[12/16] NFC: llcp: fix info leaks via msg_name in llcp_sock_recvmsg()

Submitted by Mathias Krause on April 7, 2013, 11:51 a.m.


Message ID 1365335522-29931-13-git-send-email-minipli@googlemail.com
State Accepted
Delegated to: David Miller
Headers show

Commit Message

Mathias Krause April 7, 2013, 11:51 a.m.
The code in llcp_sock_recvmsg() does not initialize all the members of
struct sockaddr_nfc_llcp when filling the sockaddr info. Nor does it
initialize the padding bytes of the structure inserted by the compiler
for alignment.

Also, if the socket is in state LLCP_CLOSED or is shutting down during
receive the msg_namelen member is not updated to 0 while otherwise
returning with 0, i.e. "success". The msg_namelen update is also
missing for stream and seqpacket sockets which don't fill the sockaddr

Both issues lead to the fact that the code will leak uninitialized
kernel stack bytes in net/socket.c.

Fix the first issue by initializing the memory used for sockaddr info
with memset(0). Fix the second one by setting msg_namelen to 0 early.
It will be updated later if we're going to fill the msg_name member.

Cc: Lauro Ramos Venancio <lauro.venancio@openbossa.org>
Cc: Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Mathias Krause <minipli@googlemail.com>
 net/nfc/llcp/sock.c |    3 +++
 1 file changed, 3 insertions(+)

Patch hide | download patch | download mbox

diff --git a/net/nfc/llcp/sock.c b/net/nfc/llcp/sock.c
index 5c7cdf3..4741adc 100644
--- a/net/nfc/llcp/sock.c
+++ b/net/nfc/llcp/sock.c
@@ -646,6 +646,8 @@  static int llcp_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
 	pr_debug("%p %zu\n", sk, len);
+	msg->msg_namelen = 0;
 	if (sk->sk_state == LLCP_CLOSED &&
@@ -691,6 +693,7 @@  static int llcp_sock_recvmsg(struct kiocb *iocb, struct socket *sock,
 		pr_debug("Datagram socket %d %d\n", ui_cb->dsap, ui_cb->ssap);
+		memset(sockaddr, 0, sizeof(*sockaddr));
 		sockaddr->sa_family = AF_NFC;
 		sockaddr->nfc_protocol = NFC_PROTO_NFC_DEP;
 		sockaddr->dsap = ui_cb->dsap;