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authorOr Cohen <orcohen@paloaltonetworks.com>2021-05-04 10:16:46 +0300
committerDavid S. Miller <davem@davemloft.net>2021-05-04 11:59:48 -0700
commitc61760e6940dd4039a7f5e84a6afc9cdbf4d82b6 (patch)
tree0ae6e50851a6391c28f3be771193357c50d575b1
parent8d432592f30fcc34ef5a10aac4887b4897884493 (diff)
net/nfc: fix use-after-free llcp_sock_bind/connect
Commits 8a4cd82d ("nfc: fix refcount leak in llcp_sock_connect()") and c33b1cc62 ("nfc: fix refcount leak in llcp_sock_bind()") fixed a refcount leak bug in bind/connect but introduced a use-after-free if the same local is assigned to 2 different sockets. This can be triggered by the following simple program: int sock1 = socket( AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP ); int sock2 = socket( AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP ); memset( &addr, 0, sizeof(struct sockaddr_nfc_llcp) ); addr.sa_family = AF_NFC; addr.nfc_protocol = NFC_PROTO_NFC_DEP; bind( sock1, (struct sockaddr*) &addr, sizeof(struct sockaddr_nfc_llcp) ) bind( sock2, (struct sockaddr*) &addr, sizeof(struct sockaddr_nfc_llcp) ) close(sock1); close(sock2); Fix this by assigning NULL to llcp_sock->local after calling nfc_llcp_local_put. This addresses CVE-2021-23134. Reported-by: Or Cohen <orcohen@paloaltonetworks.com> Reported-by: Nadav Markus <nmarkus@paloaltonetworks.com> Fixes: c33b1cc62 ("nfc: fix refcount leak in llcp_sock_bind()") Signed-off-by: Or Cohen <orcohen@paloaltonetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/nfc/llcp_sock.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/nfc/llcp_sock.c b/net/nfc/llcp_sock.c
index a3b46f888803..53dbe733f998 100644
--- a/net/nfc/llcp_sock.c
+++ b/net/nfc/llcp_sock.c
@@ -109,12 +109,14 @@ static int llcp_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
GFP_KERNEL);
if (!llcp_sock->service_name) {
nfc_llcp_local_put(llcp_sock->local);
+ llcp_sock->local = NULL;
ret = -ENOMEM;
goto put_dev;
}
llcp_sock->ssap = nfc_llcp_get_sdp_ssap(local, llcp_sock);
if (llcp_sock->ssap == LLCP_SAP_MAX) {
nfc_llcp_local_put(llcp_sock->local);
+ llcp_sock->local = NULL;
kfree(llcp_sock->service_name);
llcp_sock->service_name = NULL;
ret = -EADDRINUSE;
@@ -709,6 +711,7 @@ static int llcp_sock_connect(struct socket *sock, struct sockaddr *_addr,
llcp_sock->ssap = nfc_llcp_get_local_ssap(local);
if (llcp_sock->ssap == LLCP_SAP_MAX) {
nfc_llcp_local_put(llcp_sock->local);
+ llcp_sock->local = NULL;
ret = -ENOMEM;
goto put_dev;
}
@@ -756,6 +759,7 @@ sock_unlink:
sock_llcp_release:
nfc_llcp_put_ssap(local, llcp_sock->ssap);
nfc_llcp_local_put(llcp_sock->local);
+ llcp_sock->local = NULL;
put_dev:
nfc_put_device(dev);