197bd9738a
[ Upstream commit 27b0420fd959e38e3500e60b637d39dfab065645 ] Recent commit that modified fib route event handler to handle events according to their priority introduced use-after-free[0] in mp->mfi pointer usage. The pointer now is not just cached in order to be compared to following fib_info instances, but is also dereferenced to obtain fib_priority. However, since mlx5 lag code doesn't hold the reference to fin_info during whole mp->mfi lifetime, it could be used after fib_info instance has already been freed be kernel infrastructure code. Don't ever dereference mp->mfi pointer. Refactor it to be 'const void*' type and cache fib_info priority in dedicated integer. Group fib_info-related data into dedicated 'fib' structure that will be further extended by following patches in the series. [0]: [ 203.588029] ================================================================== [ 203.590161] BUG: KASAN: use-after-free in mlx5_lag_fib_update+0xabd/0xd60 [mlx5_core] [ 203.592386] Read of size 4 at addr ffff888144df2050 by task kworker/u20:4/138 [ 203.594766] CPU: 3 PID: 138 Comm: kworker/u20:4 Tainted: G B 5.17.0-rc7+ #6 [ 203.596751] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 203.598813] Workqueue: mlx5_lag_mp mlx5_lag_fib_update [mlx5_core] [ 203.600053] Call Trace: [ 203.600608] <TASK> [ 203.601110] dump_stack_lvl+0x48/0x5e [ 203.601860] print_address_description.constprop.0+0x1f/0x160 [ 203.602950] ? mlx5_lag_fib_update+0xabd/0xd60 [mlx5_core] [ 203.604073] ? mlx5_lag_fib_update+0xabd/0xd60 [mlx5_core] [ 203.605177] kasan_report.cold+0x83/0xdf [ 203.605969] ? mlx5_lag_fib_update+0xabd/0xd60 [mlx5_core] [ 203.607102] mlx5_lag_fib_update+0xabd/0xd60 [mlx5_core] [ 203.608199] ? mlx5_lag_init_fib_work+0x1c0/0x1c0 [mlx5_core] [ 203.609382] ? read_word_at_a_time+0xe/0x20 [ 203.610463] ? strscpy+0xa0/0x2a0 [ 203.611463] process_one_work+0x722/0x1270 [ 203.612344] worker_thread+0x540/0x11e0 [ 203.613136] ? rescuer_thread+0xd50/0xd50 [ 203.613949] kthread+0x26e/0x300 [ 203.614627] ? kthread_complete_and_exit+0x20/0x20 [ 203.615542] ret_from_fork+0x1f/0x30 [ 203.616273] </TASK> [ 203.617174] Allocated by task 3746: [ 203.617874] kasan_save_stack+0x1e/0x40 [ 203.618644] __kasan_kmalloc+0x81/0xa0 [ 203.619394] fib_create_info+0xb41/0x3c50 [ 203.620213] fib_table_insert+0x190/0x1ff0 [ 203.621020] fib_magic.isra.0+0x246/0x2e0 [ 203.621803] fib_add_ifaddr+0x19f/0x670 [ 203.622563] fib_inetaddr_event+0x13f/0x270 [ 203.623377] blocking_notifier_call_chain+0xd4/0x130 [ 203.624355] __inet_insert_ifa+0x641/0xb20 [ 203.625185] inet_rtm_newaddr+0xc3d/0x16a0 [ 203.626009] rtnetlink_rcv_msg+0x309/0x880 [ 203.626826] netlink_rcv_skb+0x11d/0x340 [ 203.627626] netlink_unicast+0x4cc/0x790 [ 203.628430] netlink_sendmsg+0x762/0xc00 [ 203.629230] sock_sendmsg+0xb2/0xe0 [ 203.629955] ____sys_sendmsg+0x58a/0x770 [ 203.630756] ___sys_sendmsg+0xd8/0x160 [ 203.631523] __sys_sendmsg+0xb7/0x140 [ 203.632294] do_syscall_64+0x35/0x80 [ 203.633045] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 203.634427] Freed by task 0: [ 203.635063] kasan_save_stack+0x1e/0x40 [ 203.635844] kasan_set_track+0x21/0x30 [ 203.636618] kasan_set_free_info+0x20/0x30 [ 203.637450] __kasan_slab_free+0xfc/0x140 [ 203.638271] kfree+0x94/0x3b0 [ 203.638903] rcu_core+0x5e4/0x1990 [ 203.639640] __do_softirq+0x1ba/0x5d3 [ 203.640828] Last potentially related work creation: [ 203.641785] kasan_save_stack+0x1e/0x40 [ 203.642571] __kasan_record_aux_stack+0x9f/0xb0 [ 203.643478] call_rcu+0x88/0x9c0 [ 203.644178] fib_release_info+0x539/0x750 [ 203.644997] fib_table_delete+0x659/0xb80 [ 203.645809] fib_magic.isra.0+0x1a3/0x2e0 [ 203.646617] fib_del_ifaddr+0x93f/0x1300 [ 203.647415] fib_inetaddr_event+0x9f/0x270 [ 203.648251] blocking_notifier_call_chain+0xd4/0x130 [ 203.649225] __inet_del_ifa+0x474/0xc10 [ 203.650016] devinet_ioctl+0x781/0x17f0 [ 203.650788] inet_ioctl+0x1ad/0x290 [ 203.651533] sock_do_ioctl+0xce/0x1c0 [ 203.652315] sock_ioctl+0x27b/0x4f0 [ 203.653058] __x64_sys_ioctl+0x124/0x190 [ 203.653850] do_syscall_64+0x35/0x80 [ 203.654608] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 203.666952] The buggy address belongs to the object at ffff888144df2000 which belongs to the cache kmalloc-256 of size 256 [ 203.669250] The buggy address is located 80 bytes inside of 256-byte region [ffff888144df2000, ffff888144df2100) [ 203.671332] The buggy address belongs to the page: [ 203.672273] page:00000000bf6c9314 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x144df0 [ 203.674009] head:00000000bf6c9314 order:2 compound_mapcount:0 compound_pincount:0 [ 203.675422] flags: 0x2ffff800010200(slab|head|node=0|zone=2|lastcpupid=0x1ffff) [ 203.676819] raw: 002ffff800010200 0000000000000000 dead000000000122 ffff888100042b40 [ 203.678384] raw: 0000000000000000 0000000080200020 00000001ffffffff 0000000000000000 [ 203.679928] page dumped because: kasan: bad access detected [ 203.681455] Memory state around the buggy address: [ 203.682421] ffff888144df1f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 203.683863] ffff888144df1f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 203.685310] >ffff888144df2000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 203.686701] ^ [ 203.687820] ffff888144df2080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 203.689226] ffff888144df2100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 203.690620] ================================================================== Fixes: ad11c4f1d8fd ("net/mlx5e: Lag, Only handle events from highest priority multipath entry") Signed-off-by: Vlad Buslov <vladbu@nvidia.com> Reviewed-by: Maor Dickman <maord@nvidia.com> Reviewed-by: Leon Romanovsky <leonro@nvidia.com> Signed-off-by: Saeed Mahameed <saeedm@nvidia.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.