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bpf: Add length check for SK_DIAG_BPF_STORAGE_REQ_MAP_FD parsing

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The nla_for_each_nested parsing in function bpf_sk_storage_diag_alloc
does not check the length of the nested attribute. This can lead to an
out-of-attribute read and allow a malformed nlattr (e.g., length 0) to
be viewed as a 4 byte integer.

This patch adds an additional check when the nlattr is getting counted.
This makes sure the latter nla_get_u32 can access the attributes with
the correct length.

Fixes: 1ed4d92458 ("bpf: INET_DIAG support in bpf_sk_storage")
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20230725023330.422856-1-linma@zju.edu.cn
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
This commit is contained in:
Lin Ma 2023-07-25 10:33:30 +08:00 committed by Martin KaFai Lau
parent aa89592fcb
commit bcc29b7f5a
1 changed files with 4 additions and 1 deletions
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5
net/core/bpf_sk_storage.c
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@ -496,8 +496,11 @@ bpf_sk_storage_diag_alloc(const struct nlattr *nla_stgs)
return ERR_PTR(-EPERM);
nla_for_each_nested(nla, nla_stgs, rem) {
if (nla_type(nla) == SK_DIAG_BPF_STORAGE_REQ_MAP_FD)
if (nla_type(nla) == SK_DIAG_BPF_STORAGE_REQ_MAP_FD) {
if (nla_len(nla) != sizeof(u32))
return ERR_PTR(-EINVAL);
nr_maps++;
}
}
diag = kzalloc(struct_size(diag, maps, nr_maps), GFP_KERNEL);