Patch "ext4: use more strict checks for inodes_per_block on mount" has been added to the 4.4-stable tree

Patch "ext4: use more strict checks for inodes_per_block on mount" has been added to the 4.4-stable tree

[gregkh]

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

    ext4: use more strict checks for inodes_per_block on mount

to the 4.4-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:
     ext4-use-more-strict-checks-for-inodes_per_block-on-mount.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From cd6bb35bf7f6d7d922509bf50265383a0ceabe96 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Fri, 18 Nov 2016 13:28:30 -0500
Subject: ext4: use more strict checks for inodes_per_block on mount

From: Theodore Ts'o <tytso@mit.edu>

commit cd6bb35bf7f6d7d922509bf50265383a0ceabe96 upstream.

Centralize the checks for inodes_per_block and be more strict to make
sure the inodes_per_block_group can't end up being zero.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/ext4/super.c |   15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3496,12 +3496,16 @@ static int ext4_fill_super(struct super_
 
 	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
-	if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
-		goto cantfind_ext4;
 
 	sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
 	if (sbi->s_inodes_per_block == 0)
 		goto cantfind_ext4;
+	if (sbi->s_inodes_per_group < sbi->s_inodes_per_block ||
+	    sbi->s_inodes_per_group > blocksize * 8) {
+		ext4_msg(sb, KERN_ERR, "invalid inodes per group: %lu\n",
+			 sbi->s_blocks_per_group);
+		goto failed_mount;
+	}
 	sbi->s_itb_per_group = sbi->s_inodes_per_group /
 					sbi->s_inodes_per_block;
 	sbi->s_desc_per_block = blocksize / EXT4_DESC_SIZE(sb);
@@ -3584,13 +3588,6 @@ static int ext4_fill_super(struct super_
 	}
 	sbi->s_cluster_ratio = clustersize / blocksize;
 
-	if (sbi->s_inodes_per_group > blocksize * 8) {
-		ext4_msg(sb, KERN_ERR,
-		       "#inodes per group too big: %lu",
-		       sbi->s_inodes_per_group);
-		goto failed_mount;
-	}
-
 	/* Do we have standard group size of clustersize * 8 blocks ? */
 	if (sbi->s_blocks_per_group == clustersize << 3)
 		set_opt2(sb, STD_GROUP_SIZE);


Patches currently in stable-queue which might be from tytso@mit.edu are

queue-4.4/ext4-reject-inodes-with-negative-size.patch
queue-4.4/ext4-fix-in-superblock-mount-options-processing.patch
queue-4.4/ext4-fix-mballoc-breakage-with-64k-block-size.patch
queue-4.4/ext4-do-not-perform-data-journaling-when-data-is-encrypted.patch
queue-4.4/ext4-use-more-strict-checks-for-inodes_per_block-on-mount.patch
queue-4.4/ext4-add-sanity-checking-to-count_overhead.patch
queue-4.4/ext4-return-enomem-instead-of-success.patch
queue-4.4/ext4-fix-stack-memory-corruption-with-64k-block-size.patch