CVE-2024-35917
Description
In the Linux kernel, the following vulnerability has been resolved: s390/bpf: Fix bpf_plt pointer arithmetic Kui-Feng Lee reported a crash on s390x triggered by the dummy_st_ops/dummy_init_ptr_arg test [1]: [<0000000000000002>] 0x2 [<00000000009d5cde>] bpf_struct_ops_test_run+0x156/0x250 [<000000000033145a>] __sys_bpf+0xa1a/0xd00 [<00000000003319dc>] __s390x_sys_bpf+0x44/0x50 [<0000000000c4382c>] __do_syscall+0x244/0x300 [<0000000000c59a40>] system_call+0x70/0x98 This is caused by GCC moving memcpy() after assignments in bpf_jit_plt(), resulting in NULL pointers being written instead of the return and the target addresses. Looking at the GCC internals, the reordering is allowed because the alias analysis thinks that the memcpy() destination and the assignments' left-hand-sides are based on different objects: new_plt and bpf_plt_ret/bpf_plt_target respectively, and therefore they cannot alias. This is in turn due to a violation of the C standard: When two pointers are subtracted, both shall point to elements of the same array object, or one past the last element of the array object ... From the C's perspective, bpf_plt_ret and bpf_plt are distinct objects and cannot be subtracted. In the practical terms, doing so confuses the GCC's alias analysis. The code was written this way in order to let the C side know a few offsets defined in the assembly. While nice, this is by no means necessary. Fix the noncompliance by hardcoding these offsets. [1] https://lore.kernel.org/bpf/c9923c1d-971d-4022-8dc8-1364e929d34c@gmail.com/
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Mitigation details
CVE-2024-35917 NameCVE-2024-35917 DescriptionIn the Linux kernel, the following vulnerability has been resolved: s390/bpf: Fix bpf_plt pointer arithmetic Kui-Feng Lee reported a crash on s390x triggered by the dummy_st_ops/dummy_init_ptr_arg test [1]: [<0000000000000002>] 0x2 [<00000000009d5cde>] bpf_struct_ops_test_run+0x156/0x250 [<000000000033145a>] __sys_bpf+0xa1a/0xd00 [<00000000003319dc>]…
CVE-2024-35917
| Name | CVE-2024-35917 |
| Description | In the Linux kernel, the following vulnerability has been resolved: s390/bpf: Fix bpf_plt pointer arithmetic Kui-Feng Lee reported a crash on s390x triggered by the dummy_st_ops/dummy_init_ptr_arg test [1]: [<0000000000000002>] 0x2 [<00000000009d5cde>] bpf_struct_ops_test_run+0x156/0x250 [<000000000033145a>] __sys_bpf+0xa1a/0xd00 [<00000000003319dc>] __s390x_sys_bpf+0x44/0x50 [<0000000000c4382c>] __do_syscall+0x244/0x300 [<0000000000c59a40>] system_call+0x70/0x98 This is caused by GCC moving memcpy() after assignments in bpf_jit_plt(), resulting in NULL pointers being written instead of the return and the target addresses. Looking at the GCC internals, the reordering is allowed because the alias analysis thinks that the memcpy() destination and the assignments' left-hand-sides are based on different objects: new_plt and bpf_plt_ret/bpf_plt_target respectively, and therefore they cannot alias. This is in turn due to a violation of the C standard: When two pointers are subtracted, both shall point to elements of the same array object, or one past the last element of the array object ... From the C's perspective, bpf_plt_ret and bpf_plt are distinct objects and cannot be subtracted. In the practical terms, doing so confuses the GCC's alias analysis. The code was written this way in order to let the C side know a few offsets defined in the assembly. While nice, this is by no means necessary. Fix the noncompliance by hardcoding these offsets. [1] https://lore.kernel.org/bpf/c9923c1d-971d-4022-8dc8-1364e929d34c@gmail.com/ |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| linux (PTS) | bullseye | 5.10.223-1 | fixed |
| bullseye (security) | 5.10.257-1 | fixed | |
| bookworm | 6.1.170-3 | fixed | |
| bookworm (security) | 6.1.174-1 | fixed | |
| trixie | 6.12.86-1 | fixed | |
| trixie (security) | 6.12.90-2 | fixed | |
| forky, sid | 7.0.10-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| linux | source | buster | (not affected) | |||
| linux | source | bullseye | (not affected) | |||
| linux | source | bookworm | (not affected) | |||
| linux | source | (unstable) | 6.8.9-1 |
Notes
[bookworm] - linux <not-affected> (Vulnerable code not present)
[bullseye] - linux <not-affected> (Vulnerable code not present)
[buster] - linux <not-affected> (Vulnerable code not present)
https://git.kernel.org/linus/7ded842b356d151ece8ac4985940438e6d3998bb (6.9-rc2)
Apply commands
[bookworm] - linux <not-affected> (Vulnerable code not present)[bullseye] - linux <not-affected> (Vulnerable code not present)[buster] - linux <not-affected> (Vulnerable code not present)https://git.kernel.org/linus/7ded842b356d151ece8ac4985940438e6d3998bb (6.9-rc2)OS impact
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Fixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 6.8.9-1 |
| sid | Fixed | 6.8.9-1 |
| forky | Fixed | 6.8.9-1 |
| bullseye | Fixed | 0 |
| bookworm | Fixed | 0 |
References
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.