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Message-Id: <20230723075452.3711158-1-linma@zju.edu.cn>
Date: Sun, 23 Jul 2023 15:54:52 +0800
From: Lin Ma <linma@....edu.cn>
To: davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
pabeni@...hat.com, ast@...nel.org, martin.lau@...nel.org,
yhs@...com, andrii@...nel.org, void@...ifault.com,
houtao1@...wei.com, laoar.shao@...il.com, inwardvessel@...il.com,
kuniyu@...zon.com, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, bpf@...r.kernel.org
Cc: Lin Ma <linma@....edu.cn>
Subject: [PATCH v1] 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 additional check before the execution of nla_get_u32 to
make sure the attribute has enough length.
Fixes: 1ed4d92458a9 ("bpf: INET_DIAG support in bpf_sk_storage")
Signed-off-by: Lin Ma <linma@....edu.cn>
---
net/core/bpf_sk_storage.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index d4172534dfa8..6f1afbb394a6 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -511,6 +511,11 @@ bpf_sk_storage_diag_alloc(const struct nlattr *nla_stgs)
if (nla_type(nla) != SK_DIAG_BPF_STORAGE_REQ_MAP_FD)
continue;
+ if (nla_len(nla) < sizeof(map_fd)) {
+ err = -EINVAL;
+ goto err_free;
+ }
+
map_fd = nla_get_u32(nla);
map = bpf_map_get(map_fd);
if (IS_ERR(map)) {
--
2.17.1
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