bpf: Zero index arg error string for dynptr and iter

Andrii spotted that process_dynptr_func's rejection of incorrect
argument register type will print an error string where argument numbers
are not zero-indexed, unlike elsewhere in the verifier.  Fix this by
subtracting 1 from regno. The same scenario exists for iterator
messages. Fix selftest error strings that match on the exact argument
number while we're at it to ensure clean bisection.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20241203002235.3776418-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 358a3566bb60a5cada24d8db593fed4c69811a06..2fd35465d650a0338a58ffe87d8d8ea085910c38 100644 (file)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -8071,7 +8071,7 @@ static int process_dynptr_func(struct bpf_verifier_env *env, int regno, int insn
        if (reg->type != PTR_TO_STACK && reg->type != CONST_PTR_TO_DYNPTR) {
                verbose(env,
                        "arg#%d expected pointer to stack or const struct bpf_dynptr\n",
-                       regno);
+                       regno - 1);
                return -EINVAL;
        }
 
@@ -8125,7 +8125,7 @@ static int process_dynptr_func(struct bpf_verifier_env *env, int regno, int insn
                if (!is_dynptr_reg_valid_init(env, reg)) {
                        verbose(env,
                                "Expected an initialized dynptr as arg #%d\n",
-                               regno);
+                               regno - 1);
                        return -EINVAL;
                }
 
@@ -8133,7 +8133,7 @@ static int process_dynptr_func(struct bpf_verifier_env *env, int regno, int insn
                if (!is_dynptr_type_expected(env, reg, arg_type & ~MEM_RDONLY)) {
                        verbose(env,
                                "Expected a dynptr of type %s as arg #%d\n",
-                               dynptr_type_str(arg_to_dynptr_type(arg_type)), regno);
+                               dynptr_type_str(arg_to_dynptr_type(arg_type)), regno - 1);
                        return -EINVAL;
                }
 
@@ -8202,7 +8202,7 @@ static int process_iter_arg(struct bpf_verifier_env *env, int regno, int insn_id
         */
        btf_id = btf_check_iter_arg(meta->btf, meta->func_proto, regno - 1);
        if (btf_id < 0) {
-               verbose(env, "expected valid iter pointer as arg #%d\n", regno);
+               verbose(env, "expected valid iter pointer as arg #%d\n", regno - 1);
                return -EINVAL;
        }
        t = btf_type_by_id(meta->btf, btf_id);
@@ -8212,7 +8212,7 @@ static int process_iter_arg(struct bpf_verifier_env *env, int regno, int insn_id
                /* bpf_iter_<type>_new() expects pointer to uninit iter state */
                if (!is_iter_reg_valid_uninit(env, reg, nr_slots)) {
                        verbose(env, "expected uninitialized iter_%s as arg #%d\n",
-                               iter_type_str(meta->btf, btf_id), regno);
+                               iter_type_str(meta->btf, btf_id), regno - 1);
                        return -EINVAL;
                }
 
@@ -8236,7 +8236,7 @@ static int process_iter_arg(struct bpf_verifier_env *env, int regno, int insn_id
                        break;
                case -EINVAL:
                        verbose(env, "expected an initialized iter_%s as arg #%d\n",
-                               iter_type_str(meta->btf, btf_id), regno);
+                               iter_type_str(meta->btf, btf_id), regno - 1);
                        return err;
                case -EPROTO:
                        verbose(env, "expected an RCU CS when using %s\n", meta->func_name);

diff --git a/tools/testing/selftests/bpf/progs/dynptr_fail.c b/tools/testing/selftests/bpf/progs/dynptr_fail.c
index 8f36c9de759152117d07457aca72f0ab30ea16be..dfd817d0348c473dc47cdb63dada22e609cc8eca 100644 (file)
--- a/tools/testing/selftests/bpf/progs/dynptr_fail.c
+++ b/tools/testing/selftests/bpf/progs/dynptr_fail.c
@@ -149,7 +149,7 @@ int ringbuf_release_uninit_dynptr(void *ctx)
 
 /* A dynptr can't be used after it has been invalidated */
 SEC("?raw_tp")
-__failure __msg("Expected an initialized dynptr as arg #3")
+__failure __msg("Expected an initialized dynptr as arg #2")
 int use_after_invalid(void *ctx)
 {
        struct bpf_dynptr ptr;
@@ -428,7 +428,7 @@ int invalid_helper2(void *ctx)
 
 /* A bpf_dynptr is invalidated if it's been written into */
 SEC("?raw_tp")
-__failure __msg("Expected an initialized dynptr as arg #1")
+__failure __msg("Expected an initialized dynptr as arg #0")
 int invalid_write1(void *ctx)
 {
        struct bpf_dynptr ptr;
@@ -1407,7 +1407,7 @@ int invalid_slice_rdwr_rdonly(struct __sk_buff *skb)
 
 /* bpf_dynptr_adjust can only be called on initialized dynptrs */
 SEC("?raw_tp")
-__failure __msg("Expected an initialized dynptr as arg #1")
+__failure __msg("Expected an initialized dynptr as arg #0")
 int dynptr_adjust_invalid(void *ctx)
 {
        struct bpf_dynptr ptr = {};
@@ -1420,7 +1420,7 @@ int dynptr_adjust_invalid(void *ctx)
 
 /* bpf_dynptr_is_null can only be called on initialized dynptrs */
 SEC("?raw_tp")
-__failure __msg("Expected an initialized dynptr as arg #1")
+__failure __msg("Expected an initialized dynptr as arg #0")
 int dynptr_is_null_invalid(void *ctx)
 {
        struct bpf_dynptr ptr = {};
@@ -1433,7 +1433,7 @@ int dynptr_is_null_invalid(void *ctx)
 
 /* bpf_dynptr_is_rdonly can only be called on initialized dynptrs */
 SEC("?raw_tp")
-__failure __msg("Expected an initialized dynptr as arg #1")
+__failure __msg("Expected an initialized dynptr as arg #0")
 int dynptr_is_rdonly_invalid(void *ctx)
 {
        struct bpf_dynptr ptr = {};
@@ -1446,7 +1446,7 @@ int dynptr_is_rdonly_invalid(void *ctx)
 
 /* bpf_dynptr_size can only be called on initialized dynptrs */
 SEC("?raw_tp")
-__failure __msg("Expected an initialized dynptr as arg #1")
+__failure __msg("Expected an initialized dynptr as arg #0")
 int dynptr_size_invalid(void *ctx)
 {
        struct bpf_dynptr ptr = {};
@@ -1459,7 +1459,7 @@ int dynptr_size_invalid(void *ctx)
 
 /* Only initialized dynptrs can be cloned */
 SEC("?raw_tp")
-__failure __msg("Expected an initialized dynptr as arg #1")
+__failure __msg("Expected an initialized dynptr as arg #0")
 int clone_invalid1(void *ctx)
 {
        struct bpf_dynptr ptr1 = {};
@@ -1493,7 +1493,7 @@ int clone_invalid2(struct xdp_md *xdp)
 
 /* Invalidating a dynptr should invalidate its clones */
 SEC("?raw_tp")
-__failure __msg("Expected an initialized dynptr as arg #3")
+__failure __msg("Expected an initialized dynptr as arg #2")
 int clone_invalidate1(void *ctx)
 {
        struct bpf_dynptr clone;
@@ -1514,7 +1514,7 @@ int clone_invalidate1(void *ctx)
 
 /* Invalidating a dynptr should invalidate its parent */
 SEC("?raw_tp")
-__failure __msg("Expected an initialized dynptr as arg #3")
+__failure __msg("Expected an initialized dynptr as arg #2")
 int clone_invalidate2(void *ctx)
 {
        struct bpf_dynptr ptr;
@@ -1535,7 +1535,7 @@ int clone_invalidate2(void *ctx)
 
 /* Invalidating a dynptr should invalidate its siblings */
 SEC("?raw_tp")
-__failure __msg("Expected an initialized dynptr as arg #3")
+__failure __msg("Expected an initialized dynptr as arg #2")
 int clone_invalidate3(void *ctx)
 {
        struct bpf_dynptr ptr;
@@ -1723,7 +1723,7 @@ __noinline long global_call_bpf_dynptr(const struct bpf_dynptr *dynptr)
 }
 
 SEC("?raw_tp")
-__failure __msg("arg#1 expected pointer to stack or const struct bpf_dynptr")
+__failure __msg("arg#0 expected pointer to stack or const struct bpf_dynptr")
 int test_dynptr_reg_type(void *ctx)
 {
        struct task_struct *current = NULL;

diff --git a/tools/testing/selftests/bpf/progs/iters_state_safety.c b/tools/testing/selftests/bpf/progs/iters_state_safety.c
index d47e59aba6de3512d1e5f217f28741083e767f1f..f41257eadbb258cd4c26fa03b1834353536f7e04 100644 (file)
--- a/tools/testing/selftests/bpf/progs/iters_state_safety.c
+++ b/tools/testing/selftests/bpf/progs/iters_state_safety.c
@@ -73,7 +73,7 @@ int create_and_forget_to_destroy_fail(void *ctx)
 }
 
 SEC("?raw_tp")
-__failure __msg("expected an initialized iter_num as arg #1")
+__failure __msg("expected an initialized iter_num as arg #0")
 int destroy_without_creating_fail(void *ctx)
 {
        /* init with zeros to stop verifier complaining about uninit stack */
@@ -91,7 +91,7 @@ int destroy_without_creating_fail(void *ctx)
 }
 
 SEC("?raw_tp")
-__failure __msg("expected an initialized iter_num as arg #1")
+__failure __msg("expected an initialized iter_num as arg #0")
 int compromise_iter_w_direct_write_fail(void *ctx)
 {
        struct bpf_iter_num iter;
@@ -143,7 +143,7 @@ int compromise_iter_w_direct_write_and_skip_destroy_fail(void *ctx)
 }
 
 SEC("?raw_tp")
-__failure __msg("expected an initialized iter_num as arg #1")
+__failure __msg("expected an initialized iter_num as arg #0")
 int compromise_iter_w_helper_write_fail(void *ctx)
 {
        struct bpf_iter_num iter;
@@ -230,7 +230,7 @@ int valid_stack_reuse(void *ctx)
 }
 
 SEC("?raw_tp")
-__failure __msg("expected uninitialized iter_num as arg #1")
+__failure __msg("expected uninitialized iter_num as arg #0")
 int double_create_fail(void *ctx)
 {
        struct bpf_iter_num iter;
@@ -258,7 +258,7 @@ int double_create_fail(void *ctx)
 }
 
 SEC("?raw_tp")
-__failure __msg("expected an initialized iter_num as arg #1")
+__failure __msg("expected an initialized iter_num as arg #0")
 int double_destroy_fail(void *ctx)
 {
        struct bpf_iter_num iter;
@@ -284,7 +284,7 @@ int double_destroy_fail(void *ctx)
 }
 
 SEC("?raw_tp")
-__failure __msg("expected an initialized iter_num as arg #1")
+__failure __msg("expected an initialized iter_num as arg #0")
 int next_without_new_fail(void *ctx)
 {
        struct bpf_iter_num iter;
@@ -305,7 +305,7 @@ int next_without_new_fail(void *ctx)
 }
 
 SEC("?raw_tp")
-__failure __msg("expected an initialized iter_num as arg #1")
+__failure __msg("expected an initialized iter_num as arg #0")
 int next_after_destroy_fail(void *ctx)
 {
        struct bpf_iter_num iter;

diff --git a/tools/testing/selftests/bpf/progs/iters_testmod_seq.c b/tools/testing/selftests/bpf/progs/iters_testmod_seq.c
index 4a176e6aede897a760ca8246e4ec63f7efcb6ffe..6543d5b6e0a976b7af2d723177698f15517643d7 100644 (file)
--- a/tools/testing/selftests/bpf/progs/iters_testmod_seq.c
+++ b/tools/testing/selftests/bpf/progs/iters_testmod_seq.c
@@ -79,7 +79,7 @@ int testmod_seq_truncated(const void *ctx)
 
 SEC("?raw_tp")
 __failure
-__msg("expected an initialized iter_testmod_seq as arg #2")
+__msg("expected an initialized iter_testmod_seq as arg #1")
 int testmod_seq_getter_before_bad(const void *ctx)
 {
        struct bpf_iter_testmod_seq it;
@@ -89,7 +89,7 @@ int testmod_seq_getter_before_bad(const void *ctx)
 
 SEC("?raw_tp")
 __failure
-__msg("expected an initialized iter_testmod_seq as arg #2")
+__msg("expected an initialized iter_testmod_seq as arg #1")
 int testmod_seq_getter_after_bad(const void *ctx)
 {
        struct bpf_iter_testmod_seq it;

diff --git a/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c b/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
index e68667aec6a652b208b2b29a9ae5a8e3c0193c40..cd4d752bd089ca58bb4c135b9486a61ed5e5c4c9 100644 (file)
--- a/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
+++ b/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c
@@ -45,7 +45,7 @@ int BPF_PROG(not_valid_dynptr, int cmd, union bpf_attr *attr, unsigned int size)
 }
 
 SEC("?lsm.s/bpf")
-__failure __msg("arg#1 expected pointer to stack or const struct bpf_dynptr")
+__failure __msg("arg#0 expected pointer to stack or const struct bpf_dynptr")
 int BPF_PROG(not_ptr_to_stack, int cmd, union bpf_attr *attr, unsigned int size)
 {
        unsigned long val = 0;

diff --git a/tools/testing/selftests/bpf/progs/verifier_bits_iter.c b/tools/testing/selftests/bpf/progs/verifier_bits_iter.c
index a7a6ae6c162fe0a8e585397449cd70afda598fbd..8bcddadfc4daed3c34f474dea952499fe8256393 100644 (file)
--- a/tools/testing/selftests/bpf/progs/verifier_bits_iter.c
+++ b/tools/testing/selftests/bpf/progs/verifier_bits_iter.c
@@ -32,7 +32,7 @@ int BPF_PROG(no_destroy, struct bpf_iter_meta *meta, struct cgroup *cgrp)
 
 SEC("iter/cgroup")
 __description("uninitialized iter in ->next()")
-__failure __msg("expected an initialized iter_bits as arg #1")
+__failure __msg("expected an initialized iter_bits as arg #0")
 int BPF_PROG(next_uninit, struct bpf_iter_meta *meta, struct cgroup *cgrp)
 {
        struct bpf_iter_bits it = {};
@@ -43,7 +43,7 @@ int BPF_PROG(next_uninit, struct bpf_iter_meta *meta, struct cgroup *cgrp)
 
 SEC("iter/cgroup")
 __description("uninitialized iter in ->destroy()")
-__failure __msg("expected an initialized iter_bits as arg #1")
+__failure __msg("expected an initialized iter_bits as arg #0")
 int BPF_PROG(destroy_uninit, struct bpf_iter_meta *meta, struct cgroup *cgrp)
 {
        struct bpf_iter_bits it = {};