
Signed-off-by: Christian Brauner <brauner@kernel.org>
Bring in the shared branch with the kbuild tree to enable
'-fms-extensions' for 6.19. The overlayfs cred guard work
depends on this.
Signed-off-by: Christian Brauner <brauner@kernel.org>
vgic_lpi_stress sends MAPTI and MAPC commands during guest GIC setup to
map interrupt events to ITT entries and collection IDs to
redistributors, respectively.
We have no guarantee that the ITS will finish handling these mapping
commands before the selftest calls KVM_SIGNAL_MSI to inject LPIs to the
guest. If LPIs are injected before ITS mapping completes, the ITS cannot
properly pass the interrupt on to the redistributor.
Fix by adding a SYNC command to the selftests ITS library, then calling
SYNC after ITS mapping to ensure mapping completes before signal_lpi()
writes to GITS_TRANSLATER.
Signed-off-by: Maximilian Dittgen <mdittgen@amazon.de>
Link: https://msgid.link/20251119135744.68552-2-mdittgen@amazon.de
Signed-off-by: Oliver Upton <oupton@kernel.org>
The selftests GIC library and tests assume that the
GICR_TYPER.Processor_number associated with a given CPU is the same as
the CPU's selftest index.
Since this assumption is not guaranteed by specification, add an assert
in gicv3_cpu_init() that validates this is true.
Signed-off-by: Maximilian Dittgen <mdittgen@amazon.de>
Link: https://msgid.link/20251119135744.68552-1-mdittgen@amazon.de
Signed-off-by: Oliver Upton <oupton@kernel.org>
