diff options
| author | Krzysztof Mazur <krzysiek@podlesie.net> | 2012-11-06 23:17:00 +0100 |
|---|---|---|
| committer | David Woodhouse <David.Woodhouse@intel.com> | 2012-11-28 00:37:05 +0000 |
| commit | 3ac108006fd7f20cb8fc8ea2287f1497bcda00a1 (patch) | |
| tree | 4931009972256abde839087b795c7b9b4926ae36 /net/atm | |
| parent | e41faed9cde1acce657f75a0b19a1787e9850d3f (diff) | |
| download | lwn-3ac108006fd7f20cb8fc8ea2287f1497bcda00a1.tar.gz lwn-3ac108006fd7f20cb8fc8ea2287f1497bcda00a1.zip | |
pppoatm: take ATM socket lock in pppoatm_send()
The pppoatm_send() does not take any lock that will prevent concurrent
vcc_sendmsg(). This causes two problems:
- there is no locking between checking the send queue size
with atm_may_send() and incrementing sk_wmem_alloc,
and the real queue size can be a little higher than sk_sndbuf
- the vcc->sendmsg() can be called concurrently. I'm not sure
if it's allowed. Some drivers (eni, nicstar, ...) seem
to assume it will never happen.
Now pppoatm_send() takes ATM socket lock, the same that is used
in vcc_sendmsg() and other ATM socket functions. The pppoatm_send()
is called with BH disabled, so bh_lock_sock() is used instead
of lock_sock().
Signed-off-by: Krzysztof Mazur <krzysiek@podlesie.net>
Cc: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Diffstat (limited to 'net/atm')
| -rw-r--r-- | net/atm/pppoatm.c | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/net/atm/pppoatm.c b/net/atm/pppoatm.c index b23c6723e87c..c4a57bca77bf 100644 --- a/net/atm/pppoatm.c +++ b/net/atm/pppoatm.c @@ -272,10 +272,19 @@ static inline int pppoatm_may_send(struct pppoatm_vcc *pvcc, int size) static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb) { struct pppoatm_vcc *pvcc = chan_to_pvcc(chan); + struct atm_vcc *vcc; + int ret; + ATM_SKB(skb)->vcc = pvcc->atmvcc; pr_debug("(skb=0x%p, vcc=0x%p)\n", skb, pvcc->atmvcc); if (skb->data[0] == '\0' && (pvcc->flags & SC_COMP_PROT)) (void) skb_pull(skb, 1); + + vcc = ATM_SKB(skb)->vcc; + bh_lock_sock(sk_atm(vcc)); + if (sock_owned_by_user(sk_atm(vcc))) + goto nospace; + switch (pvcc->encaps) { /* LLC encapsulation needed */ case e_llc: if (skb_headroom(skb) < LLC_LEN) { @@ -288,8 +297,10 @@ static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb) } consume_skb(skb); skb = n; - if (skb == NULL) + if (skb == NULL) { + bh_unlock_sock(sk_atm(vcc)); return DROP_PACKET; + } } else if (!pppoatm_may_send(pvcc, skb->truesize)) goto nospace; memcpy(skb_push(skb, LLC_LEN), pppllc, LLC_LEN); @@ -299,6 +310,7 @@ static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb) goto nospace; break; case e_autodetect: + bh_unlock_sock(sk_atm(vcc)); pr_debug("Trying to send without setting encaps!\n"); kfree_skb(skb); return 1; @@ -308,9 +320,12 @@ static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb) ATM_SKB(skb)->atm_options = ATM_SKB(skb)->vcc->atm_options; pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, ATM_SKB(skb)->vcc, ATM_SKB(skb)->vcc->dev); - return ATM_SKB(skb)->vcc->send(ATM_SKB(skb)->vcc, skb) + ret = ATM_SKB(skb)->vcc->send(ATM_SKB(skb)->vcc, skb) ? DROP_PACKET : 1; + bh_unlock_sock(sk_atm(vcc)); + return ret; nospace: + bh_unlock_sock(sk_atm(vcc)); /* * We don't have space to send this SKB now, but we might have * already applied SC_COMP_PROT compression, so may need to undo |