[PATCH v2] isdnloop: fix and simplify isdnloop_init()

On Thu, Aug 02, 2012 at 04:21:56PM -0700, David Miller wrote:

From: Fengguang Wu <redacted>
Date: Thu, 2 Aug 2012 19:05:43 +0800

quoted

Fix a buffer overflow bug by removing the revision transform code.

[   22.016214] isdnloop-ISDN-driver Rev 1.11.6.7 
[   22.097508] isdnloop: (loop0) virtual card added
[   22.174400] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffff83244972
[   22.174400] 
[   22.436157] Pid: 1, comm: swapper Not tainted 3.5.0-bisect-00018-gfa8bbb1-dirty #129
[   22.624071] Call Trace:
[   22.720558]  [<ffffffff832448c3>] ? CallcNew+0x56/0x56
[   22.815248]  [<ffffffff8222b623>] panic+0x110/0x329
[   22.914330]  [<ffffffff83244972>] ? isdnloop_init+0xaf/0xb1
[   23.014800]  [<ffffffff832448c3>] ? CallcNew+0x56/0x56
[   23.090763]  [<ffffffff8108e24b>] __stack_chk_fail+0x2b/0x30
[   23.185748]  [<ffffffff83244972>] isdnloop_init+0xaf/0xb1

Signed-off-by: Fengguang Wu <redacted>

The reason the "$Revision ..." prefix is there is so that automated
version control tools will change the string automatically when code
is committed in CVS.

In the GIT era this revision style is obsolete.

Therefore you might as well just delete this crap altogether.

OK. The below updated version will simply print the hard coded
revision number as it's unlikely to change any more.

Thanks,
Fengguang
---
isdnloop: fix and simplify isdnloop_init

Fix a buffer overflow bug by hard coding the revision number.

[   22.016214] isdnloop-ISDN-driver Rev 1.11.6.7 
[   22.097508] isdnloop: (loop0) virtual card added
[   22.174400] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffff83244972
[   22.174400] 
[   22.436157] Pid: 1, comm: swapper Not tainted 3.5.0-bisect-00018-gfa8bbb1-dirty #129
[   22.624071] Call Trace:
[   22.720558]  [<ffffffff832448c3>] ? CallcNew+0x56/0x56
[   22.815248]  [<ffffffff8222b623>] panic+0x110/0x329
[   22.914330]  [<ffffffff83244972>] ? isdnloop_init+0xaf/0xb1
[   23.014800]  [<ffffffff832448c3>] ? CallcNew+0x56/0x56
[   23.090763]  [<ffffffff8108e24b>] __stack_chk_fail+0x2b/0x30
[   23.185748]  [<ffffffff83244972>] isdnloop_init+0xaf/0xb1

Signed-off-by: Fengguang Wu <redacted>
---
 drivers/isdn/isdnloop/isdnloop.c |   12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

--- linux.orig/drivers/isdn/isdnloop/isdnloop.c	2012-08-03 15:24:49.047544323 +0800
+++ linux/drivers/isdn/isdnloop/isdnloop.c	2012-08-03 15:27:39.503548375 +0800

@@ -16,7 +16,6 @@
 #include <linux/sched.h>
 #include "isdnloop.h"
 
-static char *revision = "$Revision: 1.11.6.7 $";
 static char *isdnloop_id = "loop0";
 
 MODULE_DESCRIPTION("ISDN4Linux: Pseudo Driver that simulates an ISDN card");

@@ -1494,16 +1493,7 @@ isdnloop_addcard(char *id1)
 static int __init
 isdnloop_init(void)
 {
-	char *p;
-	char rev[10];
-
-	if ((p = strchr(revision, ':'))) {
-		strcpy(rev, p + 1);
-		p = strchr(rev, '$');
-		*p = 0;
-	} else
-		strcpy(rev, " ??? ");
-	printk(KERN_NOTICE "isdnloop-ISDN-driver Rev%s\n", rev);
+	printk(KERN_NOTICE "isdnloop-ISDN-driver Rev 1.11.6.7\n");
 
 	if (isdnloop_id)
 		return (isdnloop_addcard(isdnloop_id));