[patch 6/9] param_sysfs_builtin memchr argument fix

From: Greg KH
Date: Fri Nov 02 2007 - 14:01:25 EST


2.6.22-stable review patch. If anyone has any objections, please let us
know.

------------------
From: Dave Young <hidave.darkstar@xxxxxxxxx>

patch faf8c714f4508207a9c81cc94dafc76ed6680b44 in mainline.

If memchr argument is longer than strlen(kp->name), there will be some
weird result.

It will casuse duplicate filenames in sysfs for the "nousb". kernel
warning messages are as bellow:

sysfs: duplicate filename 'usbcore' can not be created
WARNING: at fs/sysfs/dir.c:416 sysfs_add_one()
[<c01c4750>] sysfs_add_one+0xa0/0xe0
[<c01c4ab8>] create_dir+0x48/0xb0
[<c01c4b69>] sysfs_create_dir+0x29/0x50
[<c024e0fb>] create_dir+0x1b/0x50
[<c024e3b6>] kobject_add+0x46/0x150
[<c024e2da>] kobject_init+0x3a/0x80
[<c053b880>] kernel_param_sysfs_setup+0x50/0xb0
[<c053b9ce>] param_sysfs_builtin+0xee/0x130
[<c053ba33>] param_sysfs_init+0x23/0x60
[<c024d062>] __next_cpu+0x12/0x20
[<c052aa30>] kernel_init+0x0/0xb0
[<c052aa30>] kernel_init+0x0/0xb0
[<c052a856>] do_initcalls+0x46/0x1e0
[<c01bdb12>] create_proc_entry+0x52/0x90
[<c0158d4c>] register_irq_proc+0x9c/0xc0
[<c01bda94>] proc_mkdir_mode+0x34/0x50
[<c052aa30>] kernel_init+0x0/0xb0
[<c052aa92>] kernel_init+0x62/0xb0
[<c0104f83>] kernel_thread_helper+0x7/0x14
=======================
kobject_add failed for usbcore with -EEXIST, don't try to register things with the same name in the same directory.
[<c024e466>] kobject_add+0xf6/0x150
[<c053b880>] kernel_param_sysfs_setup+0x50/0xb0
[<c053b9ce>] param_sysfs_builtin+0xee/0x130
[<c053ba33>] param_sysfs_init+0x23/0x60
[<c024d062>] __next_cpu+0x12/0x20
[<c052aa30>] kernel_init+0x0/0xb0
[<c052aa30>] kernel_init+0x0/0xb0
[<c052a856>] do_initcalls+0x46/0x1e0
[<c01bdb12>] create_proc_entry+0x52/0x90
[<c0158d4c>] register_irq_proc+0x9c/0xc0
[<c01bda94>] proc_mkdir_mode+0x34/0x50
[<c052aa30>] kernel_init+0x0/0xb0
[<c052aa92>] kernel_init+0x62/0xb0
[<c0104f83>] kernel_thread_helper+0x7/0x14
=======================
Module 'usbcore' failed to be added to sysfs, error number -17
The system will be unstable now.

Signed-off-by: Dave Young <hidave.darkstar@xxxxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Chuck Ebbert <cebbert@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
kernel/params.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

--- a/kernel/params.c
+++ b/kernel/params.c
@@ -591,11 +591,17 @@ static void __init param_sysfs_builtin(v

for (i=0; i < __stop___param - __start___param; i++) {
char *dot;
+ size_t kplen;

kp = &__start___param[i];
+ kplen = strlen(kp->name);

/* We do not handle args without periods. */
- dot = memchr(kp->name, '.', MAX_KBUILD_MODNAME);
+ if (kplen > MAX_KBUILD_MODNAME) {
+ DEBUGP("kernel parameter name is too long: %s\n", kp->name);
+ continue;
+ }
+ dot = memchr(kp->name, '.', kplen);
if (!dot) {
DEBUGP("couldn't find period in %s\n", kp->name);
continue;

--
-
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