Patchwork [28/88] sysctl: fix null checking in bin_dn_node_address()

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Submitter Luis Henriques
Date March 14, 2013, 10:35 a.m.
Message ID <1363257381-15900-29-git-send-email-luis.henriques@canonical.com>
Download mbox | patch
Permalink /patch/227587/
State New
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Luis Henriques - March 14, 2013, 10:35 a.m.
3.5.7.8 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Xi Wang <xi.wang@gmail.com>

commit df1778be1a33edffa51d094eeda87c858ded6560 upstream.

The null check of `strchr() + 1' is broken, which is always non-null,
leading to OOB read.  Instead, check the result of strchr().

Signed-off-by: Xi Wang <xi.wang@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 kernel/sysctl_binary.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Patch

diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
index a650694..9f9aa32 100644
--- a/kernel/sysctl_binary.c
+++ b/kernel/sysctl_binary.c
@@ -1194,9 +1194,10 @@  static ssize_t bin_dn_node_address(struct file *file,
 
 		/* Convert the decnet address to binary */
 		result = -EIO;
-		nodep = strchr(buf, '.') + 1;
+		nodep = strchr(buf, '.');
 		if (!nodep)
 			goto out;
+		++nodep;
 
 		area = simple_strtoul(buf, NULL, 10);
 		node = simple_strtoul(nodep, NULL, 10);