* [PATCH v1] bpf: Add length check for SK_DIAG_BPF_STORAGE_REQ_MAP_FD parsing
@ 2023-07-23 7:54 Lin Ma
2023-07-24 22:15 ` Jakub Kicinski
0 siblings, 1 reply; 3+ messages in thread
From: Lin Ma @ 2023-07-23 7:54 UTC (permalink / raw)
To: davem, edumazet, kuba, pabeni, ast, martin.lau, yhs, andrii,
void, houtao1, laoar.shao, inwardvessel, kuniyu, netdev,
linux-kernel, bpf
Cc: Lin Ma
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@zju.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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v1] bpf: Add length check for SK_DIAG_BPF_STORAGE_REQ_MAP_FD parsing
2023-07-23 7:54 [PATCH v1] bpf: Add length check for SK_DIAG_BPF_STORAGE_REQ_MAP_FD parsing Lin Ma
@ 2023-07-24 22:15 ` Jakub Kicinski
2023-07-25 0:12 ` Lin Ma
0 siblings, 1 reply; 3+ messages in thread
From: Jakub Kicinski @ 2023-07-24 22:15 UTC (permalink / raw)
To: Lin Ma
Cc: davem, edumazet, pabeni, ast, martin.lau, yhs, andrii, void,
houtao1, laoar.shao, inwardvessel, kuniyu, netdev, linux-kernel,
bpf
On Sun, 23 Jul 2023 15:54:52 +0800 Lin Ma wrote:
> 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;
> + }
You can move this check earlier, when the attributes are getting
counted. That way we can avoid the alloc/free on error.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v1] bpf: Add length check for SK_DIAG_BPF_STORAGE_REQ_MAP_FD parsing
2023-07-24 22:15 ` Jakub Kicinski
@ 2023-07-25 0:12 ` Lin Ma
0 siblings, 0 replies; 3+ messages in thread
From: Lin Ma @ 2023-07-25 0:12 UTC (permalink / raw)
To: Jakub Kicinski
Cc: davem, edumazet, pabeni, ast, martin.lau, yhs, andrii, void,
houtao1, laoar.shao, inwardvessel, kuniyu, netdev, linux-kernel,
bpf
Hi Jakub,
>
> You can move this check earlier, when the attributes are getting
> counted. That way we can avoid the alloc/free on error.
Good point, will fix that and prepare another patch
Thanks
Lin
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-07-25 0:13 UTC | newest]
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2023-07-23 7:54 [PATCH v1] bpf: Add length check for SK_DIAG_BPF_STORAGE_REQ_MAP_FD parsing Lin Ma
2023-07-24 22:15 ` Jakub Kicinski
2023-07-25 0:12 ` Lin Ma
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