[SRU][F][PATCH 0/1] CVE-2021-47212

[Koichiro Den]

[Impact]

net/mlx5: Update error handler for UCTX and UMEM

In the fast unload flow, the device state is set to internal error,
which indicates that the driver started the destroy process.
In this case, when a destroy command is being executed, it should return
MLX5_CMD_STAT_OK.
Fix MLX5_CMD_OP_DESTROY_UCTX and MLX5_CMD_OP_DESTROY_UMEM to return OK
instead of EIO.

This fixes a call trace in the umem release process -
[ 2633.536695] Call Trace:
[ 2633.537518]  ib_uverbs_remove_one+0xc3/0x140 [ib_uverbs]
[ 2633.538596]  remove_client_context+0x8b/0xd0 [ib_core]
[ 2633.539641]  disable_device+0x8c/0x130 [ib_core]
[ 2633.540615]  __ib_unregister_device+0x35/0xa0 [ib_core]
[ 2633.541640]  ib_unregister_device+0x21/0x30 [ib_core]
[ 2633.542663]  __mlx5_ib_remove+0x38/0x90 [mlx5_ib]
[ 2633.543640]  auxiliary_bus_remove+0x1e/0x30 [auxiliary]
[ 2633.544661]  device_release_driver_internal+0x103/0x1f0
[ 2633.545679]  bus_remove_device+0xf7/0x170
[ 2633.546640]  device_del+0x181/0x410
[ 2633.547606]  mlx5_rescan_drivers_locked.part.10+0x63/0x160 [mlx5_core]
[ 2633.548777]  mlx5_unregister_device+0x27/0x40 [mlx5_core]
[ 2633.549841]  mlx5_uninit_one+0x21/0xc0 [mlx5_core]
[ 2633.550864]  remove_one+0x69/0xe0 [mlx5_core]
[ 2633.551819]  pci_device_remove+0x3b/0xc0
[ 2633.552731]  device_release_driver_internal+0x103/0x1f0
[ 2633.553746]  unbind_store+0xf6/0x130
[ 2633.554657]  kernfs_fop_write+0x116/0x190
[ 2633.555567]  vfs_write+0xa5/0x1a0
[ 2633.556407]  ksys_write+0x4f/0xb0
[ 2633.557233]  do_syscall_64+0x5b/0x1a0
[ 2633.558071]  entry_SYSCALL_64_after_hwframe+0x65/0xca
[ 2633.559018] RIP: 0033:0x7f9977132648
[ 2633.559821] Code: 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 55 6f 2d 00 8b 00 85 c0 75 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 49 89 d4 55
[ 2633.562332] RSP: 002b:00007fffb1a83888 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 2633.563472] RAX: ffffffffffffffda RBX: 000000000000000c RCX: 00007f9977132648
[ 2633.564541] RDX: 000000000000000c RSI: 000055b90546e230 RDI: 0000000000000001
[ 2633.565596] RBP: 000055b90546e230 R08: 00007f9977406860 R09: 00007f9977a54740
[ 2633.566653] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f99774056e0
[ 2633.567692] R13: 000000000000000c R14: 00007f9977400880 R15: 000000000000000c
[ 2633.568725] ---[ end trace 10b4fe52945e544d ]---

[Backport]

Adjusted context due to missing commit 8f0105418668
("net/mlx5: SF, Add port add delete functionality").

[Fix]

Noble:  not affected
Jammy:  fixed via stable
Focal:  Backport - adjusted contexts due to missing commits, see [Backport]
Bionic: not affected
Xenial: not affected
Trusty: not affected

[Test case]

Compile and boot tested.

[Where problem could occur]

This fix affects those who use mlx5_ib driver and created UMEM and UCTX
in some form, an issue with this fix could potentially be visible to the
user via memory leak, which may not be an issue for fast unload case.
Note for Ubuntu Focal, the incorrect return value for
MLX5_CMD_OP_DESTROY_UMEM could not even lead to needless WARN message
with the backtrace shown in the original fix commit message.
Additionally, it's unclear that how this could be exploited for security
attacks. Still, the bug fix itself is not worthless.


Neta Ostrovsky (1):
  net/mlx5: Update error handler for UCTX and UMEM

 drivers/net/ethernet/mellanox/mlx5/core/cmd.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

-- 
2.43.0