CVE-2025-38279
- Source
- https://nvd.nist.gov/vuln/detail/CVE-2025-38279
- Import Source
- https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-38279.json
- JSON Data
- https://api.test.osv.dev/v1/vulns/CVE-2025-38279
- Downstream
- Related
- Published
- 2025-07-10T07:41:58Z
- Modified
- 2025-10-10T13:12:17.025431Z
- Summary
- bpf: Do not include stack ptr register in precision backtracking bookkeeping
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
bpf: Do not include stack ptr register in precision backtracking bookkeeping
Yi Lai reported an issue ([1]) where the following warning appears in kernel dmesg: [ 60.643604] verifier backtracking bug [ 60.643635] WARNING: CPU: 10 PID: 2315 at kernel/bpf/verifier.c:4302 markchainprecision+0x3a6c/0x3e10 [ 60.648428] Modules linked in: bpftestmod(OE) [ 60.650471] CPU: 10 UID: 0 PID: 2315 Comm: testprogs Tainted: G OE 6.15.0-rc4-gef11287f8289-dirty #327 PREEMPT(full) [ 60.654385] Tainted: [O]=OOTMODULE, [E]=UNSIGNEDMODULE [ 60.656682] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 60.660475] RIP: 0010:markchainprecision+0x3a6c/0x3e10 [ 60.662814] Code: 5a 30 84 89 ea e8 c4 d9 01 00 80 3d 3e 7d d8 04 00 0f 85 60 fa ff ff c6 05 31 7d d8 04 01 48 c7 c7 00 58 30 84 e8 c4 06 a5 ff <0f> 0b e9 46 fa ff ff 48 ... [ 60.668720] RSP: 0018:ffff888116cc7298 EFLAGS: 00010246 [ 60.671075] RAX: 54d70e82dfd31900 RBX: ffff888115b65e20 RCX: 0000000000000000 [ 60.673659] RDX: 0000000000000001 RSI: 0000000000000004 RDI: 00000000ffffffff [ 60.676241] RBP: 0000000000000400 R08: ffff8881f6f23bd3 R09: 1ffff1103ede477a [ 60.678787] R10: dffffc0000000000 R11: ffffed103ede477b R12: ffff888115b60ae8 [ 60.681420] R13: 1ffff11022b6cbc4 R14: 00000000fffffff2 R15: 0000000000000001 [ 60.684030] FS: 00007fc2aedd80c0(0000) GS:ffff88826fa8a000(0000) knlGS:0000000000000000 [ 60.686837] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 60.689027] CR2: 000056325369e000 CR3: 000000011088b002 CR4: 0000000000370ef0 [ 60.691623] Call Trace: [ 60.692821] <TASK> [ 60.693960] ? _pfxverbose+0x10/0x10 [ 60.695656] ? _pfxdisasmkfuncname+0x10/0x10 [ 60.697495] checkcondjmpop+0x16f7/0x39b0 [ 60.699237] docheck+0x58fa/0xab10 ...
Further analysis shows the warning is at line 4302 as below:
4294 /* static subprog call instruction, which 4295 * means that we are exiting current subprog, 4296 * so only r1-r5 could be still requested as 4297 * precise, r0 and r6-r10 or any stack slot in 4298 * the current frame should be zero by now 4299 */ 4300 if (btregmask(bt) & ~BPFREGMASKARGS) { 4301 verbose(env, "BUG regs %x\n", btregmask(bt)); 4302 WARN_ONCE(1, "verifier backtracking bug"); 4303 return -EFAULT; 4304 }
With the below test (also in the next patch): _used _naked static void _bpfjmpr10(void) { asm volatile ( "r2 = 2314885393468386424 ll;" "goto +0;" "if r2 <= r10 goto +3;" "if r1 >= -1835016 goto +0;" "if r2 <= 8 goto +0;" "if r3 <= 0 goto +0;" "exit;" ::: _clobber_all); }
SEC("?rawtp") _naked void bpfjmpr10(void) { asm volatile ( "r3 = 0 ll;" "call _bpfjmpr10;" "r0 = 0;" "exit;" ::: _clobber_all); }
The following is the verifier failure log: 0: (18) r3 = 0x0 ; R3w=0 2: (85) call pc+2 caller: R10=fp0 callee: frame1: R1=ctx() R3w=0 R10=fp0 5: frame1: R1=ctx() R3w=0 R10=fp0 ; asm volatile (" \ @ verifierprecision.c:184 5: (18) r2 = 0x20202000256c6c78 ; frame1: R2w=0x20202000256c6c78 7: (05) goto pc+0 8: (bd) if r2 <= r10 goto pc+3 ; frame1: R2w=0x20202000256c6c78 R10=fp0 9: (35) if r1 >= 0xffe3fff8 goto pc+0 ; frame1: R1=ctx() 10: (b5) if r2 <= 0x8 goto pc+0 markprecise: frame1: lastidx 10 firstidx 0 subseqidx -1 markprecise: frame1: regs=r2 stack= before 9: (35) if r1 >= 0xffe3fff8 goto pc+0 markprecise: frame1: regs=r2 stack= before 8: (bd) if r2 <= r10 goto pc+3 mark_preci ---truncated---
- References
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
-
Introduced407958a0e980b9e1842ab87b5a1040521e1e24e9Fixed4265682c29c92f52c0da6fad5a79b5801462c8de
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced407958a0e980b9e1842ab87b5a1040521e1e24e9Fixedac49b7560b4b08b1e4043a29214cc7ad77644c00
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced407958a0e980b9e1842ab87b5a1040521e1e24e9Fixede2d2115e56c4a02377189bfc3a9a7933552a7b0f
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedfc2778c42f99c7de52fc004157b3c3ee4dcc208a