Commit 58ff3a14 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by Xiaomeng Zhang
Browse files

bpf: Add MEM_WRITE attribute 

stable inclusion
from stable-v6.6.59
commit 8a33a047bd31a7047b8dffe688c2c10e1ab871eb
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IB2SUA
CVE: CVE-2024-50164

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8a33a047bd31a7047b8dff



--------------------------------

[ Upstream commit 6fad274f06f038c29660aa53fbad14241c9fd976 ]

Add a MEM_WRITE attribute for BPF helper functions which can be used in
bpf_func_proto to annotate an argument type in order to let the verifier
know that the helper writes into the memory passed as an argument. In
the past MEM_UNINIT has been (ab)used for this function, but the latter
merely tells the verifier that the passed memory can be uninitialized.

There have been bugs with overloading the latter but aside from that
there are also cases where the passed memory is read + written which
currently cannot be expressed, see also 4b3786a6c539 ("bpf: Zero former
ARG_PTR_TO_{LONG,INT} args in case of error").

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20241021152809.33343-1-daniel@iogearbox.net


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Stable-dep-of: 8ea607330a39 ("bpf: Fix overloading of MEM_UNINIT's meaning")
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Conflicts:
	include/linux/bpf.h
[The conflicts were due to not merge the commit d8747fd2837aa]
Signed-off-by: default avatarXiaomeng Zhang <zhangxiaomeng13@huawei.com>
parent 70125123

include/linux/bpf.h

+11 −3
Original line number Diff line number Diff line
@@ -625,6 +625,7 @@ enum bpf_type_flag { 
	 */

	PTR_UNTRUSTED		= BIT(6 + BPF_BASE_TYPE_BITS),



	/* MEM can be uninitialized. */

	MEM_UNINIT		= BIT(7 + BPF_BASE_TYPE_BITS),



	/* DYNPTR points to memory local to the bpf program. */
@@ -691,6 +692,13 @@ enum bpf_type_flag { 
	/* Fix kabi by inserting broken enum as bpf_type_flag is used only in kernel */

	KABI_BROKEN_INSERT_ENUM(MEM_ALIGNED = BIT(17 + BPF_BASE_TYPE_BITS))



	/* MEM is being written to, often combined with MEM_UNINIT. Non-presence

	 * of MEM_WRITE means that MEM is only being read. MEM_WRITE without the

	 * MEM_UNINIT means that memory needs to be initialized since it is also

	 * read.

	 */

	MEM_WRITE		= BIT(18 + BPF_BASE_TYPE_BITS),



	__BPF_TYPE_FLAG_MAX,

	__BPF_TYPE_LAST_FLAG	= __BPF_TYPE_FLAG_MAX - 1,

};
@@ -751,10 +759,10 @@ enum bpf_arg_type { 
	ARG_PTR_TO_SOCKET_OR_NULL	= PTR_MAYBE_NULL | ARG_PTR_TO_SOCKET,

	ARG_PTR_TO_STACK_OR_NULL	= PTR_MAYBE_NULL | ARG_PTR_TO_STACK,

	ARG_PTR_TO_BTF_ID_OR_NULL	= PTR_MAYBE_NULL | ARG_PTR_TO_BTF_ID,

	/* pointer to memory does not need to be initialized, helper function must fill

	 * all bytes or clear them in error case.

	/* Pointer to memory does not need to be initialized, since helper function

	 * fills all bytes or clears them in error case.

	 */

	ARG_PTR_TO_UNINIT_MEM		= MEM_UNINIT | ARG_PTR_TO_MEM,

	ARG_PTR_TO_UNINIT_MEM		= MEM_UNINIT | MEM_WRITE | ARG_PTR_TO_MEM,

	/* Pointer to valid memory of size known at compile time. */

	ARG_PTR_TO_FIXED_SIZE_MEM	= MEM_FIXED_SIZE | ARG_PTR_TO_MEM,

kernel/bpf/helpers.c

+5 −5
Original line number Diff line number Diff line
@@ -110,7 +110,7 @@ const struct bpf_func_proto bpf_map_pop_elem_proto = { 
	.gpl_only	= false,

	.ret_type	= RET_INTEGER,

	.arg1_type	= ARG_CONST_MAP_PTR,

	.arg2_type	= ARG_PTR_TO_MAP_VALUE | MEM_UNINIT,

	.arg2_type	= ARG_PTR_TO_MAP_VALUE | MEM_UNINIT | MEM_WRITE,

};



BPF_CALL_2(bpf_map_peek_elem, struct bpf_map *, map, void *, value)
@@ -123,7 +123,7 @@ const struct bpf_func_proto bpf_map_peek_elem_proto = { 
	.gpl_only	= false,

	.ret_type	= RET_INTEGER,

	.arg1_type	= ARG_CONST_MAP_PTR,

	.arg2_type	= ARG_PTR_TO_MAP_VALUE | MEM_UNINIT,

	.arg2_type	= ARG_PTR_TO_MAP_VALUE | MEM_UNINIT | MEM_WRITE,

};



BPF_CALL_3(bpf_map_lookup_percpu_elem, struct bpf_map *, map, void *, key, u32, cpu)
@@ -538,7 +538,7 @@ const struct bpf_func_proto bpf_strtol_proto = { 
	.arg1_type	= ARG_PTR_TO_MEM | MEM_RDONLY,

	.arg2_type	= ARG_CONST_SIZE,

	.arg3_type	= ARG_ANYTHING,

	.arg4_type	= ARG_PTR_TO_FIXED_SIZE_MEM | MEM_UNINIT | MEM_ALIGNED,

	.arg4_type	= ARG_PTR_TO_FIXED_SIZE_MEM | MEM_UNINIT | MEM_WRITE | MEM_ALIGNED,

	.arg4_size	= sizeof(s64),

};
@@ -568,7 +568,7 @@ const struct bpf_func_proto bpf_strtoul_proto = { 
	.arg1_type	= ARG_PTR_TO_MEM | MEM_RDONLY,

	.arg2_type	= ARG_CONST_SIZE,

	.arg3_type	= ARG_ANYTHING,

	.arg4_type	= ARG_PTR_TO_FIXED_SIZE_MEM | MEM_UNINIT | MEM_ALIGNED,

	.arg4_type	= ARG_PTR_TO_FIXED_SIZE_MEM | MEM_UNINIT | MEM_WRITE | MEM_ALIGNED,

	.arg4_size	= sizeof(u64),

};
@@ -1655,7 +1655,7 @@ static const struct bpf_func_proto bpf_dynptr_from_mem_proto = { 
	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,

	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,

	.arg3_type	= ARG_ANYTHING,

	.arg4_type	= ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL | MEM_UNINIT,

	.arg4_type	= ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL | MEM_UNINIT | MEM_WRITE,

};



BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, const struct bpf_dynptr_kern *, src,

kernel/bpf/ringbuf.c

+1 −1
Original line number Diff line number Diff line
@@ -632,7 +632,7 @@ const struct bpf_func_proto bpf_ringbuf_reserve_dynptr_proto = { 
	.arg1_type	= ARG_CONST_MAP_PTR,

	.arg2_type	= ARG_ANYTHING,

	.arg3_type	= ARG_ANYTHING,

	.arg4_type	= ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_RINGBUF | MEM_UNINIT,

	.arg4_type	= ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_RINGBUF | MEM_UNINIT | MEM_WRITE,

};



BPF_CALL_2(bpf_ringbuf_submit_dynptr, struct bpf_dynptr_kern *, ptr, u64, flags)

kernel/bpf/syscall.c

+1 −1
Original line number Diff line number Diff line
@@ -5713,7 +5713,7 @@ static const struct bpf_func_proto bpf_kallsyms_lookup_name_proto = { 
	.arg1_type	= ARG_PTR_TO_MEM,

	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,

	.arg3_type	= ARG_ANYTHING,

	.arg4_type	= ARG_PTR_TO_FIXED_SIZE_MEM | MEM_UNINIT | MEM_ALIGNED,

	.arg4_type	= ARG_PTR_TO_FIXED_SIZE_MEM | MEM_UNINIT | MEM_WRITE | MEM_ALIGNED,

	.arg4_size	= sizeof(u64),

};

kernel/trace/bpf_trace.c

+2 −2
Original line number Diff line number Diff line
@@ -1220,7 +1220,7 @@ static const struct bpf_func_proto bpf_get_func_arg_proto = { 
	.ret_type	= RET_INTEGER,

	.arg1_type	= ARG_PTR_TO_CTX,

	.arg2_type	= ARG_ANYTHING,

	.arg3_type	= ARG_PTR_TO_FIXED_SIZE_MEM | MEM_UNINIT | MEM_ALIGNED,

	.arg3_type	= ARG_PTR_TO_FIXED_SIZE_MEM | MEM_UNINIT | MEM_WRITE | MEM_ALIGNED,

	.arg3_size	= sizeof(u64),

};
@@ -1237,7 +1237,7 @@ static const struct bpf_func_proto bpf_get_func_ret_proto = { 
	.func		= get_func_ret,

	.ret_type	= RET_INTEGER,

	.arg1_type	= ARG_PTR_TO_CTX,

	.arg2_type	= ARG_PTR_TO_FIXED_SIZE_MEM | MEM_UNINIT | MEM_ALIGNED,

	.arg2_type	= ARG_PTR_TO_FIXED_SIZE_MEM | MEM_UNINIT | MEM_WRITE | MEM_ALIGNED,

	.arg2_size	= sizeof(u64),

};