hisax: Fix unchecked alloc_skb() return.
Jesper Juhl noticed that l2_pull_iqueue() does not
check to see if alloc_skb() fails.
Fix this by first trying to reallocate the headroom
if necessary, rather than later after we've made hard
to undo state changes.
Reported-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/isdn/hisax/isdnl2.c b/drivers/isdn/hisax/isdnl2.c
index 0858791..98ac835 100644
--- a/drivers/isdn/hisax/isdnl2.c
+++ b/drivers/isdn/hisax/isdnl2.c
@@ -1243,14 +1243,21 @@
st->l2.rc = 0;
}
+static int l2_hdr_space_needed(struct Layer2 *l2)
+{
+ int len = test_bit(FLG_LAPD, &l2->flag) ? 2 : 1;
+
+ return len + (test_bit(FLG_LAPD, &l2->flag) ? 2 : 1);
+}
+
static void
l2_pull_iqueue(struct FsmInst *fi, int event, void *arg)
{
struct PStack *st = fi->userdata;
- struct sk_buff *skb, *oskb;
+ struct sk_buff *skb;
struct Layer2 *l2 = &st->l2;
u_char header[MAX_HEADER_LEN];
- int i;
+ int i, hdr_space_needed;
int unsigned p1;
u_long flags;
@@ -1261,6 +1268,16 @@
if (!skb)
return;
+ hdr_space_needed = l2_hdr_space_needed(l2);
+ if (hdr_space_needed > skb_headroom(skb)) {
+ struct sk_buff *orig_skb = skb;
+
+ skb = skb_realloc_headroom(skb, hdr_space_needed);
+ if (!skb) {
+ dev_kfree_skb(orig_skb);
+ return;
+ }
+ }
spin_lock_irqsave(&l2->lock, flags);
if(test_bit(FLG_MOD128, &l2->flag))
p1 = (l2->vs - l2->va) % 128;
@@ -1285,19 +1302,7 @@
l2->vs = (l2->vs + 1) % 8;
}
spin_unlock_irqrestore(&l2->lock, flags);
- p1 = skb->data - skb->head;
- if (p1 >= i)
- memcpy(skb_push(skb, i), header, i);
- else {
- printk(KERN_WARNING
- "isdl2 pull_iqueue skb header(%d/%d) too short\n", i, p1);
- oskb = skb;
- skb = alloc_skb(oskb->len + i, GFP_ATOMIC);
- memcpy(skb_put(skb, i), header, i);
- skb_copy_from_linear_data(oskb,
- skb_put(skb, oskb->len), oskb->len);
- dev_kfree_skb(oskb);
- }
+ memcpy(skb_push(skb, i), header, i);
st->l2.l2l1(st, PH_PULL | INDICATION, skb);
test_and_clear_bit(FLG_ACK_PEND, &st->l2.flag);
if (!test_and_set_bit(FLG_T200_RUN, &st->l2.flag)) {