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Merge branch 'isdn-null-deref'
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Karsten Keil says:

====================
Fix potential NULL pointer access and memory leak in ISDN layer2 functions

Insu Yun did brinup the issue with not checking the skb_clone() return
value in the layer2 I-frame ull functions.
This series fix the issue in a way which avoid protocol violations/data loss
on a temporary memory shortage.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller committed Oct 22, 2015
2 parents 4ef7ea9 + c96356a commit 92a93fd
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Showing 2 changed files with 28 additions and 46 deletions.
20 changes: 8 additions & 12 deletions drivers/isdn/hisax/isdnl2.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1247,7 +1247,7 @@ static void
l2_pull_iqueue(struct FsmInst *fi, int event, void *arg)
{
struct PStack *st = fi->userdata;
struct sk_buff *skb;
struct sk_buff *skb, *nskb;
struct Layer2 *l2 = &st->l2;
u_char header[MAX_HEADER_LEN];
int i, hdr_space_needed;
Expand All @@ -1262,14 +1262,10 @@ l2_pull_iqueue(struct FsmInst *fi, int event, void *arg)
return;

hdr_space_needed = l2headersize(l2, 0);
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;
}
nskb = skb_realloc_headroom(skb, hdr_space_needed);
if (!nskb) {
skb_queue_head(&l2->i_queue, skb);
return;
}
spin_lock_irqsave(&l2->lock, flags);
if (test_bit(FLG_MOD128, &l2->flag))
Expand All @@ -1282,7 +1278,7 @@ l2_pull_iqueue(struct FsmInst *fi, int event, void *arg)
p1);
dev_kfree_skb(l2->windowar[p1]);
}
l2->windowar[p1] = skb_clone(skb, GFP_ATOMIC);
l2->windowar[p1] = skb;

i = sethdraddr(&st->l2, header, CMD);

Expand All @@ -1295,8 +1291,8 @@ l2_pull_iqueue(struct FsmInst *fi, int event, void *arg)
l2->vs = (l2->vs + 1) % 8;
}
spin_unlock_irqrestore(&l2->lock, flags);
memcpy(skb_push(skb, i), header, i);
st->l2.l2l1(st, PH_PULL | INDICATION, skb);
memcpy(skb_push(nskb, i), header, i);
st->l2.l2l1(st, PH_PULL | INDICATION, nskb);
test_and_clear_bit(FLG_ACK_PEND, &st->l2.flag);
if (!test_and_set_bit(FLG_T200_RUN, &st->l2.flag)) {
FsmDelTimer(&st->l2.t203, 13);
Expand Down
54 changes: 20 additions & 34 deletions drivers/isdn/mISDN/layer2.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1476,7 +1476,7 @@ static void
l2_pull_iqueue(struct FsmInst *fi, int event, void *arg)
{
struct layer2 *l2 = fi->userdata;
struct sk_buff *skb, *nskb, *oskb;
struct sk_buff *skb, *nskb;
u_char header[MAX_L2HEADER_LEN];
u_int i, p1;

Expand All @@ -1486,48 +1486,34 @@ l2_pull_iqueue(struct FsmInst *fi, int event, void *arg)
skb = skb_dequeue(&l2->i_queue);
if (!skb)
return;

if (test_bit(FLG_MOD128, &l2->flag))
p1 = (l2->vs - l2->va) % 128;
else
p1 = (l2->vs - l2->va) % 8;
p1 = (p1 + l2->sow) % l2->window;
if (l2->windowar[p1]) {
printk(KERN_WARNING "%s: l2 try overwrite ack queue entry %d\n",
mISDNDevName4ch(&l2->ch), p1);
dev_kfree_skb(l2->windowar[p1]);
}
l2->windowar[p1] = skb;
i = sethdraddr(l2, header, CMD);
if (test_bit(FLG_MOD128, &l2->flag)) {
header[i++] = l2->vs << 1;
header[i++] = l2->vr << 1;
} else
header[i++] = (l2->vr << 5) | (l2->vs << 1);
nskb = skb_realloc_headroom(skb, i);
if (!nskb) {
printk(KERN_WARNING "%s: no headroom(%d) copy for IFrame\n",
mISDNDevName4ch(&l2->ch), i);
skb_queue_head(&l2->i_queue, skb);
return;
}
if (test_bit(FLG_MOD128, &l2->flag)) {
p1 = (l2->vs - l2->va) % 128;
l2->vs = (l2->vs + 1) % 128;
} else {
header[i++] = (l2->vr << 5) | (l2->vs << 1);
p1 = (l2->vs - l2->va) % 8;
l2->vs = (l2->vs + 1) % 8;
}

nskb = skb_clone(skb, GFP_ATOMIC);
p1 = skb_headroom(nskb);
if (p1 >= i)
memcpy(skb_push(nskb, i), header, i);
else {
printk(KERN_WARNING
"%s: L2 pull_iqueue skb header(%d/%d) too short\n",
mISDNDevName4ch(&l2->ch), i, p1);
oskb = nskb;
nskb = mI_alloc_skb(oskb->len + i, GFP_ATOMIC);
if (!nskb) {
dev_kfree_skb(oskb);
printk(KERN_WARNING "%s: no skb mem in %s\n",
mISDNDevName4ch(&l2->ch), __func__);
return;
}
memcpy(skb_put(nskb, i), header, i);
memcpy(skb_put(nskb, oskb->len), oskb->data, oskb->len);
dev_kfree_skb(oskb);
p1 = (p1 + l2->sow) % l2->window;
if (l2->windowar[p1]) {
printk(KERN_WARNING "%s: l2 try overwrite ack queue entry %d\n",
mISDNDevName4ch(&l2->ch), p1);
dev_kfree_skb(l2->windowar[p1]);
}
l2->windowar[p1] = skb;
memcpy(skb_push(nskb, i), header, i);
l2down(l2, PH_DATA_REQ, l2_newid(l2), nskb);
test_and_clear_bit(FLG_ACK_PEND, &l2->flag);
if (!test_and_set_bit(FLG_T200_RUN, &l2->flag)) {
Expand Down

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