bpf: Rename MEM_ALLOC to MEM_RINGBUF

Currently, verifier uses MEM_ALLOC type tag to specially tag memory
returned from bpf_ringbuf_reserve helper. However, this is currently
only used for this purpose and there is an implicit assumption that it
only refers to ringbuf memory (e.g. the check for ARG_PTR_TO_ALLOC_MEM
in check_func_arg_reg_off).

Hence, rename MEM_ALLOC to MEM_RINGBUF to indicate this special
relationship and instead open the use of MEM_ALLOC for more generic
allocations made for user types.

Also, since ARG_PTR_TO_ALLOC_MEM_OR_NULL is unused, simply drop it.

Finally, update selftests using 'alloc_' verifier string to 'ringbuf_'.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221114191547.1694267-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

2 files changed, 10 insertions, 10 deletions

diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c
index 9e832acf4692..80f4b4d88aaf 100644
--- a/kernel/bpf/ringbuf.c
+++ b/kernel/bpf/ringbuf.c
@@ -447,7 +447,7 @@ BPF_CALL_3(bpf_ringbuf_reserve, struct bpf_map *, map, u64, size, u64, flags)
 
 const struct bpf_func_proto bpf_ringbuf_reserve_proto = {
 	.func		= bpf_ringbuf_reserve,
-	.ret_type	= RET_PTR_TO_ALLOC_MEM_OR_NULL,
+	.ret_type	= RET_PTR_TO_RINGBUF_MEM_OR_NULL,
 	.arg1_type	= ARG_CONST_MAP_PTR,
 	.arg2_type	= ARG_CONST_ALLOC_SIZE_OR_ZERO,
 	.arg3_type	= ARG_ANYTHING,
@@ -490,7 +490,7 @@ BPF_CALL_2(bpf_ringbuf_submit, void *, sample, u64, flags)
 const struct bpf_func_proto bpf_ringbuf_submit_proto = {
 	.func		= bpf_ringbuf_submit,
 	.ret_type	= RET_VOID,
-	.arg1_type	= ARG_PTR_TO_ALLOC_MEM | OBJ_RELEASE,
+	.arg1_type	= ARG_PTR_TO_RINGBUF_MEM | OBJ_RELEASE,
 	.arg2_type	= ARG_ANYTHING,
 };
 
@@ -503,7 +503,7 @@ BPF_CALL_2(bpf_ringbuf_discard, void *, sample, u64, flags)
 const struct bpf_func_proto bpf_ringbuf_discard_proto = {
 	.func		= bpf_ringbuf_discard,
 	.ret_type	= RET_VOID,
-	.arg1_type	= ARG_PTR_TO_ALLOC_MEM | OBJ_RELEASE,
+	.arg1_type	= ARG_PTR_TO_RINGBUF_MEM | OBJ_RELEASE,
 	.arg2_type	= ARG_ANYTHING,
 };
 
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index c88da7e3ca74..c588e5483540 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -577,8 +577,8 @@ static const char *reg_type_str(struct bpf_verifier_env *env,
 
 	if (type & MEM_RDONLY)
 		strncpy(prefix, "rdonly_", 32);
-	if (type & MEM_ALLOC)
-		strncpy(prefix, "alloc_", 32);
+	if (type & MEM_RINGBUF)
+		strncpy(prefix, "ringbuf_", 32);
 	if (type & MEM_USER)
 		strncpy(prefix, "user_", 32);
 	if (type & MEM_PERCPU)
@@ -5785,7 +5785,7 @@ static const struct bpf_reg_types mem_types = {
 		PTR_TO_MAP_KEY,
 		PTR_TO_MAP_VALUE,
 		PTR_TO_MEM,
-		PTR_TO_MEM | MEM_ALLOC,
+		PTR_TO_MEM | MEM_RINGBUF,
 		PTR_TO_BUF,
 	},
 };
@@ -5803,7 +5803,7 @@ static const struct bpf_reg_types int_ptr_types = {
 static const struct bpf_reg_types fullsock_types = { .types = { PTR_TO_SOCKET } };
 static const struct bpf_reg_types scalar_types = { .types = { SCALAR_VALUE } };
 static const struct bpf_reg_types context_types = { .types = { PTR_TO_CTX } };
-static const struct bpf_reg_types alloc_mem_types = { .types = { PTR_TO_MEM | MEM_ALLOC } };
+static const struct bpf_reg_types ringbuf_mem_types = { .types = { PTR_TO_MEM | MEM_RINGBUF } };
 static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_TO_MAP } };
 static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID } };
 static const struct bpf_reg_types spin_lock_types = { .types = { PTR_TO_MAP_VALUE } };
@@ -5836,7 +5836,7 @@ static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = {
 	[ARG_PTR_TO_BTF_ID]		= &btf_ptr_types,
 	[ARG_PTR_TO_SPIN_LOCK]		= &spin_lock_types,
 	[ARG_PTR_TO_MEM]		= &mem_types,
-	[ARG_PTR_TO_ALLOC_MEM]		= &alloc_mem_types,
+	[ARG_PTR_TO_RINGBUF_MEM]	= &ringbuf_mem_types,
 	[ARG_PTR_TO_INT]		= &int_ptr_types,
 	[ARG_PTR_TO_LONG]		= &int_ptr_types,
 	[ARG_PTR_TO_PERCPU_BTF_ID]	= &percpu_btf_ptr_types,
@@ -5957,14 +5957,14 @@ int check_func_arg_reg_off(struct bpf_verifier_env *env,
 	case PTR_TO_MAP_VALUE:
 	case PTR_TO_MEM:
 	case PTR_TO_MEM | MEM_RDONLY:
-	case PTR_TO_MEM | MEM_ALLOC:
+	case PTR_TO_MEM | MEM_RINGBUF:
 	case PTR_TO_BUF:
 	case PTR_TO_BUF | MEM_RDONLY:
 	case SCALAR_VALUE:
 		/* Some of the argument types nevertheless require a
 		 * zero register offset.
 		 */
-		if (base_type(arg_type) != ARG_PTR_TO_ALLOC_MEM)
+		if (base_type(arg_type) != ARG_PTR_TO_RINGBUF_MEM)
 			return 0;
 		break;
 	/* All the rest must be rejected, except PTR_TO_BTF_ID which allows