From 6b93c510684a802e58da9c04aa05ee3aad74d6ed Mon Sep 17 00:00:00 2001 From: Lin Ma Date: Tue, 25 Jul 2023 10:33:30 +0800 Subject: [PATCH] bpf: Add length check for SK_DIAG_BPF_STORAGE_REQ_MAP_FD parsing [ Upstream commit bcc29b7f5af6797702c2306a7aacb831fc5ce9cb ] 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 Signed-off-by: Lin Ma Reviewed-by: Jakub Kicinski Link: https://lore.kernel.org/r/20230725023330.422856-1-linma@zju.edu.cn Signed-off-by: Martin KaFai Lau Signed-off-by: Sasha Levin --- net/core/bpf_sk_storage.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index d67d06d6b817..a811fe0f0f6f 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -446,8 +446,11 @@ 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(sizeof(*diag) + sizeof(diag->maps[0]) * nr_maps,