From b051d0a5bca367dbafe5edf8e3aab9c9c9ce59ae Mon Sep 17 00:00:00 2001 From: Jann Horn Date: Mon, 18 Dec 2017 20:11:57 -0800 Subject: [PATCH] bpf: fix missing error return in check_stack_boundary() Prevent indirect stack accesses at non-constant addresses, which would permit reading and corrupting spilled pointers. Fixes: f1174f77b50c ("bpf/verifier: rework value tracking") Signed-off-by: Jann Horn Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Gbp-Pq: Topic bugfix/all Gbp-Pq: Name bpf-fix-missing-error-return-in-check_stack_boundary.patch --- kernel/bpf/verifier.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index e6d15c0cf3b..a9f9a5e57ba 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1320,6 +1320,7 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno, tnum_strn(tn_buf, sizeof(tn_buf), regs[regno].var_off); verbose(env, "invalid variable stack read R%d var_off=%s\n", regno, tn_buf); + return -EACCES; } off = regs[regno].off + regs[regno].var_off.value; if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 || -- 2.30.2