linux-kernel - [PATCH] oprofilefs: Handle zero-length writes.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1313192539-19581-1-git-send-email-mikew@google.com>
Date:	Fri, 12 Aug 2011 16:42:19 -0700
From:	Mike Waychison <mikew@...gle.com>
To:	Robert Richter <robert.richter@....com>
Cc:	oprofile-list@...ts.sf.net, linux-kernel@...r.kernel.org,
	Mike Waychison <mikew@...gle.com>
Subject: [PATCH] oprofilefs: Handle zero-length writes.

Currently in oprofilefs, files that use ulong_fops mis-handle writes of
zero length.  A count of 0 causes oprofilefs_ulong_from_user to return
0 (success), which then leads to oprofile_set_ulong being called to
stuff "value" into file->private_data without it being initialized.

Fix this by moving the check for a zero-length write up into
ulong_write_file.

Signed-off-by: Mike Waychison <mikew@...gle.com>
---
 drivers/oprofile/oprofilefs.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/oprofile/oprofilefs.c b/drivers/oprofile/oprofilefs.c
index e9ff6f7..ee14e6e 100644
--- a/drivers/oprofile/oprofilefs.c
+++ b/drivers/oprofile/oprofilefs.c
@@ -65,9 +65,6 @@ int oprofilefs_ulong_from_user(unsigned long *val, char const __user *buf, size_
 	char tmpbuf[TMPBUFSIZE];
 	unsigned long flags;
 
-	if (!count)
-		return 0;
-
 	if (count > TMPBUFSIZE - 1)
 		return -EINVAL;
 
@@ -97,6 +94,8 @@ static ssize_t ulong_write_file(struct file *file, char const __user *buf, size_
 
 	if (*offset)
 		return -EINVAL;
+	if (count == 0)
+		return 0;
 
 	retval = oprofilefs_ulong_from_user(&value, buf, count);
 	if (retval)
-- 
1.7.3.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/