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Message-ID: <20180111113746.28186-4-steffen.klassert@secunet.com>
Date: Thu, 11 Jan 2018 12:37:38 +0100
From: Steffen Klassert <steffen.klassert@...unet.com>
To: David Miller <davem@...emloft.net>
CC: Herbert Xu <herbert@...dor.apana.org.au>,
Steffen Klassert <steffen.klassert@...unet.com>,
<netdev@...r.kernel.org>
Subject: [PATCH 03/11] af_key: fix buffer overread in verify_address_len()
From: Eric Biggers <ebiggers@...gle.com>
If a message sent to a PF_KEY socket ended with one of the extensions
that takes a 'struct sadb_address' but there were not enough bytes
remaining in the message for the ->sa_family member of the 'struct
sockaddr' which is supposed to follow, then verify_address_len() read
past the end of the message, into uninitialized memory. Fix it by
returning -EINVAL in this case.
This bug was found using syzkaller with KMSAN.
Reproducer:
#include <linux/pfkeyv2.h>
#include <sys/socket.h>
#include <unistd.h>
int main()
{
int sock = socket(PF_KEY, SOCK_RAW, PF_KEY_V2);
char buf[24] = { 0 };
struct sadb_msg *msg = (void *)buf;
struct sadb_address *addr = (void *)(msg + 1);
msg->sadb_msg_version = PF_KEY_V2;
msg->sadb_msg_type = SADB_DELETE;
msg->sadb_msg_len = 3;
addr->sadb_address_len = 1;
addr->sadb_address_exttype = SADB_EXT_ADDRESS_SRC;
write(sock, buf, 24);
}
Reported-by: Alexander Potapenko <glider@...gle.com>
Cc: stable@...r.kernel.org
Signed-off-by: Eric Biggers <ebiggers@...gle.com>
Signed-off-by: Steffen Klassert <steffen.klassert@...unet.com>
---
net/key/af_key.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/net/key/af_key.c b/net/key/af_key.c
index 3dffb892d52c..596499cc8b2f 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -401,6 +401,11 @@ static int verify_address_len(const void *p)
#endif
int len;
+ if (sp->sadb_address_len <
+ DIV_ROUND_UP(sizeof(*sp) + offsetofend(typeof(*addr), sa_family),
+ sizeof(uint64_t)))
+ return -EINVAL;
+
switch (addr->sa_family) {
case AF_INET:
len = DIV_ROUND_UP(sizeof(*sp) + sizeof(*sin), sizeof(uint64_t));
--
2.14.1
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