zfs code - Apr 2010 - Possible use of uninitialized statbuf.

Hi.

I was looking at the code and it seems statbuf can be used without being
initialized in zpool_vdev.c:make_leaf_vdev().

We stat the given path only if it is not entire disk:

	if (arg[0] == ''/'') {
		/*
		 * Complete device or file path.  Exact type is
		 * determined by
		 * examining the file descriptor afterwards.
		 */
		wholedisk = is_whole_disk(arg);
		if (!wholedisk && (stat64(arg, &statbuf) != 0)) {
	[...]
	} else {
		/*
		 * This may be a short path for a device, or it could be
		 * total
		 * gibberish.  Check to see if it''s a known device in
		 * /dev/dsk/.  As part of this check, see if we''ve been
		 * given a
		 * an entire disk (minus the slice number).
		 */
		(void) snprintf(path, sizeof (path), "%s/%s", DISK_ROOT,
		    arg);
		wholedisk = is_whole_disk(path);
		if (!wholedisk && (stat64(path, &statbuf) != 0)) {
	[...]

Although later on we use statbuf in the following check:

	/*
	 * For a whole disk, defer getting its devid until after
	 * labeling it.
	 */
	if (S_ISBLK(statbuf.st_mode) && !wholedisk) {
	[...]

I think the best fix is to always stat the given file/device.
You can find the patch here:

	http://people.freebsd.org/~pjd/patches/zpool_vdev.c.patch

-- 
Pawel Jakub Dawidek                       http://www.wheelsystems.com
pjd at FreeBSD.org                           http://www.FreeBSD.org
FreeBSD committer                         Am I Evil? Yes, I Am!
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On 04/ 3/10 12:06 PM, Pawel Jakub Dawidek wrote:
> Hi.
>
> I was looking at the code and it seems statbuf can be used without being
> initialized in zpool_vdev.c:make_leaf_vdev().
>
Thanks,

I''ve opened the following bug to track this issue

6941196 possible use of unitialized statbuf

> We stat the given path only if it is not entire disk:
>
> 	if (arg[0] == ''/'') {
> 		/*
> 		 * Complete device or file path.  Exact type is
> 		 * determined by
> 		 * examining the file descriptor afterwards.
> 		 */
> 		wholedisk = is_whole_disk(arg);
> 		if (!wholedisk&&  (stat64(arg,&statbuf) != 0)) {
> 	[...]
> 	} else {
> 		/*
> 		 * This may be a short path for a device, or it could be
> 		 * total
> 		 * gibberish.  Check to see if it''s a known device in
> 		 * /dev/dsk/.  As part of this check, see if we''ve been
> 		 * given a
> 		 * an entire disk (minus the slice number).
> 		 */
> 		(void) snprintf(path, sizeof (path), "%s/%s", DISK_ROOT,
> 		    arg);
> 		wholedisk = is_whole_disk(path);
> 		if (!wholedisk&&  (stat64(path,&statbuf) != 0)) {
> 	[...]
>
> Although later on we use statbuf in the following check:
>
> 	/*
> 	 * For a whole disk, defer getting its devid until after
> 	 * labeling it.
> 	 */
> 	if (S_ISBLK(statbuf.st_mode)&&  !wholedisk) {
> 	[...]
>
> I think the best fix is to always stat the given file/device.
> You can find the patch here:
>
> 	http://people.freebsd.org/~pjd/patches/zpool_vdev.c.patch
>
>
>
>
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