CVE-2024-40947
- Source
- https://nvd.nist.gov/vuln/detail/CVE-2024-40947
- Import Source
- https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2024-40947.json
- JSON Data
- https://api.test.osv.dev/v1/vulns/CVE-2024-40947
- Downstream
- Related
- Published
- 2024-07-12T12:31:52Z
- Modified
- 2025-10-09T14:07:57.825212Z
- Summary
- ima: Avoid blocking in RCU read-side critical section
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
ima: Avoid blocking in RCU read-side critical section
A panic happens in imamatchpolicy:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 PGD 42f873067 P4D 0 Oops: 0000 [#1] SMP NOPTI CPU: 5 PID: 1286325 Comm: kubeletmonit.sh Kdump: loaded Tainted: P Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 RIP: 0010:imamatchpolicy+0x84/0x450 Code: 49 89 fc 41 89 cf 31 ed 89 44 24 14 eb 1c 44 39 7b 18 74 26 41 83 ff 05 74 20 48 8b 1b 48 3b 1d f2 b9 f4 00 0f 84 9c 01 00 00 <44> 85 73 10 74 ea 44 8b 6b 14 41 f6 c5 01 75 d4 41 f6 c5 02 74 0f RSP: 0018:ff71570009e07a80 EFLAGS: 00010207 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000200 RDX: ffffffffad8dc7c0 RSI: 0000000024924925 RDI: ff3e27850dea2000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffffabfce739 R10: ff3e27810cc42400 R11: 0000000000000000 R12: ff3e2781825ef970 R13: 00000000ff3e2785 R14: 000000000000000c R15: 0000000000000001 FS: 00007f5195b51740(0000) GS:ff3e278b12d40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000010 CR3: 0000000626d24002 CR4: 0000000000361ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: imagetaction+0x22/0x30 processmeasurement+0xb0/0x830 ? pageaddfilermap+0x15/0x170 ? allocsetpte+0x269/0x4c0 ? prepnewpage+0x81/0x140 ? simplexattrget+0x75/0xa0 ? selinuxfileopen+0x9d/0xf0 imafilecheck+0x64/0x90 pathopenat+0x571/0x1720 dofilpopen+0x9b/0x110 ? pagecountertrycharge+0x57/0xc0 ? filescgroupallocfd+0x38/0x60 ? _allocfd+0xd4/0x250 ? dosysopen+0x1bd/0x250 dosysopen+0x1bd/0x250 dosyscall64+0x5d/0x1d0 entrySYSCALL64after_hwframe+0x65/0xca
Commit c7423dbdbc9e ("ima: Handle -ESTALE returned by imafilterrulematch()") introduced call to imalsmcopyrule within a RCU read-side critical section which contains kmalloc with GFP_KERNEL. This implies a possible sleep and violates limitations of RCU read-side critical sections on non-PREEMPT systems.
Sleeping within RCU read-side critical section might cause synchronize_rcu() returning early and break RCU protection, allowing a UAF to happen.
The root cause of this issue could be described as follows: | Thread A | Thread B | | |imamatchpolicy | | | rcureadlock | |imalsmupdaterule | | | synchronizercu | | | | kmalloc(GFPKERNEL)| | | sleep | ==> synchronizercu returns early | kfree(entry) | | | | entry = entry->next| ==> UAF happens and entry now becomes NULL (or could be anything). | | entry->action | ==> Accessing entry might cause panic.
To fix this issue, we are converting all kmalloc that is called within RCU read-side critical section to use GFP_ATOMIC.
[PM: fixed missing comment, long lines, !CONFIGIMALSM_RULES case]
- References
-
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- https://git.kernel.org/stable/c/28d0ecc52f6c927d0e9ba70a4f2c1ea15453ee88
- https://git.kernel.org/stable/c/58275455893066149e9f4df2223ab2fdbdc59f9c
- https://git.kernel.org/stable/c/9a95c5bfbf02a0a7f5983280fe284a0ff0836c34
- https://git.kernel.org/stable/c/9c3906c3738562b1fedc6f1cfc81756a7cfefff0
- https://git.kernel.org/stable/c/a38e02265c681b51997a264aaf743095e2ee400a
- https://git.kernel.org/stable/c/a6176a802c4bfb83bf7524591aa75f44a639a853
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedc4b035b1f036ddd53fbfced49046e586c5ad8a3eFixeda6176a802c4bfb83bf7524591aa75f44a639a853
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced2d4bc60693c4206c64723e94ae5f7a04c0b8f18fFixeda38e02265c681b51997a264aaf743095e2ee400a
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced8008f1691c15f353f5a53dc5d450b8262cb57421Fixed9c3906c3738562b1fedc6f1cfc81756a7cfefff0
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedc7423dbdbc9ecef7fff5239d144cad4b9887f4deFixed28d0ecc52f6c927d0e9ba70a4f2c1ea15453ee88
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedc7423dbdbc9ecef7fff5239d144cad4b9887f4deFixed58275455893066149e9f4df2223ab2fdbdc59f9c
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedc7423dbdbc9ecef7fff5239d144cad4b9887f4deFixed9a95c5bfbf02a0a7f5983280fe284a0ff0836c34
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced38d48fd224036717fcb3437e7af1314f6ebcd2d0
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced69c60b2a2dbb4887739d3a13297cc0dae3793f35
Affected versions
v5.*
v6.*
Linux / Kernel
Package
- Name
- Kernel
Affected ranges
- Type
- ECOSYSTEM
- Events
-
Introduced0Unknown introduced version / All previous versions are affectedFixed5.10.222
- Type
- ECOSYSTEM
- Events
-
Introduced5.11.0Fixed5.15.163
- Type
- ECOSYSTEM
- Events
-
Introduced5.16.0Fixed6.1.98
- Type
- ECOSYSTEM
- Events
-
Introduced6.2.0Fixed6.6.39
- Type
- ECOSYSTEM
- Events
-
Introduced6.2.0Fixed6.9.7