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| author | Ivan Orlov <ivan.orlov0322@gmail.com> | 2023-03-14 16:04:45 +0400 |
|---|---|---|
| committer | Marc Kleine-Budde <mkl@pengutronix.de> | 2023-03-27 14:40:45 +0200 |
| commit | 2b4c99f7d9a57ecd644eda9b1fb0a1072414959f (patch) | |
| tree | 0aad1350c1d926f34d085ca52998702d60366e7a /net/can | |
| parent | d1366b283d94ac4537a4b3a1e8668da4df7ce7e9 (diff) | |
can: bcm: bcm_tx_setup(): fix KMSAN uninit-value in vfs_write
Syzkaller reported the following issue:
=====================================================
BUG: KMSAN: uninit-value in aio_rw_done fs/aio.c:1520 [inline]
BUG: KMSAN: uninit-value in aio_write+0x899/0x950 fs/aio.c:1600
aio_rw_done fs/aio.c:1520 [inline]
aio_write+0x899/0x950 fs/aio.c:1600
io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
__do_sys_io_submit fs/aio.c:2078 [inline]
__se_sys_io_submit+0x293/0x770 fs/aio.c:2048
__x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Uninit was created at:
slab_post_alloc_hook mm/slab.h:766 [inline]
slab_alloc_node mm/slub.c:3452 [inline]
__kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491
__do_kmalloc_node mm/slab_common.c:967 [inline]
__kmalloc+0x11d/0x3b0 mm/slab_common.c:981
kmalloc_array include/linux/slab.h:636 [inline]
bcm_tx_setup+0x80e/0x29d0 net/can/bcm.c:930
bcm_sendmsg+0x3a2/0xce0 net/can/bcm.c:1351
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg net/socket.c:734 [inline]
sock_write_iter+0x495/0x5e0 net/socket.c:1108
call_write_iter include/linux/fs.h:2189 [inline]
aio_write+0x63a/0x950 fs/aio.c:1600
io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
__do_sys_io_submit fs/aio.c:2078 [inline]
__se_sys_io_submit+0x293/0x770 fs/aio.c:2048
__x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
CPU: 1 PID: 5034 Comm: syz-executor350 Not tainted 6.2.0-rc6-syzkaller-80422-geda666ff2276 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
=====================================================
We can follow the call chain and find that 'bcm_tx_setup' function
calls 'memcpy_from_msg' to copy some content to the newly allocated
frame of 'op->frames'. After that the 'len' field of copied structure
being compared with some constant value (64 or 8). However, if
'memcpy_from_msg' returns an error, we will compare some uninitialized
memory. This triggers 'uninit-value' issue.
This patch will add 'memcpy_from_msg' possible errors processing to
avoid uninit-value issue.
Tested via syzkaller
Reported-by: syzbot+c9bfd85eca611ebf5db1@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=47f897f8ad958bbde5790ebf389b5e7e0a345089
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Fixes: 6f3b911d5f29b ("can: bcm: add support for CAN FD frames")
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/all/20230314120445.12407-1-ivan.orlov0322@gmail.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Diffstat (limited to 'net/can')
| -rw-r--r-- | net/can/bcm.c | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/net/can/bcm.c b/net/can/bcm.c index 27706f6ace34..a962ec2b8ba5 100644 --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -941,6 +941,8 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, cf = op->frames + op->cfsiz * i; err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz); + if (err < 0) + goto free_op; if (op->flags & CAN_FD_FRAME) { if (cf->len > 64) @@ -950,12 +952,8 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, err = -EINVAL; } - if (err < 0) { - if (op->frames != &op->sframe) - kfree(op->frames); - kfree(op); - return err; - } + if (err < 0) + goto free_op; if (msg_head->flags & TX_CP_CAN_ID) { /* copy can_id into frame */ @@ -1026,6 +1024,12 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, bcm_tx_start_timer(op); return msg_head->nframes * op->cfsiz + MHSIZ; + +free_op: + if (op->frames != &op->sframe) + kfree(op->frames); + kfree(op); + return err; } /* |