CVE-2024-50047: smb: client: fix UAF in async decryption
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 gf128mul4klle+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 smb2decryptoffload [cifs] [ 194.200032] Call Trace: [ 194.200191] <TASK> [ 194.200327] dumpstacklvl+0x4e/0x70 [ 194.200558] ? gf128mul4klle+0xc1/0x110 [ 194.200809] printreport+0x174/0x505 [ 194.201040] ? pfxrawspinlockirqsave+0x10/0x10 [ 194.201352] ? srsoreturnthunk+0x5/0x5f [ 194.201604] ? virtaddrvalid+0xdf/0x1c0 [ 194.201868] ? gf128mul4klle+0xc1/0x110 [ 194.202128] kasanreport+0xc8/0x150 [ 194.202361] ? gf128mul4klle+0xc1/0x110 [ 194.202616] gf128mul4klle+0xc1/0x110 [ 194.202863] ghashupdate+0x184/0x210 [ 194.203103] shashahashupdate+0x184/0x2a0 [ 194.203377] ? pfxshashahashupdate+0x10/0x10 [ 194.203651] ? srsoreturnthunk+0x5/0x5f [ 194.203877] ? cryptogcminitcommon+0x1ba/0x340 [ 194.204142] gcmhashassocremaincontinue+0x10a/0x140 [ 194.204434] cryptmessage+0xec1/0x10a0 [cifs] [ 194.206489] ? pfxcryptmessage+0x10/0x10 [cifs] [ 194.208507] ? srsoreturnthunk+0x5/0x5f [ 194.209205] ? srsoreturnthunk+0x5/0x5f [ 194.209925] ? srsoreturnthunk+0x5/0x5f [ 194.210443] ? srsoreturnthunk+0x5/0x5f [ 194.211037] decryptrawdata+0x15f/0x250 [cifs] [ 194.212906] ? pfxdecryptrawdata+0x10/0x10 [cifs] [ 194.214670] ? srsoreturnthunk+0x5/0x5f [ 194.215193] smb2decryptoffload+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 smb3calcsignature()).
Also remove the calls to aeadrequestsetcallback() and cryptowaitreq() since it's always going to be a synchronous operation.
Other sources
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 gf128mul4klle+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 smb2decryptoffload [cifs] [ 194.200032] Call Trace: [ 194.200191] <TASK> [ 194.200327] dumpstacklvl+0x4e/0x70 [ 194.200558] ? gf128mul4klle+0xc1/0x110 [ 194.200809] printreport+0x174/0x505 [ 194.201040] ? pfxrawspinlockirqsave+0x10/0x10 [ 194.201352] ? srsoreturnthunk+0x5/0x5f [ 194.201604] ? virtaddrvalid+0xdf/0x1c0 [ 194.201868] ? gf128mul4klle+0xc1/0x110 [ 194.202128] kasanreport+0xc8/0x150 [ 194.202361] ? gf128mul4klle+0xc1/0x110 [ 194.202616] gf128mul4klle+0xc1/0x110 [ 194.202863] ghashupdate+0x184/0x210 [ 194.203103] shashahashupdate+0x184/0x2a0 [ 194.203377] ? pfxshashahashupdate+0x10/0x10 [ 194.203651] ? srsoreturnthunk+0x5/0x5f [ 194.203877] ? cryptogcminitcommon+0x1ba/0x340 [ 194.204142] gcmhashassocremaincontinue+0x10a/0x140 [ 194.204434] cryptmessage+0xec1/0x10a0 [cifs] [ 194.206489] ? pfxcryptmessage+0x10/0x10 [cifs] [ 194.208507] ? srsoreturnthunk+0x5/0x5f [ 194.209205] ? srsoreturnthunk+0x5/0x5f [ 194.209925] ? srsoreturnthunk+0x5/0x5f [ 194.210443] ? srsoreturnthunk+0x5/0x5f [ 194.211037] decryptrawdata+0x15f/0x250 [cifs] [ 194.212906] ? pfxdecryptrawdata+0x10/0x10 [cifs] [ 194.214670] ? srsoreturnthunk+0x5/0x5f [ 194.215193] smb2decryptoffload+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 smb3calcsignature()).
Also remove the calls to aeadrequestsetcallback() and cryptowaitreq() since it's always going to be a synchronous operation.
— NVD
This CVE was automatically created from a reference found in an email or other text. If you are reading this, then this CVE entry is probably erroneous, since this text should be replaced by the official CVE description automatically.
— Launchpad
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.129-1Fixed in 6.1.135-1Fixed in 6.12.25-1Fixed in 6.12.27-1 - Upgrade
Upgrade
debian/linux-6.1to a version that resolves this vulnerability.Fixed in 6.1.129-1~deb11u1
Event History
Frequently Asked Questions
What is the severity of CVE-2024-50047?
CVE-2024-50047 has been classified as a high-severity vulnerability due to the potential for denial of service caused by a slab-use-after-free issue.
How do I fix CVE-2024-50047?
To fix CVE-2024-50047, update the Linux kernel to a version that is greater than 6.6.57 or between 6.7 and 6.11.4 inclusive.
Which Linux kernel versions are vulnerable to CVE-2024-50047?
Kernel versions prior to 6.6.57 and those between 6.7 and 6.11.4 are vulnerable to CVE-2024-50047.
What are the potential impacts of CVE-2024-50047?
The potential impacts of CVE-2024-50047 include system crashes and service interruptions due to the denial-of-service capability.
Is CVE-2024-50047 related to the SMB client functionality?
Yes, CVE-2024-50047 involves an issue in the SMB client related to asynchronous decryption processes.