From: Jann Horn Date: Mon, 18 Dec 2017 20:11:57 -0800 Subject: [5/9] bpf: fix missing error return in check_stack_boundary() Origin: https://git.kernel.org/linus/ea25f914dc164c8d56b36147ecc86bc65f83c469 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 --- kernel/bpf/verifier.c | 1 + 1 file changed, 1 insertion(+) --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1320,6 +1320,7 @@ static int check_stack_boundary(struct b 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 ||