CVE-2024-50047

smb: client: fix UAF in async decryption

HIGH

7.8

CVSS Score

Published: October 21, 2024 at 07:39 PM UTC

Updated: August 5, 2026 at 12:05 PM UTC

1 product affected across 1 vendorLinux Kernel

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Severity

HIGH7.8

Exploit prediction

EPSS 0.5%

SSVC

No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix UAF in async decryption Doing an async decryption (large read) crashes with a slab-use-after-free way down in the crypto API. Reproducer: # mount.cifs -o ...,seal,esize=1 //srv/share /mnt # dd if=/mnt/largefile of=/dev/null ... [ 194.196391] ================================================================== [ 194.196844] BUG: KASAN: slab-use-after-free in gf128mul_4k_lle+0xc1/0x110 [ 194.197269] Read of size 8 at addr ffff888112bd0448 by task kworker/u77:2/899 [ 194.197707] [ 194.197818] CPU: 12 UID: 0 PID: 899 Comm: kworker/u77:2 Not tainted 6.11.0-lku-00028-gfca3ca14a17a-dirty #43 [ 194.198400] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.2-3-gd478f380-prebuilt.qemu.org 04/01/2014 [ 194.199046] Workqueue: smb3decryptd smb2_decrypt_offload [cifs] [ 194.200032] Call Trace: [ 194.200191] <TASK> [ 194.200327] dump_stack_lvl+0x4e/0x70 [ 194.200558] ? gf128mul_4k_lle+0xc1/0x110 [ 194.200809] print_report+0x174/0x505 [ 194.201040] ? __pfx__raw_spin_lock_irqsave+0x10/0x10 [ 194.201352] ? srso_return_thunk+0x5/0x5f [ 194.201604] ? __virt_addr_valid+0xdf/0x1c0 [ 194.201868] ? gf128mul_4k_lle+0xc1/0x110 [ 194.202128] kasan_report+0xc8/0x150 [ 194.202361] ? gf128mul_4k_lle+0xc1/0x110 [ 194.202616] gf128mul_4k_lle+0xc1/0x110 [ 194.202863] ghash_update+0x184/0x210 [ 194.203103] shash_ahash_update+0x184/0x2a0 [ 194.203377] ? __pfx_shash_ahash_update+0x10/0x10 [ 194.203651] ? srso_return_thunk+0x5/0x5f [ 194.203877] ? crypto_gcm_init_common+0x1ba/0x340 [ 194.204142] gcm_hash_assoc_remain_continue+0x10a/0x140 [ 194.204434] crypt_message+0xec1/0x10a0 [cifs] [ 194.206489] ? __pfx_crypt_message+0x10/0x10 [cifs] [ 194.208507] ? srso_return_thunk+0x5/0x5f [ 194.209205] ? srso_return_thunk+0x5/0x5f [ 194.209925] ? srso_return_thunk+0x5/0x5f [ 194.210443] ? srso_return_thunk+0x5/0x5f [ 194.211037] decrypt_raw_data+0x15f/0x250 [cifs] [ 194.212906] ? __pfx_decrypt_raw_data+0x10/0x10 [cifs] [ 194.214670] ? srso_return_thunk+0x5/0x5f [ 194.215193] smb2_decrypt_offload+0x12a/0x6c0 [cifs] This is because TFM is being used in parallel. Fix this by allocating a new AEAD TFM for async decryption, but keep the existing one for synchronous READ cases (similar to what is done in smb3_calc_signature()). Also remove the calls to aead_request_set_callback() and crypto_wait_req() since it's always going to be a synchronous operation.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Linux Kernel · Linux

95%

v < 6.6.575.4 ≤ v < 5.10.2375.4 ≤ v < 5.15.1815.4 ≤ v < 6.1.1285.4 ≤ v < 6.11.45.4 ≤ v < 6.125.4 ≤ v < 6.6.576.7 ≤ v < 6.11.435cf94a397280b9e27576ac1480f631bdd3e7b705.4

Vendor states this is fixed in 538c26d9bf70c90edc460d18c81008a4e555925a (fixed)

Vendor states this is fixed in 809fb86ad13b29e1d6d491364fc7ea4fb545995 (fixed)

Vendor states this is fixed in 8f14a476abba13144df5434871a7225fd29af633 (fixed)

Vendor states this is fixed in b0abcd65ec545701b8793e12bc27dc98042b151a (fixed)

Vendor states this is fixed in bce966530fd5542bbb422cb45ecb775f7a1a6bc3 (fixed)

Vendor states this is fixed in ef51c0d544b1518b35364480317ab6d3468f205d (fixed)

Vendor states this is fixed in 5.10.237 (unaffected)

Vendor states this is fixed in 5.15.181 (unaffected)

Vendor states this is fixed in 5.4 (unaffected)

Vendor states this is fixed in 6.1.128 (unaffected)

Vendor states this is fixed in 6.11.4 (unaffected)

Vendor states this is fixed in 6.12 (unaffected)