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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>
This commit is contained in:
David S. Miller 2011-02-13 16:50:45 -08:00
parent ab60707ffe
commit c978e7bb77
1 changed files with 20 additions and 15 deletions
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35
drivers/isdn/hisax/isdnl2.c
View File

@ -1243,14 +1243,21 @@ l2_st7_tout_203(struct FsmInst *fi, int event, void *arg)
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 @@ l2_pull_iqueue(struct FsmInst *fi, int event, void *arg)
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_pull_iqueue(struct FsmInst *fi, int event, void *arg)
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)) {