ima: Avoid blocking in RCU read-side critical section

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2024-40947
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2024-07-12 13:15:17 UTC
Updated2026-08-04 11:19:08 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: ima: Avoid blocking in RCU read-side critical section A panic happens in ima_match_policy: 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:ima_match_policy+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: ima_get_action+0x22/0x30 process_measurement+0xb0/0x830 ? page_add_file_rmap+0x15/0x170 ? alloc_set_pte+0x269/0x4c0 ? prep_new_page+0x81/0x140 ? simple_xattr_get+0x75/0xa0 ? selinux_file_open+0x9d/0xf0 ima_file_check+0x64/0x90 path_openat+0x571/0x1720 do_filp_open+0x9b/0x110 ? page_counter_try_charge+0x57/0xc0 ? files_cgroup_alloc_fd+0x38/0x60 ? __alloc_fd+0xd4/0x250 ? do_sys_open+0x1bd/0x250 do_sys_open+0x1bd/0x250 do_syscall_64+0x5d/0x1d0 entry_SYSCALL_64_after_hwframe+0x65/0xca Commit c7423dbdbc9e ("ima: Handle -ESTALE returned by ima_filter_rule_match()") introduced call to ima_lsm_copy_rule 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 | | |ima_match_policy | | | rcu_read_lock | |ima_lsm_update_rule | | | synchronize_rcu | | | | kmalloc(GFP_KERNEL)| | | sleep | ==> synchronize_rcu 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, !CONFIG_IMA_LSM_RULES case]

Risk And Classification

Primary CVSS: v3.1 5.5 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-476

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary5.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected c4b035b1f036ddd53fbfced49046e586c5ad8a3e a6176a802c4bfb83bf7524591aa75f44a639a853 git Not specified
CNA Linux Linux affected 2d4bc60693c4206c64723e94ae5f7a04c0b8f18f a38e02265c681b51997a264aaf743095e2ee400a git Not specified
CNA Linux Linux affected 8008f1691c15f353f5a53dc5d450b8262cb57421 9c3906c3738562b1fedc6f1cfc81756a7cfefff0 git Not specified
CNA Linux Linux affected c7423dbdbc9ecef7fff5239d144cad4b9887f4de 28d0ecc52f6c927d0e9ba70a4f2c1ea15453ee88 git Not specified
CNA Linux Linux affected c7423dbdbc9ecef7fff5239d144cad4b9887f4de 58275455893066149e9f4df2223ab2fdbdc59f9c git Not specified
CNA Linux Linux affected c7423dbdbc9ecef7fff5239d144cad4b9887f4de 9a95c5bfbf02a0a7f5983280fe284a0ff0836c34 git Not specified
CNA Linux Linux affected 38d48fd224036717fcb3437e7af1314f6ebcd2d0 git Not specified
CNA Linux Linux affected 69c60b2a2dbb4887739d3a13297cc0dae3793f35 git Not specified
CNA Linux Linux affected 5.10.163 5.10.222 semver Not specified
CNA Linux Linux affected 5.15.86 5.15.163 semver Not specified
CNA Linux Linux affected 6.1.2 6.1.98 semver Not specified
CNA Linux Linux affected 5.4.229 5.5 semver Not specified
CNA Linux Linux affected 6.0.16 6.1 semver Not specified
CNA Linux Linux affected 6.2 Not specified
CNA Linux Linux unaffected 6.2 semver Not specified
CNA Linux Linux unaffected 5.10.222 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.163 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.98 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.39 6.6.* semver Not specified
CNA Linux Linux unaffected 6.9.7 6.9.* semver Not specified
CNA Linux Linux unaffected 6.10 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/58275455893066149e9f4df2223ab2fdbdc59f9c af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/9c3906c3738562b1fedc6f1cfc81756a7cfefff0 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/28d0ecc52f6c927d0e9ba70a4f2c1ea15453ee88 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/a38e02265c681b51997a264aaf743095e2ee400a af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
lists.debian.org/debian-lts-announce/2025/01/msg00001.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org
git.kernel.org/stable/c/9a95c5bfbf02a0a7f5983280fe284a0ff0836c34 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
git.kernel.org/stable/c/a6176a802c4bfb83bf7524591aa75f44a639a853 af854a3a-2127-422b-91ae-364da2661108 git.kernel.org Patch
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