[SRU,T,1/1] ext4: always initialize the crc32c checksum driver

Message ID 20180706210258.3630-2-khalid.elmously@canonical.com
State New
Headers show
Series
  • Fix for CVE-2018-1094
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Commit Message

Khalid Elmously July 6, 2018, 9:02 p.m.
From: Theodore Ts'o <tytso@mit.edu>

CVE-2018-1094

The extended attribute code now uses the crc32c checksum for hashing
purposes, so we should just always always initialize it.  We also want
to prevent NULL pointer dereferences if one of the metadata checksum
features is enabled after the file sytsem is originally mounted.

This issue has been assigned CVE-2018-1094.

https://bugzilla.kernel.org/show_bug.cgi?id=199183
https://bugzilla.redhat.com/show_bug.cgi?id=1560788

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
(backported from a45403b51582a87872927a3e0fc0a389c26867f1)
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
---
 fs/ext4/super.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

Patch

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 3b313429b83f..26552bf46ca8 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3457,15 +3457,12 @@  static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	}
 
 	/* Load the checksum driver */
-	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
-				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
-		sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
-		if (IS_ERR(sbi->s_chksum_driver)) {
-			ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
-			ret = PTR_ERR(sbi->s_chksum_driver);
-			sbi->s_chksum_driver = NULL;
-			goto failed_mount;
-		}
+	sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
+	if (IS_ERR(sbi->s_chksum_driver)) {
+		ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
+		ret = PTR_ERR(sbi->s_chksum_driver);
+		sbi->s_chksum_driver = NULL;
+		goto failed_mount;
 	}
 
 	/* Check superblock checksum */