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David Howells 0c00e422bf cifs: Fix encryption of cleared, but unset rq_iter data buffers
commit 37de5a80e9 upstream.

Each smb_rqst struct contains two things: an array of kvecs (rq_iov) that
contains the protocol data for an RPC op and an iterator (rq_iter) that
contains the data payload of an RPC op.  When an smb_rqst is allocated
rq_iter is it always cleared, but we don't set it up unless we're going to
use it.

The functions that determines the size of the ciphertext buffer that will
be needed to encrypt a request, cifs_get_num_sgs(), assumes that rq_iter is
always initialised - and employs user_backed_iter() to check that the
iterator isn't user-backed.  This used to incidentally work, because
->user_backed was set to false because the iterator has never been
initialised, but with commit f1b4cb650b9a0eeba206d8f069fcdc532bfbcd74[1]
which changes user_backed_iter() to determine this based on the iterator
type insted, a warning is now emitted:

        WARNING: CPU: 7 PID: 4584 at fs/smb/client/cifsglob.h:2165 smb2_get_aead_req+0x3fc/0x420 [cifs]
        ...
        RIP: 0010:smb2_get_aead_req+0x3fc/0x420 [cifs]
        ...
         crypt_message+0x33e/0x550 [cifs]
         smb3_init_transform_rq+0x27d/0x3f0 [cifs]
         smb_send_rqst+0xc7/0x160 [cifs]
         compound_send_recv+0x3ca/0x9f0 [cifs]
         cifs_send_recv+0x25/0x30 [cifs]
         SMB2_tcon+0x38a/0x820 [cifs]
         cifs_get_smb_ses+0x69c/0xee0 [cifs]
         cifs_mount_get_session+0x76/0x1d0 [cifs]
         dfs_mount_share+0x74/0x9d0 [cifs]
         cifs_mount+0x6e/0x2e0 [cifs]
         cifs_smb3_do_mount+0x143/0x300 [cifs]
         smb3_get_tree+0x15e/0x290 [cifs]
         vfs_get_tree+0x2d/0xe0
         do_new_mount+0x124/0x340
         __se_sys_mount+0x143/0x1a0

The problem is that rq_iter was never set, so the type is 0 (ie. ITER_UBUF)
which causes user_backed_iter() to return true.  The code doesn't
malfunction because it checks the size of the iterator - which is 0.

Fix cifs_get_num_sgs() to ignore rq_iter if its count is 0, thereby
bypassing the warnings.

It might be better to explicitly initialise rq_iter to a zero-length
ITER_BVEC, say, as it can always be reinitialised later.

Fixes: d08089f649 ("cifs: Change the I/O paths to use an iterator rather than a page list")
Reported-by: Damian Tometzki <damian@riscv-rocks.de>
Closes: https://lore.kernel.org/r/ZUfQo47uo0p2ZsYg@fedora.fritz.box/
Tested-by: Damian Tometzki <damian@riscv-rocks.de>
Cc: stable@vger.kernel.org
cc: Eric Biggers <ebiggers@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f1b4cb650b9a0eeba206d8f069fcdc532bfbcd74 [1]
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2023-11-28 17:20:09 +00:00
arch parisc: fix mmap_base calculation when stack grows upwards 2023-11-28 17:20:08 +00:00
block blk-mq: make sure active queue usage is held for bio_integrity_prep() 2023-11-28 17:19:51 +00:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: pcrypt - Fix hungtask for PADATA_RESET 2023-11-28 17:19:42 +00:00
Documentation dt-bindings: timer: renesas,rz-mtu3: Fix overflow/underflow interrupt names 2023-11-28 17:20:02 +00:00
drivers xhci: Enable RPM on controllers that support low-power states 2023-11-28 17:20:08 +00:00
fs cifs: Fix encryption of cleared, but unset rq_iter data buffers 2023-11-28 17:20:09 +00:00
include torture: Make torture_hrtimeout_ns() take an hrtimer mode parameter 2023-11-28 17:20:08 +00:00
init proc: sysctl: prevent aliased sysctls from getting passed to init 2023-11-28 17:19:57 +00:00
io_uring io_uring/fdinfo: remove need for sqpoll lock for thread/pid retrieval 2023-11-28 17:19:52 +00:00
ipc Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
kernel rcutorture: Fix stuttering races and other issues 2023-11-28 17:20:08 +00:00
lib lib/generic-radix-tree.c: Don't overflow in peek() 2023-11-28 17:19:35 +00:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm parisc: fix mmap_base calculation when stack grows upwards 2023-11-28 17:20:08 +00:00
net netfilter: nf_tables: split async and sync catchall in two functions 2023-11-28 17:20:03 +00:00
rust rust: docs: fix logo replacement 2023-10-19 16:40:00 +02:00
samples samples/bpf: syscall_tp_user: Fix array out-of-bound access 2023-11-28 17:19:48 +00:00
scripts scripts/gdb/vmalloc: disable on no-MMU 2023-11-28 17:20:05 +00:00
security apparmor: Fix regression in mount mediation 2023-11-28 17:20:07 +00:00
sound ASoC: codecs: wsa-macro: fix uninitialized stack variables with name prefix 2023-11-28 17:20:04 +00:00
tools selftests/resctrl: Extend signal handler coverage to unmount on receiving signal 2023-11-28 17:20:08 +00:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt ARM: 2023-09-07 13:52:20 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: rename binkernel.spec to kernel.spec 2023-07-25 00:59:33 +09:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Char/Misc driver fixes for 6.6-final 2023-10-28 07:51:27 -10:00
Makefile Linux 6.6.2 2023-11-20 11:59:39 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.