diff options
| author | Lin Ma <linma@zju.edu.cn> | 2023-07-25 10:33:30 +0800 |
|---|---|---|
| committer | Martin KaFai Lau <martin.lau@kernel.org> | 2023-07-27 10:07:56 -0700 |
| commit | bcc29b7f5af6797702c2306a7aacb831fc5ce9cb (patch) | |
| tree | b43e787ddb59ae737914e81c25a40c4cf528818b /net | |
| parent | aa89592fcb3af8372bd39ff468fdd65477f57201 (diff) | |
| download | lwn-bcc29b7f5af6797702c2306a7aacb831fc5ce9cb.tar.gz lwn-bcc29b7f5af6797702c2306a7aacb831fc5ce9cb.zip | |
bpf: Add length check for SK_DIAG_BPF_STORAGE_REQ_MAP_FD parsing
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: 1ed4d92458a9 ("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>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/bpf_sk_storage.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index d4172534dfa8..cca7594be92e 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -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); |