47 lines
1.7 KiB
Diff
47 lines
1.7 KiB
Diff
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From 25b97c016b26039982daaa2c11d83979f93b71ab Mon Sep 17 00:00:00 2001
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From: Andy Whitcroft <apw@canonical.com>
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Date: Thu, 13 Aug 2015 20:49:01 +0100
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Subject: [PATCH] ipv4: off-by-one in continuation handling in /proc/net/route
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When generating /proc/net/route we emit a header followed by a line for
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each route. When a short read is performed we will restart this process
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based on the open file descriptor. When calculating the start point we
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fail to take into account that the 0th entry is the header. This leads
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us to skip the first entry when doing a continuation read.
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This can be easily seen with the comparison below:
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while read l; do echo "$l"; done </proc/net/route >A
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cat /proc/net/route >B
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diff -bu A B | grep '^[+-]'
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On my example machine I have approximatly 10KB of route output. There we
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see the very first non-title element is lost in the while read case,
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and an entry around the 8K mark in the cat case:
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+wlan0 00000000 02021EAC 0003 0 0 400 00000000 0 0 0
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-tun1 00C0AC0A 00000000 0001 0 0 950 00C0FFFF 0 0 0
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Fix up the off-by-one when reaquiring position on continuation.
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Fixes: 8be33e955cb9 ("fib_trie: Fib walk rcu should take a tnode and key instead of a trie and a leaf")
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BugLink: http://bugs.launchpad.net/bugs/1483440
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Acked-by: Alexander Duyck <alexander.h.duyck@redhat.com>
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Signed-off-by: Andy Whitcroft <apw@canonical.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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net/ipv4/fib_trie.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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--- a/net/ipv4/fib_trie.c
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+++ b/net/ipv4/fib_trie.c
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@@ -2457,7 +2457,7 @@ static struct key_vector *fib_route_get_
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key = l->key + 1;
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iter->pos++;
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- if (pos-- <= 0)
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+ if (--pos <= 0)
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break;
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l = NULL;
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