[SRU Impish 1/1] af_key: add __GFP_ZERO flag for compose_sadb_supported in function pfkey_register

Thadeu Lima de Souza Cascardo cascardo at canonical.com
Fri Jun 24 12:30:35 UTC 2022

From: Haimin Zhang <tcs_kernel at tencent.com>

Add __GFP_ZERO flag for compose_sadb_supported in function pfkey_register
to initialize the buffer of supp_skb to fix a kernel-info-leak issue.
1) Function pfkey_register calls compose_sadb_supported to request
a sk_buff. 2) compose_sadb_supported calls alloc_sbk to allocate
a sk_buff, but it doesn't zero it. 3) If auth_len is greater 0, then
compose_sadb_supported treats the memory as a struct sadb_supported and
begins to initialize. But it just initializes the field sadb_supported_len
and field sadb_supported_exttype without field sadb_supported_reserved.

Reported-by: TCS Robot <tcs_robot at tencent.com>
Signed-off-by: Haimin Zhang <tcs_kernel at tencent.com>
Signed-off-by: Steffen Klassert <steffen.klassert at secunet.com>
(cherry picked from commit 9a564bccb78a76740ea9d75a259942df8143d02c)
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo at canonical.com>
 net/key/af_key.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/key/af_key.c b/net/key/af_key.c
index ef9b4ac03e7b..b95684b8903e 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -1703,7 +1703,7 @@ static int pfkey_register(struct sock *sk, struct sk_buff *skb, const struct sad
-	supp_skb = compose_sadb_supported(hdr, GFP_KERNEL);
+	supp_skb = compose_sadb_supported(hdr, GFP_KERNEL | __GFP_ZERO);
 	if (!supp_skb) {
 		if (hdr->sadb_msg_satype != SADB_SATYPE_UNSPEC)
 			pfk->registered &= ~(1<<hdr->sadb_msg_satype);

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