diff options
author | David S. Miller <davem@sunset.davemloft.net> | 2006-02-13 16:06:10 -0800 |
---|---|---|
committer | David S. Miller <davem@sunset.davemloft.net> | 2006-02-13 16:06:10 -0800 |
commit | b4d9eda028e8becbb5057b554e63eea12e496a88 (patch) | |
tree | f3dfa4aa380fe89a4aeff049c2f5b13b72404a1b | |
parent | 00de651d14baabc5c1d2f32c49d9a984d8891c8e (diff) | |
download | op-kernel-dev-b4d9eda028e8becbb5057b554e63eea12e496a88.zip op-kernel-dev-b4d9eda028e8becbb5057b554e63eea12e496a88.tar.gz |
[NET]: Revert skb_copy_datagram_iovec() recursion elimination.
Revert the following changeset:
bc8dfcb93970ad7139c976356bfc99d7e251deaf
Recursive SKB frag lists are really possible and disallowing
them breaks things.
Noticed by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r-- | net/core/datagram.c | 81 |
1 files changed, 53 insertions, 28 deletions
diff --git a/net/core/datagram.c b/net/core/datagram.c index f8d322e..b8ce6bf 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -247,49 +247,74 @@ EXPORT_SYMBOL(skb_kill_datagram); int skb_copy_datagram_iovec(const struct sk_buff *skb, int offset, struct iovec *to, int len) { - int i, err, fraglen, end = 0; - struct sk_buff *next = skb_shinfo(skb)->frag_list; + int start = skb_headlen(skb); + int i, copy = start - offset; - if (!len) - return 0; + /* Copy header. */ + if (copy > 0) { + if (copy > len) + copy = len; + if (memcpy_toiovec(to, skb->data + offset, copy)) + goto fault; + if ((len -= copy) == 0) + return 0; + offset += copy; + } -next_skb: - fraglen = skb_headlen(skb); - i = -1; + /* Copy paged appendix. Hmm... why does this look so complicated? */ + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + int end; - while (1) { - int start = end; + BUG_TRAP(start <= offset + len); - if ((end += fraglen) > offset) { - int copy = end - offset, o = offset - start; + end = start + skb_shinfo(skb)->frags[i].size; + if ((copy = end - offset) > 0) { + int err; + u8 *vaddr; + skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + struct page *page = frag->page; if (copy > len) copy = len; - if (i == -1) - err = memcpy_toiovec(to, skb->data + o, copy); - else { - skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; - struct page *page = frag->page; - void *p = kmap(page) + frag->page_offset + o; - err = memcpy_toiovec(to, p, copy); - kunmap(page); - } + vaddr = kmap(page); + err = memcpy_toiovec(to, vaddr + frag->page_offset + + offset - start, copy); + kunmap(page); if (err) goto fault; if (!(len -= copy)) return 0; offset += copy; } - if (++i >= skb_shinfo(skb)->nr_frags) - break; - fraglen = skb_shinfo(skb)->frags[i].size; + start = end; } - if (next) { - skb = next; - BUG_ON(skb_shinfo(skb)->frag_list); - next = skb->next; - goto next_skb; + + if (skb_shinfo(skb)->frag_list) { + struct sk_buff *list = skb_shinfo(skb)->frag_list; + + for (; list; list = list->next) { + int end; + + BUG_TRAP(start <= offset + len); + + end = start + list->len; + if ((copy = end - offset) > 0) { + if (copy > len) + copy = len; + if (skb_copy_datagram_iovec(list, + offset - start, + to, copy)) + goto fault; + if ((len -= copy) == 0) + return 0; + offset += copy; + } + start = end; + } } + if (!len) + return 0; + fault: return -EFAULT; } |