[ 09/80] inet_diag: fix oops for IPv4 AF_INET6 TCP SYN-RECV state

Greg Kroah-Hartman
2013-01-09T21:46:11Z

From: Neal Cardwell <ncardwell@google.com>

[ Upstream commit 1c95df85ca49640576de2f0a850925957b547b84 ]

Fix inet_diag to be aware of the fact that AF_INET6 TCP connections
instantiated for IPv4 traffic and in the SYN-RECV state were actually
created with inet_reqsk_alloc(), instead of inet6_reqsk_alloc(). This
means that for such connections inet6_rsk(req) returns a pointer to a
random spot in memory up to roughly 64KB beyond the end of the
request_sock.

With this bug, for a server using AF_INET6 TCP sockets and serving
IPv4 traffic, an inet_diag user like `ss state SYN-RECV` would lead to
inet_diag_fill_req() causing an oops or the export to user space of 16
bytes of kernel memory as a garbage IPv6 address, depending on where
the garbage inet6_rsk(req) pointed.

Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/inet_diag.c | 53 +++++++++++++++++++++++++++++++++++++--------------
1 file changed, 39 insertions(+), 14 deletions(-)

--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -44,6 +44,10 @@ struct inet_diag_entry {
u16 dport;
u16 family;
u16 userlocks;
+#if IS_ENABLED(CONFIG_IPV6)
+ struct in6_addr saddr_storage; /* for IPv4-mapped-IPv6 addresses */
+ struct in6_addr daddr_storage; /* for IPv4-mapped-IPv6 addresses */
+#endif
};

#define INET_DIAG_PUT(skb, attrtype, attrlen) \
@@ -586,6 +590,36 @@ static int inet_twsk_diag_dump(struct in
cb->nlh->nlmsg_seq, NLM_F_MULTI, cb->nlh);
}

+/* Get the IPv4, IPv6, or IPv4-mapped-IPv6 local and remote addresses
+ * from a request_sock. For IPv4-mapped-IPv6 we must map IPv4 to IPv6.
+ */
+static inline void inet_diag_req_addrs(const struct sock *sk,
+ const struct request_sock *req,
+ struct inet_diag_entry *entry)
+{
+ struct inet_request_sock *ireq = inet_rsk(req);
+
+#if IS_ENABLED(CONFIG_IPV6)
+ if (sk->sk_family == AF_INET6) {
+ if (req->rsk_ops->family == AF_INET6) {
+ entry->saddr = inet6_rsk(req)->loc_addr.s6_addr32;
+ entry->daddr = inet6_rsk(req)->rmt_addr.s6_addr32;
+ } else if (req->rsk_ops->family == AF_INET) {
+ ipv6_addr_set_v4mapped(ireq->loc_addr,
+ &entry->saddr_storage);
+ ipv6_addr_set_v4mapped(ireq->rmt_addr,
+ &entry->daddr_storage);
+ entry->saddr = entry->saddr_storage.s6_addr32;
+ entry->daddr = entry->daddr_storage.s6_addr32;
+ }
+ } else
+#endif
+ {
+ entry->saddr = &ireq->loc_addr;
+ entry->daddr = &ireq->rmt_addr;
+ }
+}
+
static int inet_diag_fill_req(struct sk_buff *skb, struct sock *sk,
struct request_sock *req, u32 pid, u32 seq,
const struct nlmsghdr *unlh)
@@ -624,8 +658,10 @@ static int inet_diag_fill_req(struct sk_
r->idiag_inode = 0;
#if IS_ENABLED(CONFIG_IPV6)
if (r->idiag_family == AF_INET6) {
- *(struct in6_addr *)r->id.idiag_src = inet6_rsk(req)->loc_addr;
- *(struct in6_addr *)r->id.idiag_dst = inet6_rsk(req)->rmt_addr;
+ struct inet_diag_entry entry;
+ inet_diag_req_addrs(sk, req, &entry);
+ memcpy(r->id.idiag_src, entry.saddr, sizeof(struct in6_addr));
+ memcpy(r->id.idiag_dst, entry.daddr, sizeof(struct in6_addr));
}
#endif
nlh->nlmsg_len = skb_tail_pointer(skb) - b;
@@ -683,18 +719,7 @@ static int inet_diag_dump_reqs(struct sk
continue;

if (bc) {
- entry.saddr =
-#if IS_ENABLED(CONFIG_IPV6)
- (entry.family == AF_INET6) ?
- inet6_rsk(req)->loc_addr.s6_addr32 :
-#endif
- &ireq->loc_addr;
- entry.daddr =
-#if IS_ENABLED(CONFIG_IPV6)
- (entry.family == AF_INET6) ?
- inet6_rsk(req)->rmt_addr.s6_addr32 :
-#endif
- &ireq->rmt_addr;
+ inet_diag_req_addrs(sk, req, &entry);
entry.dport = ntohs(ireq->rmt_port);

if (!inet_diag_bc_run(bc, &entry))