CVE-2026-23417
Gravedad:
Pendiente de análisis
Tipo:
No Disponible / Otro tipo
Fecha de publicación:
02/04/2026
Última modificación:
02/04/2026
Descripción
*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br />
<br />
bpf: Fix constant blinding for PROBE_MEM32 stores<br />
<br />
BPF_ST | BPF_PROBE_MEM32 immediate stores are not handled by<br />
bpf_jit_blind_insn(), allowing user-controlled 32-bit immediates to<br />
survive unblinded into JIT-compiled native code when bpf_jit_harden >= 1.<br />
<br />
The root cause is that convert_ctx_accesses() rewrites BPF_ST|BPF_MEM<br />
to BPF_ST|BPF_PROBE_MEM32 for arena pointer stores during verification,<br />
before bpf_jit_blind_constants() runs during JIT compilation. The<br />
blinding switch only matches BPF_ST|BPF_MEM (mode 0x60), not<br />
BPF_ST|BPF_PROBE_MEM32 (mode 0xa0). The instruction falls through<br />
unblinded.<br />
<br />
Add BPF_ST|BPF_PROBE_MEM32 cases to bpf_jit_blind_insn() alongside the<br />
existing BPF_ST|BPF_MEM cases. The blinding transformation is identical:<br />
load the blinded immediate into BPF_REG_AX via mov+xor, then convert<br />
the immediate store to a register store (BPF_STX).<br />
<br />
The rewritten STX instruction must preserve the BPF_PROBE_MEM32 mode so<br />
the architecture JIT emits the correct arena addressing (R12-based on<br />
x86-64). Cannot use the BPF_STX_MEM() macro here because it hardcodes<br />
BPF_MEM mode; construct the instruction directly instead.



