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authorChangli Gao <xiaosuo@gmail.com>2010-06-02 07:32:42 -0700
committerDavid S. Miller <davem@davemloft.net>2010-06-02 07:32:42 -0700
commitfbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d (patch)
treea82f11f0ea06fd465393314d0f37772f715c6caf /net
parentedafe502404f3669d364b6e96d79b54067b634b4 (diff)
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cls_u32: use skb_header_pointer() to dereference data safely
use skb_header_pointer() to dereference data safely the original skb->data dereference isn't safe, as there isn't any skb->len or skb_is_nonlinear() check. skb_header_pointer() is used instead in this patch. And when the skb isn't long enough, we terminate the function u32_classify() immediately with -1. Signed-off-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/sched/cls_u32.c49
1 files changed, 36 insertions, 13 deletions
diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 96275422c61..4f522143811 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -98,11 +98,11 @@ static int u32_classify(struct sk_buff *skb, struct tcf_proto *tp, struct tcf_re
{
struct {
struct tc_u_knode *knode;
- u8 *ptr;
+ unsigned int off;
} stack[TC_U32_MAXDEPTH];
struct tc_u_hnode *ht = (struct tc_u_hnode*)tp->root;
- u8 *ptr = skb_network_header(skb);
+ unsigned int off = skb_network_offset(skb);
struct tc_u_knode *n;
int sdepth = 0;
int off2 = 0;
@@ -134,8 +134,14 @@ next_knode:
#endif
for (i = n->sel.nkeys; i>0; i--, key++) {
-
- if ((*(__be32*)(ptr+key->off+(off2&key->offmask))^key->val)&key->mask) {
+ unsigned int toff;
+ __be32 *data, _data;
+
+ toff = off + key->off + (off2 & key->offmask);
+ data = skb_header_pointer(skb, toff, 4, &_data);
+ if (!data)
+ goto out;
+ if ((*data ^ key->val) & key->mask) {
n = n->next;
goto next_knode;
}
@@ -174,29 +180,45 @@ check_terminal:
if (sdepth >= TC_U32_MAXDEPTH)
goto deadloop;
stack[sdepth].knode = n;
- stack[sdepth].ptr = ptr;
+ stack[sdepth].off = off;
sdepth++;
ht = n->ht_down;
sel = 0;
- if (ht->divisor)
- sel = ht->divisor&u32_hash_fold(*(__be32*)(ptr+n->sel.hoff), &n->sel,n->fshift);
-
+ if (ht->divisor) {
+ __be32 *data, _data;
+
+ data = skb_header_pointer(skb, off + n->sel.hoff, 4,
+ &_data);
+ if (!data)
+ goto out;
+ sel = ht->divisor & u32_hash_fold(*data, &n->sel,
+ n->fshift);
+ }
if (!(n->sel.flags&(TC_U32_VAROFFSET|TC_U32_OFFSET|TC_U32_EAT)))
goto next_ht;
if (n->sel.flags&(TC_U32_OFFSET|TC_U32_VAROFFSET)) {
off2 = n->sel.off + 3;
- if (n->sel.flags&TC_U32_VAROFFSET)
- off2 += ntohs(n->sel.offmask & *(__be16*)(ptr+n->sel.offoff)) >>n->sel.offshift;
+ if (n->sel.flags & TC_U32_VAROFFSET) {
+ __be16 *data, _data;
+
+ data = skb_header_pointer(skb,
+ off + n->sel.offoff,
+ 2, &_data);
+ if (!data)
+ goto out;
+ off2 += ntohs(n->sel.offmask & *data) >>
+ n->sel.offshift;
+ }
off2 &= ~3;
}
if (n->sel.flags&TC_U32_EAT) {
- ptr += off2;
+ off += off2;
off2 = 0;
}
- if (ptr < skb_tail_pointer(skb))
+ if (off < skb->len)
goto next_ht;
}
@@ -204,9 +226,10 @@ check_terminal:
if (sdepth--) {
n = stack[sdepth].knode;
ht = n->ht_up;
- ptr = stack[sdepth].ptr;
+ off = stack[sdepth].off;
goto check_terminal;
}
+out:
return -1;
deadloop: