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bpf: mark relevant stack slots scratched for register read instructions

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When handling instructions that read register slots, mark relevant stack
slots as scratched so that verifier log would contain those slots' states, in
addition to currently emitted registers with stack slot offsets.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230505043317.3629845-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Andrii Nakryiko
2023-05-04 21:33:09 -07:00
committed by Alexei Starovoitov
parent 5956f30116
commit e0bf462276
1 changed files with 3 additions and 0 deletions
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3
kernel/bpf/verifier.c
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@@ -4109,6 +4109,7 @@ static void mark_reg_stack_read(struct bpf_verifier_env *env,
for (i = min_off; i < max_off; i++) {
slot = -i - 1;
spi = slot / BPF_REG_SIZE;
mark_stack_slot_scratched(env, spi);
stype = ptr_state->stack[spi].slot_type;
if (stype[slot % BPF_REG_SIZE] != STACK_ZERO)
break;
@@ -4160,6 +4161,8 @@ static int check_stack_read_fixed_off(struct bpf_verifier_env *env,
stype = reg_state->stack[spi].slot_type;
reg = &reg_state->stack[spi].spilled_ptr;
mark_stack_slot_scratched(env, spi);
if (is_spilled_reg(&reg_state->stack[spi])) {
u8 spill_size = 1;