[PATCH] sysctl: string length calculated is wrong if it contains negative numbers
authorBP, Praveen <praveenbp@ti.com>
Thu, 7 Dec 2006 04:39:09 +0000 (20:39 -0800)
committerLinus Torvalds <torvalds@woody.osdl.org>
Thu, 7 Dec 2006 16:39:42 +0000 (08:39 -0800)
commitbd9b0bac6f601655044fc35978e26231dffee03e
treeb6cc16149e406704e1e124aa159671beb63b7a56
parent36499dc2bc8025bc931a0fb22bbe0ac0e46ffb14
[PATCH] sysctl: string length calculated is wrong if it contains negative numbers

In the functions do_proc_dointvec() and do_proc_doulongvec_minmax(),
there seems to be a bug in string length calculation if string contains
negative integer.

The console log given below explains the bug. Setting negative values
may not be a right thing to do for "console log level" but then the test
(given below) can be used to demonstrate the bug in the code.

# echo "-1 -1 -1 -123456" > /proc/sys/kernel/printk
# cat /proc/sys/kernel/printk
-1      -1      -1      -1234
#
# echo "-1 -1 -1 123456" > /proc/sys/kernel/printk
# cat /proc/sys/kernel/printk
-1      -1      -1      1234
#

(akpm: the bug is that 123456 gets truncated)

It works as expected if string contains all +ve integers

# echo "1 2 3 4" > /proc/sys/kernel/printk
# cat /proc/sys/kernel/printk
1       2       3       4
#

The patch given below fixes the issue.

Signed-off-by: Praveen BP <praveenbp@ti.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
kernel/sysctl.c