diff options
| -rw-r--r-- | kernel/bpf/verifier.c | 5 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/test_verifier.c | 34 |
2 files changed, 37 insertions, 2 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 0125731e2512..e0e77ffeefb8 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1286,6 +1286,10 @@ static int check_stack_write(struct bpf_verifier_env *env, /* regular write of data into stack destroys any spilled ptr */ state->stack[spi].spilled_ptr.type = NOT_INIT; + /* Mark slots as STACK_MISC if they belonged to spilled ptr. */ + if (state->stack[spi].slot_type[0] == STACK_SPILL) + for (i = 0; i < BPF_REG_SIZE; i++) + state->stack[spi].slot_type[i] = STACK_MISC; /* only mark the slot as written if all 8 bytes were written * otherwise read propagation may incorrectly stop too soon @@ -1303,6 +1307,7 @@ static int check_stack_write(struct bpf_verifier_env *env, register_is_null(&cur->regs[value_regno])) type = STACK_ZERO; + /* Mark slots affected by this stack write. */ for (i = 0; i < size; i++) state->stack[spi].slot_type[(slot - i) % BPF_REG_SIZE] = type; diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index f9de7fe0c26d..cf242734e2eb 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -1001,15 +1001,45 @@ static struct bpf_test tests[] = { BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_1, -8), /* mess up with R1 pointer on stack */ BPF_ST_MEM(BPF_B, BPF_REG_10, -7, 0x23), - /* fill back into R0 should fail */ + /* fill back into R0 is fine for priv. + * R0 now becomes SCALAR_VALUE. + */ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8), + /* Load from R0 should fail. */ + BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 8), BPF_EXIT_INSN(), }, .errstr_unpriv = "attempt to corrupt spilled", - .errstr = "corrupted spill", + .errstr = "R0 invalid mem access 'inv", .result = REJECT, }, { + "check corrupted spill/fill, LSB", + .insns = { + BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_1, -8), + BPF_ST_MEM(BPF_H, BPF_REG_10, -8, 0xcafe), + BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8), + BPF_EXIT_INSN(), + }, + .errstr_unpriv = "attempt to corrupt spilled", + .result_unpriv = REJECT, + .result = ACCEPT, + .retval = POINTER_VALUE, + }, + { + "check corrupted spill/fill, MSB", + .insns = { + BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_1, -8), + BPF_ST_MEM(BPF_W, BPF_REG_10, -4, 0x12345678), + BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8), + BPF_EXIT_INSN(), + }, + .errstr_unpriv = "attempt to corrupt spilled", + .result_unpriv = REJECT, + .result = ACCEPT, + .retval = POINTER_VALUE, + }, + { "invalid src register in STX", .insns = { BPF_STX_MEM(BPF_B, BPF_REG_10, -1, -1), |