diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index b35fc80238846..7f1b3a862e141 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1689,7 +1689,16 @@ st: if (is_imm8(insn->off)) } if (image) { - if (unlikely(proglen + ilen > oldproglen)) { + /* + * When populating the image, assert that: + * + * i) We do not write beyond the allocated space, and + * ii) addrs[i] did not change from the prior run, in order + * to validate assumptions made for computing branch + * displacements. + */ + if (unlikely(proglen + ilen > oldproglen || + proglen + ilen != addrs[i])) { pr_err("bpf_jit: fatal error\n"); return -EFAULT; }