Bug 2348196 (CVE-2022-49094)

Summary: CVE-2022-49094 kernel: net/tls: fix slab-out-of-bounds bug in decrypt_internal
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was discovered in the Linux kernel’s TLS subsystem (net/tls) related to AES128‑CCM decryption in the decrypt_internal() function. The issue stems from a mismatch between the initialization vector (IV) buffer size (tls_ctx->rx.iv) set to 12 bytes in tls_set_sw_offload() and the 16-byte IV size returned by crypto_aead_ivsize("ccm(aes)"). As a result, a memcpy() operation copies 16 bytes into a 12-byte buffer, causing a slab out-of-bounds access. A local attacker with low privileges could exploit this flaw to trigger memory corruption, leading to system instability or denial of service.
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Description OSIDB Bzimport 2025-02-26 03:20:58 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net/tls: fix slab-out-of-bounds bug in decrypt_internal

The memory size of tls_ctx->rx.iv for AES128-CCM is 12 setting in
tls_set_sw_offload(). The return value of crypto_aead_ivsize()
for "ccm(aes)" is 16. So memcpy() require 16 bytes from 12 bytes
memory space will trigger slab-out-of-bounds bug as following:

==================================================================
BUG: KASAN: slab-out-of-bounds in decrypt_internal+0x385/0xc40 [tls]
Read of size 16 at addr ffff888114e84e60 by task tls/10911

Call Trace:
 <TASK>
 dump_stack_lvl+0x34/0x44
 print_report.cold+0x5e/0x5db
 ? decrypt_internal+0x385/0xc40 [tls]
 kasan_report+0xab/0x120
 ? decrypt_internal+0x385/0xc40 [tls]
 kasan_check_range+0xf9/0x1e0
 memcpy+0x20/0x60
 decrypt_internal+0x385/0xc40 [tls]
 ? tls_get_rec+0x2e0/0x2e0 [tls]
 ? process_rx_list+0x1a5/0x420 [tls]
 ? tls_setup_from_iter.constprop.0+0x2e0/0x2e0 [tls]
 decrypt_skb_update+0x9d/0x400 [tls]
 tls_sw_recvmsg+0x3c8/0xb50 [tls]

Allocated by task 10911:
 kasan_save_stack+0x1e/0x40
 __kasan_kmalloc+0x81/0xa0
 tls_set_sw_offload+0x2eb/0xa20 [tls]
 tls_setsockopt+0x68c/0x700 [tls]
 __sys_setsockopt+0xfe/0x1b0

Replace the crypto_aead_ivsize() with prot->iv_size + prot->salt_size
when memcpy() iv value in TLS_1_3_VERSION scenario.
Comment 1 Avinash Hanwate 2025-02-26 19:16:22 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022659-CVE-2022-49094-9749@gregkh/T