On 14.03.2023 16:04:45, Ivan Orlov wrote: > 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@xxxxxxxxxxxxxxxxxxxxxxxxx > Link: https://syzkaller.appspot.com/bug?id=47f897f8ad958bbde5790ebf389b5e7e0a345089 > Signed-off-by: Ivan Orlov <ivan.orlov0322@xxxxxxxxx> Applied to linux-can. Thanks, Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung Nürnberg | Phone: +49-5121-206917-129 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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