A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-29 03:01:39 -04:00
Code Issues Projects Releases Packages Wiki Activity

inet: fix possible panic in reqsk_queue_unlink()

Browse source 
[ 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 fa76ce7328 ("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: fa76ce7328 ("inet: get rid of central tcp/dccp listener timer")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: Yuchung Cheng <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
This commit is contained in:
Eric Dumazet 2015-04-23 18:03:44 -07:00 • committed by David S. Miller
commit b357a364c5
9 changed files with 48 additions and 46 deletions
Download patch file Download diff file Expand all files Collapse all files

20
include/net/inet_connection_sock.h
View file

@ -279,12 +279,6 @@ static inline void inet_csk_reqsk_queue_add(struct sock *sk,
void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
unsigned long timeout);
static inline void inet_csk_reqsk_queue_removed(struct sock *sk,
struct request_sock *req)
{
reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
}
static inline void inet_csk_reqsk_queue_added(struct sock *sk,
const unsigned long timeout)
{
@ -306,19 +300,7 @@ static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
return reqsk_queue_is_full(&inet_csk(sk)->icsk_accept_queue);
}
static inline void inet_csk_reqsk_queue_unlink(struct sock *sk,
struct request_sock *req)
{
reqsk_queue_unlink(&inet_csk(sk)->icsk_accept_queue, req);
}
static inline void inet_csk_reqsk_queue_drop(struct sock *sk,
struct request_sock *req)
{
inet_csk_reqsk_queue_unlink(sk, req);
inet_csk_reqsk_queue_removed(sk, req);
reqsk_put(req);
}
void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);
void inet_csk_destroy_sock(struct sock *sk);
void inet_csk_prepare_forced_close(struct sock *sk);

18
include/net/request_sock.h
View file

@ -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,