md/bitmap: return an error when bitmap superblock is corrupt.

commit b97e92574c0bf335db1cd2ec491d8ff5cd5d0b49 upstream
Use separate bitmaps for each nodes in the cluster

bitmap_read_sb() validates the bitmap superblock that it reads in. If it finds an inconsistency like a bad magic number or out-of-range version number, it prints an error and returns, but it incorrectly returns zero, so the array is still assembled with the (invalid) bitmap.

This means it could try to use a bitmap with a new version number which it therefore does not understand.

This bug was introduced in 3.5 and fix as part of a larger patch in 4.1. So the patch is suitable for any -stable kernel in that range.

index 3a5767968ba0..894fd58f75f1 100644
@@ -577,6 +577,8 @@ static int bitmap_read_sb(struct bitmap *bitmap)
 	if (err)
 		return err;
 
+	err = -EINVAL;
+
 	sb = kmap_atomic(sb_page);
 
 	chunksize = le32_to_cpu(sb->chunksize);

b97e92574c0 is in 4.1, so do you mean (v3.5..v4.0) here?

thanks,

greg k-h

Yes, I did. Thanks!

v3.5..v4.0.

NeilBrown

This is a note to let you know that I've just added the patch titled

md/bitmap: return an error when bitmap superblock is corrupt.

to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
md-bitmap-return-an-error-when-bitmap-superblock-is-corrupt.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From [email protected] Fri Aug 14 10:23:56 2015
From: NeilBrown <[email protected]>
Date: Fri, 14 Aug 2015 17:04:21 +1000
Subject: md/bitmap: return an error when bitmap superblock is corrupt.
To: [email protected], linux-raid <[email protected]>
Cc: GuoQing Jiang <[email protected]>, Goldwyn Rodrigues <[email protected]>, lkml <[email protected]>
Message-ID: <20150814170421.60d40eb0@noble>

From: NeilBrown <[email protected]>

commit b97e92574c0bf335db1cd2ec491d8ff5cd5d0b49 upstream
Use separate bitmaps for each nodes in the cluster

bitmap_read_sb() validates the bitmap superblock that it reads in. If it finds an inconsistency like a bad magic number or out-of-range version number, it prints an error and returns, but it incorrectly returns zero, so the array is still assembled with the (invalid) bitmap.

This means it could try to use a bitmap with a new version number which it therefore does not understand.

This bug was introduced in 3.5 and fix as part of a larger patch in 4.1. So the patch is suitable for any -stable kernel in that range.

---
 drivers/md/bitmap.c |    2 ++
 1 file changed, 2 insertions(+)

@@ -564,6 +564,8 @@ static int bitmap_read_sb(struct bitmap
 	if (err)
 		return err;
 
+	err = -EINVAL;
+
 	sb = kmap_atomic(sb_page);
 
 	chunksize = le32_to_cpu(sb->chunksize);

Patches currently in stable-queue which might be from [email protected] are

queue-3.10/md-raid1-extend-spinlock-to-protect-raid1_end_read_request-against-inconsistencies.patch queue-3.10/md-bitmap-return-an-error-when-bitmap-superblock-is-corrupt.patch queue-3.10/md-use-kzalloc-when-bitmap-is-disabled.patch

This is a note to let you know that I've just added the patch titled

md/bitmap: return an error when bitmap superblock is corrupt.

to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
md-bitmap-return-an-error-when-bitmap-superblock-is-corrupt.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From [email protected] Fri Aug 14 10:23:56 2015
From: NeilBrown <[email protected]>
Date: Fri, 14 Aug 2015 17:04:21 +1000
Subject: md/bitmap: return an error when bitmap superblock is corrupt.
To: [email protected], linux-raid <[email protected]>
Cc: GuoQing Jiang <[email protected]>, Goldwyn Rodrigues <[email protected]>, lkml <[email protected]>
Message-ID: <20150814170421.60d40eb0@noble>

From: NeilBrown <[email protected]>

commit b97e92574c0bf335db1cd2ec491d8ff5cd5d0b49 upstream
Use separate bitmaps for each nodes in the cluster

bitmap_read_sb() validates the bitmap superblock that it reads in. If it finds an inconsistency like a bad magic number or out-of-range version number, it prints an error and returns, but it incorrectly returns zero, so the array is still assembled with the (invalid) bitmap.

This means it could try to use a bitmap with a new version number which it therefore does not understand.

This bug was introduced in 3.5 and fix as part of a larger patch in 4.1. So the patch is suitable for any -stable kernel in that range.

---
 drivers/md/bitmap.c |    2 ++
 1 file changed, 2 insertions(+)

@@ -564,6 +564,8 @@ static int bitmap_read_sb(struct bitmap
 	if (err)
 		return err;
 
+	err = -EINVAL;
+
 	sb = kmap_atomic(sb_page);
 
 	chunksize = le32_to_cpu(sb->chunksize);

Patches currently in stable-queue which might be from [email protected] are

queue-3.14/md-raid1-extend-spinlock-to-protect-raid1_end_read_request-against-inconsistencies.patch queue-3.14/md-bitmap-return-an-error-when-bitmap-superblock-is-corrupt.patch queue-3.14/md-use-kzalloc-when-bitmap-is-disabled.patch

Thanks! Queuing it for the 3.16 kernel.

Cheers,
--
Luís