diff options
| author | Changli Gao <xiaosuo@gmail.com> | 2010-06-02 07:32:42 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-06-02 07:32:42 -0700 |
| commit | fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d (patch) | |
| tree | a82f11f0ea06fd465393314d0f37772f715c6caf /net/sched/cls_u32.c | |
| parent | edafe502404f3669d364b6e96d79b54067b634b4 (diff) | |
| download | linux-fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d.tar.gz | |
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/sched/cls_u32.c')
| -rw-r--r-- | net/sched/cls_u32.c | 49 |
1 files changed, 36 insertions, 13 deletions
diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c index 96275422c619..4f522143811e 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: |