Re: [PATCH 1/1 V2] ipv4: off-by-one in continuation handling in /proc/net/route
From: Andy Whitcroft
Date: Thu, 13 Aug 2015 20:49:01 +0100
> When generating /proc/net/route we emit a header followed by a line for
> each route. When a short read is performed we will restart this process
> based on the open file descriptor. When calculating the start point we
> fail to take into account that the 0th entry is the header. This leads
> us to skip the first entry when doing a continuation read.
>
> This can be easily seen with the comparison below:
>
> while read l; do echo "$l"; done A
> cat /proc/net/route >B
> diff -bu A B | grep '^[+-]'
>
> On my example machine I have approximatly 10KB of route output. There we
> see the very first non-title element is lost in the while read case,
> and an entry around the 8K mark in the cat case:
>
> +wlan0 02021EAC 0003 0 0 400 0 0 0
> -tun1 00C0AC0A 0001 0 0 950 00C0 0 0 0
>
> Fix up the off-by-one when reaquiring position on continuation.
>
> Fixes: 8be33e955cb9 ("fib_trie: Fib walk rcu should take a tnode and key
> instead of a trie and a leaf")
> BugLink: http://bugs.launchpad.net/bugs/1483440
> Acked-by: Alexander Duyck
> Signed-off-by: Andy Whitcroft
Applied and queued up for -stable, thanks.
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[PATCH 1/1 V2] ipv4: off-by-one in continuation handling in /proc/net/route
When generating /proc/net/route we emit a header followed by a line for
each route. When a short read is performed we will restart this process
based on the open file descriptor. When calculating the start point we
fail to take into account that the 0th entry is the header. This leads
us to skip the first entry when doing a continuation read.
This can be easily seen with the comparison below:
while read l; do echo "$l"; done A
cat /proc/net/route >B
diff -bu A B | grep '^[+-]'
On my example machine I have approximatly 10KB of route output. There we
see the very first non-title element is lost in the while read case,
and an entry around the 8K mark in the cat case:
+wlan0 02021EAC 0003 0 0 400 0 0 0
-tun1 00C0AC0A 0001 0 0 950 00C0 0 0 0
Fix up the off-by-one when reaquiring position on continuation.
Fixes: 8be33e955cb9 ("fib_trie: Fib walk rcu should take a tnode and key
instead of a trie and a leaf")
BugLink: http://bugs.launchpad.net/bugs/1483440
Acked-by: Alexander Duyck
Signed-off-by: Andy Whitcroft
---
net/ipv4/fib_trie.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
V2 incorporates the updated Fixes: line as suggested by Eric,
and incorporates Alexander's Ack.
This is for applicable to net and to suitable for stable trees
v4.1 and up.
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 37c4bb8..b0c6258 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -2465,7 +2465,7 @@ static struct key_vector *fib_route_get_idx(struct
fib_route_iter *iter,
key = l->key + 1;
iter->pos++;
- if (pos-- <= 0)
+ if (--pos <= 0)
break;
l = NULL;
--
2.5.0
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[PATCH 1/1 V2] ipv4: off-by-one in continuation handling in /proc/net/route
When generating /proc/net/route we emit a header followed by a line for each route. When a short read is performed we will restart this process based on the open file descriptor. When calculating the start point we fail to take into account that the 0th entry is the header. This leads us to skip the first entry when doing a continuation read. This can be easily seen with the comparison below: while read l; do echo $l; done /proc/net/route A cat /proc/net/route B diff -bu A B | grep '^[+-]' On my example machine I have approximatly 10KB of route output. There we see the very first non-title element is lost in the while read case, and an entry around the 8K mark in the cat case: +wlan0 02021EAC 0003 0 0 400 0 0 0 -tun1 00C0AC0A 0001 0 0 950 00C0 0 0 0 Fix up the off-by-one when reaquiring position on continuation. Fixes: 8be33e955cb9 (fib_trie: Fib walk rcu should take a tnode and key instead of a trie and a leaf) BugLink: http://bugs.launchpad.net/bugs/1483440 Acked-by: Alexander Duyck alexander.h.du...@redhat.com Signed-off-by: Andy Whitcroft a...@canonical.com --- net/ipv4/fib_trie.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) V2 incorporates the updated Fixes: line as suggested by Eric, and incorporates Alexander's Ack. This is for applicable to net and to suitable for stable trees v4.1 and up. diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c index 37c4bb8..b0c6258 100644 --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -2465,7 +2465,7 @@ static struct key_vector *fib_route_get_idx(struct fib_route_iter *iter, key = l-key + 1; iter-pos++; - if (pos-- = 0) + if (--pos = 0) break; l = NULL; -- 2.5.0 -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 1/1 V2] ipv4: off-by-one in continuation handling in /proc/net/route
From: Andy Whitcroft a...@canonical.com Date: Thu, 13 Aug 2015 20:49:01 +0100 When generating /proc/net/route we emit a header followed by a line for each route. When a short read is performed we will restart this process based on the open file descriptor. When calculating the start point we fail to take into account that the 0th entry is the header. This leads us to skip the first entry when doing a continuation read. This can be easily seen with the comparison below: while read l; do echo $l; done /proc/net/route A cat /proc/net/route B diff -bu A B | grep '^[+-]' On my example machine I have approximatly 10KB of route output. There we see the very first non-title element is lost in the while read case, and an entry around the 8K mark in the cat case: +wlan0 02021EAC 0003 0 0 400 0 0 0 -tun1 00C0AC0A 0001 0 0 950 00C0 0 0 0 Fix up the off-by-one when reaquiring position on continuation. Fixes: 8be33e955cb9 (fib_trie: Fib walk rcu should take a tnode and key instead of a trie and a leaf) BugLink: http://bugs.launchpad.net/bugs/1483440 Acked-by: Alexander Duyck alexander.h.du...@redhat.com Signed-off-by: Andy Whitcroft a...@canonical.com Applied and queued up for -stable, thanks. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
