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authorEric Dumazet <edumazet@google.com>2015-04-24 04:03:44 +0300
committerDavid S. Miller <davem@davemloft.net>2015-04-24 18:39:15 +0300
commitb357a364c57c940ddb932224542494363df37378 (patch)
tree84657c956c5c64a2ae058b8285271f778b1aea67 /include/net/request_sock.h
parent1d8dc3d3c8f1d8ee1da9d54c5d7c8694419ade42 (diff)
downloadlinux-b357a364c57c940ddb932224542494363df37378.tar.xz
inet: fix possible panic in reqsk_queue_unlink()
[ 3897.923145] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 3897.931025] IP: [<ffffffffa9f27686>] reqsk_timer_handler+0x1a6/0x243 There is a race when reqsk_timer_handler() and tcp_check_req() call inet_csk_reqsk_queue_unlink() on the same req at the same time. Before commit fa76ce7328b2 ("inet: get rid of central tcp/dccp listener timer"), listener spinlock was held and race could not happen. To solve this bug, we change reqsk_queue_unlink() to not assume req must be found, and we return a status, to conditionally release a refcount on the request sock. This also means tcp_check_req() in non fastopen case might or not consume req refcount, so tcp_v6_hnd_req() & tcp_v4_hnd_req() have to properly handle this. (Same remark for dccp_check_req() and its callers) inet_csk_reqsk_queue_drop() is now too big to be inlined, as it is called 4 times in tcp and 3 times in dccp. Fixes: fa76ce7328b2 ("inet: get rid of central tcp/dccp listener timer") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/request_sock.h')
-rw-r--r--include/net/request_sock.h18
1 files changed, 0 insertions, 18 deletions
diff --git a/include/net/request_sock.h b/include/net/request_sock.h
index fe41f3ceb008..9f4265ce8892 100644
--- a/include/net/request_sock.h
+++ b/include/net/request_sock.h
@@ -212,24 +212,6 @@ static inline int reqsk_queue_empty(struct request_sock_queue *queue)
return queue->rskq_accept_head == NULL;
}
-static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
- struct request_sock *req)
-{
- struct listen_sock *lopt = queue->listen_opt;
- struct request_sock **prev;
-
- spin_lock(&queue->syn_wait_lock);
-
- prev = &lopt->syn_table[req->rsk_hash];
- while (*prev != req)
- prev = &(*prev)->dl_next;
- *prev = req->dl_next;
-
- spin_unlock(&queue->syn_wait_lock);
- if (del_timer(&req->rsk_timer))
- reqsk_put(req);
-}
-
static inline void reqsk_queue_add(struct request_sock_queue *queue,
struct request_sock *req,
struct sock *parent,