Commit 2de2669b authored by Kumar Kartikeya Dwivedi's avatar Kumar Kartikeya Dwivedi Committed by Alexei Starovoitov
Browse files

bpf: Rename RET_PTR_TO_ALLOC_MEM 



Currently, the verifier has two return types, RET_PTR_TO_ALLOC_MEM, and
RET_PTR_TO_ALLOC_MEM_OR_NULL, however the former is confusingly named to
imply that it carries MEM_ALLOC, while only the latter does. This causes
confusion during code review leading to conclusions like that the return
value of RET_PTR_TO_DYNPTR_MEM_OR_NULL (which is RET_PTR_TO_ALLOC_MEM |
PTR_MAYBE_NULL) may be consumable by bpf_ringbuf_{submit,commit}.

Rename it to make it clear MEM_ALLOC needs to be tacked on top of
RET_PTR_TO_MEM.

Signed-off-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221114191547.1694267-6-memxor@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent f0c5941f

include/linux/bpf.h

+3 −3
Original line number Diff line number Diff line
@@ -607,7 +607,7 @@ enum bpf_return_type { 
	RET_PTR_TO_SOCKET,		/* returns a pointer to a socket */

	RET_PTR_TO_TCP_SOCK,		/* returns a pointer to a tcp_sock */

	RET_PTR_TO_SOCK_COMMON,		/* returns a pointer to a sock_common */

	RET_PTR_TO_ALLOC_MEM,		/* returns a pointer to dynamically allocated memory */

	RET_PTR_TO_MEM,			/* returns a pointer to memory */

	RET_PTR_TO_MEM_OR_BTF_ID,	/* returns a pointer to a valid memory or a btf_id */

	RET_PTR_TO_BTF_ID,		/* returns a pointer to a btf_id */

	__BPF_RET_TYPE_MAX,
@@ -617,8 +617,8 @@ enum bpf_return_type { 
	RET_PTR_TO_SOCKET_OR_NULL	= PTR_MAYBE_NULL | RET_PTR_TO_SOCKET,

	RET_PTR_TO_TCP_SOCK_OR_NULL	= PTR_MAYBE_NULL | RET_PTR_TO_TCP_SOCK,

	RET_PTR_TO_SOCK_COMMON_OR_NULL	= PTR_MAYBE_NULL | RET_PTR_TO_SOCK_COMMON,

	RET_PTR_TO_ALLOC_MEM_OR_NULL	= PTR_MAYBE_NULL | MEM_ALLOC | RET_PTR_TO_ALLOC_MEM,

	RET_PTR_TO_DYNPTR_MEM_OR_NULL	= PTR_MAYBE_NULL | RET_PTR_TO_ALLOC_MEM,

	RET_PTR_TO_ALLOC_MEM_OR_NULL	= PTR_MAYBE_NULL | MEM_ALLOC | RET_PTR_TO_MEM,

	RET_PTR_TO_DYNPTR_MEM_OR_NULL	= PTR_MAYBE_NULL | RET_PTR_TO_MEM,

	RET_PTR_TO_BTF_ID_OR_NULL	= PTR_MAYBE_NULL | RET_PTR_TO_BTF_ID,



	/* This must be the last entry. Its purpose is to ensure the enum is

kernel/bpf/verifier.c

+1 −1
Original line number Diff line number Diff line
@@ -7630,7 +7630,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn 
		mark_reg_known_zero(env, regs, BPF_REG_0);

		regs[BPF_REG_0].type = PTR_TO_TCP_SOCK | ret_flag;

		break;

	case RET_PTR_TO_ALLOC_MEM:

	case RET_PTR_TO_MEM:

		mark_reg_known_zero(env, regs, BPF_REG_0);

		regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;

		regs[BPF_REG_0].mem_size = meta.mem_size;