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[3.8.y.z,extended,stable] Patch "uml: check length in exitcode_proc_write()" has been added to staging queue

Message ID 1383876541-613-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa Nov. 8, 2013, 2:09 a.m. UTC
This is a note to let you know that I have just added a patch titled

    uml: check length in exitcode_proc_write()

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.13.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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From 364d11a0f36ed035a0adf09699da8d8b710a553c Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Tue, 29 Oct 2013 22:06:04 +0300
Subject: uml: check length in exitcode_proc_write()

commit 201f99f170df14ba52ea4c52847779042b7a623b upstream.

We don't cap the size of buffer from the user so we could write past the
end of the array here.  Only root can write to this file.

Reported-by: Nico Golde <nico@ngolde.de>
Reported-by: Fabian Yamaguchi <fabs@goesec.de>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 arch/um/kernel/exitcode.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--
1.8.1.2
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Patch

diff --git a/arch/um/kernel/exitcode.c b/arch/um/kernel/exitcode.c
index 829df49..41ebbfe 100644
--- a/arch/um/kernel/exitcode.c
+++ b/arch/um/kernel/exitcode.c
@@ -40,9 +40,11 @@  static ssize_t exitcode_proc_write(struct file *file,
 		const char __user *buffer, size_t count, loff_t *pos)
 {
 	char *end, buf[sizeof("nnnnn\0")];
+	size_t size;
 	int tmp;

-	if (copy_from_user(buf, buffer, count))
+	size = min(count, sizeof(buf));
+	if (copy_from_user(buf, buffer, size))
 		return -EFAULT;

 	tmp = simple_strtol(buf, &end, 0);