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authorDaniel Borkmann <daniel@iogearbox.net>2024-10-21 17:28:05 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2024-11-01 01:58:30 +0100
commit8a33a047bd31a7047b8dffe688c2c10e1ab871eb (patch)
tree50e8b9c836a91d88f0b0603eaafcf9108d6f3889 /kernel/bpf/helpers.c
parentd1100acab464e054cbd056aac0e24b790926f18d (diff)
bpf: Add MEM_WRITE attribute
[ 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: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20241021152809.33343-1-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov <ast@kernel.org> Stable-dep-of: 8ea607330a39 ("bpf: Fix overloading of MEM_UNINIT's meaning") Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel/bpf/helpers.c')
-rw-r--r--kernel/bpf/helpers.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 3dba5bb294d8..41d62405c852 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -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),
};
@@ -1607,7 +1607,7 @@ 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,