From 3278682123811dd8ef07de5eb701fc4548fcebf2 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 17 Feb 2017 20:16:34 -0500 Subject: make skb_copy_datagram_msg() et.al. preserve ->msg_iter on error Fixes the mess observed in e.g. rsync over a noisy link we'd been seeing since last Summer. What happens is that we copy part of a datagram before noticing a checksum mismatch. Datagram will be resent, all right, but we want the next try go into the same place, not after it... All this family of primitives (copy/checksum and copy a datagram into destination) is "all or nothing" sort of interface - either we get 0 (meaning that copy had been successful) or we get an error (and no way to tell how much had been copied before we ran into whatever error it had been). Make all of them leave iterator unadvanced in case of errors - all callers must be able to cope with that (an error might've been caught before the iterator had been advanced), it costs very little to arrange, it's safer for callers and actually fixes at least one bug in said callers. Cc: stable@vger.kernel.org Signed-off-by: Al Viro --- net/core/datagram.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) (limited to 'net/core') diff --git a/net/core/datagram.c b/net/core/datagram.c index ea633342ab0d..f4947e737f34 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -398,7 +398,7 @@ int skb_copy_datagram_iter(const struct sk_buff *skb, int offset, struct iov_iter *to, int len) { int start = skb_headlen(skb); - int i, copy = start - offset; + int i, copy = start - offset, start_off = offset, n; struct sk_buff *frag_iter; trace_skb_copy_datagram_iovec(skb, len); @@ -407,11 +407,12 @@ int skb_copy_datagram_iter(const struct sk_buff *skb, int offset, if (copy > 0) { if (copy > len) copy = len; - if (copy_to_iter(skb->data + offset, copy, to) != copy) + n = copy_to_iter(skb->data + offset, copy, to); + offset += n; + if (n != copy) goto short_copy; if ((len -= copy) == 0) return 0; - offset += copy; } /* Copy paged appendix. Hmm... why does this look so complicated? */ @@ -425,13 +426,14 @@ int skb_copy_datagram_iter(const struct sk_buff *skb, int offset, if ((copy = end - offset) > 0) { if (copy > len) copy = len; - if (copy_page_to_iter(skb_frag_page(frag), + n = copy_page_to_iter(skb_frag_page(frag), frag->page_offset + offset - - start, copy, to) != copy) + start, copy, to); + offset += n; + if (n != copy) goto short_copy; if (!(len -= copy)) return 0; - offset += copy; } start = end; } @@ -463,6 +465,7 @@ int skb_copy_datagram_iter(const struct sk_buff *skb, int offset, */ fault: + iov_iter_revert(to, offset - start_off); return -EFAULT; short_copy: @@ -613,7 +616,7 @@ static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset, __wsum *csump) { int start = skb_headlen(skb); - int i, copy = start - offset; + int i, copy = start - offset, start_off = offset; struct sk_buff *frag_iter; int pos = 0; int n; @@ -623,11 +626,11 @@ static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset, if (copy > len) copy = len; n = csum_and_copy_to_iter(skb->data + offset, copy, csump, to); + offset += n; if (n != copy) goto fault; if ((len -= copy) == 0) return 0; - offset += copy; pos = copy; } @@ -649,12 +652,12 @@ static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset, offset - start, copy, &csum2, to); kunmap(page); + offset += n; if (n != copy) goto fault; *csump = csum_block_add(*csump, csum2, pos); if (!(len -= copy)) return 0; - offset += copy; pos += copy; } start = end; @@ -687,6 +690,7 @@ static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset, return 0; fault: + iov_iter_revert(to, offset - start_off); return -EFAULT; } @@ -771,6 +775,7 @@ int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, } return 0; csum_error: + iov_iter_revert(&msg->msg_iter, chunk); return -EINVAL; fault: return -EFAULT; -- cgit v1.2.3 From df7dd8fc965c665e83b71a649378cdf200ff36df Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Wed, 12 Apr 2017 09:32:07 +0200 Subject: net: xdp: don't export dev_change_xdp_fd() Since dev_change_xdp_fd() is only used in rtnetlink, which must be built-in, there's no reason to export dev_change_xdp_fd(). Signed-off-by: Johannes Berg Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- net/core/dev.c | 1 - 1 file changed, 1 deletion(-) (limited to 'net/core') diff --git a/net/core/dev.c b/net/core/dev.c index 7869ae3837ca..533a6d6f6092 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6757,7 +6757,6 @@ int dev_change_xdp_fd(struct net_device *dev, int fd, u32 flags) return err; } -EXPORT_SYMBOL(dev_change_xdp_fd); /** * dev_new_index - allocate an ifindex -- cgit v1.2.3