From: Eric Biggers ebiggers@google.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@google.com Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers ebiggers@google.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));