[v3] jfs: validate max amount of blocks before allocation.

[PATCH v3] jfs: validate max amount of blocks before allocation.

Posted by Aleksei Filippov 2 years, 6 months ago

From: Alexei Filippov <halip0503@gmail.com>

The lack of checking bmp->db_max_freebud in extBalloc() can lead to
shift out of bounds, so this patch prevents undefined behavior, because
bmp->db_max_freebud == -1 only if there is no free space.

Signed-off-by: Aleksei Filippov <halip0503@gmail.com>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-and-tested-by: syzbot+5f088f29593e6b4c8db8@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?id=01abadbd6ae6a08b1f1987aa61554c6b3ac19ff2
---
 fs/jfs/jfs_extent.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/jfs/jfs_extent.c b/fs/jfs/jfs_extent.c
index ae99a7e232ee..a82751e6c47f 100644
--- a/fs/jfs/jfs_extent.c
+++ b/fs/jfs/jfs_extent.c
@@ -311,6 +311,11 @@ extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
 	 * blocks in the map. in that case, we'll start off with the
 	 * maximum free.
 	 */
+
+	/* give up if no space left */
+	if (bmp->db_maxfreebud == -1)
+		return -ENOSPC;
+
 	max = (s64) 1 << bmp->db_maxfreebud;
 	if (*nblocks >= max && *nblocks > nbperpage)
 		nb = nblks = (max > nbperpage) ? max : nbperpage;
-- 
2.25.1

Fix commit message.

Re: [PATCH v3] jfs: validate max amount of blocks before allocation.

Posted by Greg KH 2 years, 6 months ago

On Sun, Jul 23, 2023 at 04:29:59PM +0300, Aleksei Filippov wrote:
> From: Alexei Filippov <halip0503@gmail.com>
> 
> The lack of checking bmp->db_max_freebud in extBalloc() can lead to
> shift out of bounds, so this patch prevents undefined behavior, because
> bmp->db_max_freebud == -1 only if there is no free space.
> 
> Signed-off-by: Aleksei Filippov <halip0503@gmail.com>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Reported-and-tested-by: syzbot+5f088f29593e6b4c8db8@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?id=01abadbd6ae6a08b1f1987aa61554c6b3ac19ff2
> ---
>  fs/jfs/jfs_extent.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/fs/jfs/jfs_extent.c b/fs/jfs/jfs_extent.c
> index ae99a7e232ee..a82751e6c47f 100644
> --- a/fs/jfs/jfs_extent.c
> +++ b/fs/jfs/jfs_extent.c
> @@ -311,6 +311,11 @@ extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
>  	 * blocks in the map. in that case, we'll start off with the
>  	 * maximum free.
>  	 */
> +
> +	/* give up if no space left */
> +	if (bmp->db_maxfreebud == -1)
> +		return -ENOSPC;
> +
>  	max = (s64) 1 << bmp->db_maxfreebud;
>  	if (*nblocks >= max && *nblocks > nbperpage)
>  		nb = nblks = (max > nbperpage) ? max : nbperpage;
> -- 
> 2.25.1
> 
> Fix commit message.

The --- information for the version goes below the first --- line, not
the last.  Look at the examples on the mailing lists for the proper
format.

thanks,

greg k-h

[PATCH v4] jfs: validate max amount of blocks before allocation.

Posted by Aleksei Filippov 2 years, 6 months ago

From: Alexei Filippov <halip0503@gmail.com>

The lack of checking bmp->db_max_freebud in extBalloc() can lead to
shift out of bounds, so this patch prevents undefined behavior, because
bmp->db_max_freebud == -1 only if there is no free space.

Signed-off-by: Aleksei Filippov <halip0503@gmail.com>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-and-tested-by: syzbot+5f088f29593e6b4c8db8@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?id=01abadbd6ae6a08b1f1987aa61554c6b3ac19ff2
---
Changes:
Fix commit message.
 fs/jfs/jfs_extent.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/jfs/jfs_extent.c b/fs/jfs/jfs_extent.c
index ae99a7e232ee..a82751e6c47f 100644
--- a/fs/jfs/jfs_extent.c
+++ b/fs/jfs/jfs_extent.c
@@ -311,6 +311,11 @@ extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
 	 * blocks in the map. in that case, we'll start off with the
 	 * maximum free.
 	 */
+
+	/* give up if no space left */
+	if (bmp->db_maxfreebud == -1)
+		return -ENOSPC;
+
 	max = (s64) 1 << bmp->db_maxfreebud;
 	if (*nblocks >= max && *nblocks > nbperpage)
 		nb = nblks = (max > nbperpage) ? max : nbperpage;
-- 
2.25.1

Re: [PATCH v4] jfs: validate max amount of blocks before allocation.

Posted by Greg KH 2 years, 6 months ago

On Sun, Jul 23, 2023 at 04:58:22PM +0300, Aleksei Filippov wrote:
> From: Alexei Filippov <halip0503@gmail.com>
> 
> The lack of checking bmp->db_max_freebud in extBalloc() can lead to
> shift out of bounds, so this patch prevents undefined behavior, because
> bmp->db_max_freebud == -1 only if there is no free space.
> 
> Signed-off-by: Aleksei Filippov <halip0503@gmail.com>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Reported-and-tested-by: syzbot+5f088f29593e6b4c8db8@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?id=01abadbd6ae6a08b1f1987aa61554c6b3ac19ff2
> ---
> Changes:
> Fix commit message.
>  fs/jfs/jfs_extent.c | 5 +++++
>  1 file changed, 5 insertions(+)

{sigh}

Please, take some time, read the documentation for how to do this
correctly.  Wait a day, and then submit it again, properly.

Also, do you have a jfs system?  Isn't this filesystem obsolete?

thanks,

greg k-h

[PATCH v5] jfs: validate max amount of blocks before allocation.

Posted by Aleksei Filippov 2 years, 5 months ago

From: Alexei Filippov <halip0503@gmail.com>

The lack of checking bmp->db_max_freebud in extBalloc() can lead to
shift out of bounds, so this patch prevents undefined behavior, because
bmp->db_max_freebud == -1 only if there is no free space.

Signed-off-by: Aleksei Filippov <halip0503@gmail.com>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-and-tested-by: syzbot+5f088f29593e6b4c8db8@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?id=01abadbd6ae6a08b1f1987aa61554c6b3ac19ff2
---

Changes since v1:
	-Commit message fix. Add Fixes line.
Changes since v2-v4:
	-Commit message fixes.
 fs/jfs/jfs_extent.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/jfs/jfs_extent.c b/fs/jfs/jfs_extent.c
index ae99a7e232ee..a82751e6c47f 100644
--- a/fs/jfs/jfs_extent.c
+++ b/fs/jfs/jfs_extent.c
@@ -311,6 +311,11 @@ extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
 	 * blocks in the map. in that case, we'll start off with the
 	 * maximum free.
 	 */
+
+	/* give up if no space left */
+	if (bmp->db_maxfreebud == -1)
+		return -ENOSPC;
+
 	max = (s64) 1 << bmp->db_maxfreebud;
 	if (*nblocks >= max && *nblocks > nbperpage)
 		nb = nblks = (max > nbperpage) ? max : nbperpage;
-- 
2.25.1

Re: [PATCH v5] jfs: validate max amount of blocks before allocation.

Posted by Dave Kleikamp 2 years, 5 months ago

On 8/19/23 12:32PM, Aleksei Filippov wrote:
> From: Alexei Filippov <halip0503@gmail.com>
> 
> The lack of checking bmp->db_max_freebud in extBalloc() can lead to
> shift out of bounds, so this patch prevents undefined behavior, because
> bmp->db_max_freebud == -1 only if there is no free space.

Thanks. Applied.

> 
> Signed-off-by: Aleksei Filippov <halip0503@gmail.com>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Reported-and-tested-by: syzbot+5f088f29593e6b4c8db8@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?id=01abadbd6ae6a08b1f1987aa61554c6b3ac19ff2
> ---
> 
> Changes since v1:
> 	-Commit message fix. Add Fixes line.
> Changes since v2-v4:
> 	-Commit message fixes.
>   fs/jfs/jfs_extent.c | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/fs/jfs/jfs_extent.c b/fs/jfs/jfs_extent.c
> index ae99a7e232ee..a82751e6c47f 100644
> --- a/fs/jfs/jfs_extent.c
> +++ b/fs/jfs/jfs_extent.c
> @@ -311,6 +311,11 @@ extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
>   	 * blocks in the map. in that case, we'll start off with the
>   	 * maximum free.
>   	 */
> +
> +	/* give up if no space left */
> +	if (bmp->db_maxfreebud == -1)
> +		return -ENOSPC;
> +
>   	max = (s64) 1 << bmp->db_maxfreebud;
>   	if (*nblocks >= max && *nblocks > nbperpage)
>   		nb = nblks = (max > nbperpage) ? max : nbperpage;