linux-kernel - [PATCH bpf 1/2] bpf: Do not copy spin lock field from user in bpf_selem

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Date:   Mon, 14 Nov 2022 08:47:19 -0500
From:   Xu Kuohai <xukuohai@...wei.com>
To:     <bpf@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-kselftest@...r.kernel.org>
CC:     Martin KaFai Lau <martin.lau@...ux.dev>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Song Liu <song@...nel.org>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>,
        Stanislav Fomichev <sdf@...gle.com>,
        Hao Luo <haoluo@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
        Kumar Kartikeya Dwivedi <memxor@...il.com>,
        Mykola Lysenko <mykolal@...com>, Shuah Khan <shuah@...nel.org>
Subject: [PATCH bpf 1/2] bpf: Do not copy spin lock field from user in bpf_selem_alloc

bpf_selem_alloc function is used by inode_storage, sk_storage and
task_storage maps to set map value, for these map types, there may
be a spin lock in the map value, so if we use memcpy to copy the whole
map value from user, the spin lock field may be initialized incorrectly.

Since the spin lock field is zeroed by kzalloc, call copy_map_value
instead of memcpy to skip copying the spin lock field to fix it.

Fixes: 6ac99e8f23d4 ("bpf: Introduce bpf sk local storage")
Signed-off-by: Xu Kuohai <xukuohai@...wei.com>
---
 kernel/bpf/bpf_local_storage.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index 802fc15b0d73..f27fa5ba7d72 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -74,7 +74,7 @@ bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner,
 				gfp_flags | __GFP_NOWARN);
 	if (selem) {
 		if (value)
-			memcpy(SDATA(selem)->data, value, smap->map.value_size);
+			copy_map_value(&smap->map, SDATA(selem)->data, value);
 		return selem;
 	}
 
-- 
2.30.2