[PATCH 3.18 07/52] af_key: fix buffer overread in parse_exthdrs()
From: Greg Kroah-Hartman
Date: Mon Jan 29 2018 - 15:39:50 EST
3.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Biggers <ebiggers@xxxxxxxxxx>
commit 4e765b4972af7b07adcb1feb16e7a525ce1f6b28 upstream.
If a message sent to a PF_KEY socket ended with an incomplete extension
header (fewer than 4 bytes remaining), then parse_exthdrs() read past
the end of the message, into uninitialized memory. Fix it by returning
-EINVAL in this case.
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[17] = { 0 };
struct sadb_msg *msg = (void *)buf;
msg->sadb_msg_version = PF_KEY_V2;
msg->sadb_msg_type = SADB_DELETE;
msg->sadb_msg_len = 2;
write(sock, buf, 17);
}
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/key/af_key.c | 3 +++
1 file changed, 3 insertions(+)
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -516,6 +516,9 @@ static int parse_exthdrs(struct sk_buff
uint16_t ext_type;
int ext_len;
+ if (len < sizeof(*ehdr))
+ return -EINVAL;
+
ext_len = ehdr->sadb_ext_len;
ext_len *= sizeof(uint64_t);
ext_type = ehdr->sadb_ext_type;