bpf: don't check spilled reg state for non-STACK_SPILLed type slots

spilled_regs[] state is only used for stack slots of type STACK_SPILL, never for STACK_MISC. Right now, in states_equal(), even if we have old and current stack state of type STACK_MISC, we compare spilled_regs[] for that particular offset. Just skip these like we do everywhere else. Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: Alexei Starovoitov <[email protected]> Signed-off-by: David S. Miller <[email protected]>
ambv · Jun 10, 2017 · d25da6c · d25da6c
1 parent 20b9d7a
commit d25da6c
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
@@ -2828,6 +2828,8 @@ static bool states_equal(struct bpf_verifier_env *env,
 			return false;
 		if (i % BPF_REG_SIZE)
 			continue;
+		if (old->stack_slot_type[i] != STACK_SPILL)
+			continue;
 		if (memcmp(&old->spilled_regs[i / BPF_REG_SIZE],
 			   &cur->spilled_regs[i / BPF_REG_SIZE],
 			   sizeof(old->spilled_regs[0])))