This is a note to let you know that I've just added the patch titled
netlink: don't compare the nul-termination in nla_strcmp
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
netlink-don-t-compare-the-nul-termination-in-nla_strcmp.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Mon Apr 14 15:32:12 PDT 2014
From: Pablo Neira <pablo@xxxxxxxxxxxxx>
Date: Tue, 1 Apr 2014 19:38:44 +0200
Subject: netlink: don't compare the nul-termination in nla_strcmp
From: Pablo Neira <pablo@xxxxxxxxxxxxx>
[ Upstream commit 8b7b932434f5eee495b91a2804f5b64ebb2bc835 ]
nla_strcmp compares the string length plus one, so it's implicitly
including the nul-termination in the comparison.
int nla_strcmp(const struct nlattr *nla, const char *str)
{
int len = strlen(str) + 1;
...
d = memcmp(nla_data(nla), str, len);
However, if NLA_STRING is used, userspace can send us a string without
the nul-termination. This is a problem since the string
comparison will not match as the last byte may be not the
nul-termination.
Fix this by skipping the comparison of the nul-termination if the
attribute data is nul-terminated. Suggested by Thomas Graf.
Cc: Florian Westphal <fw@xxxxxxxxx>
Cc: Thomas Graf <tgraf@xxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
lib/nlattr.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -299,9 +299,15 @@ int nla_memcmp(const struct nlattr *nla,
*/
int nla_strcmp(const struct nlattr *nla, const char *str)
{
- int len = strlen(str) + 1;
- int d = nla_len(nla) - len;
+ int len = strlen(str);
+ char *buf = nla_data(nla);
+ int attrlen = nla_len(nla);
+ int d;
+ if (attrlen > 0 && buf[attrlen - 1] == '\0')
+ attrlen--;
+
+ d = attrlen - len;
if (d == 0)
d = memcmp(nla_data(nla), str, len);
Patches currently in stable-queue which might be from pablo@xxxxxxxxxxxxx are
queue-3.4/netlink-don-t-compare-the-nul-termination-in-nla_strcmp.patch
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