ext4: always initialize the crc32c checksum driver (a45403b5) · Commits · 戴 / test

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

fs/ext4/super.c

+6 −9

Original line number	Diff line number	Diff line
		@@ -3492,8 +3492,6 @@ static int ext4_fill_super(struct super_block sb, void data, int silent)
		}

		/* Load the checksum driver */
		if (ext4_has_feature_metadata_csum(sb) \|\|
		ext4_has_feature_ea_inode(sb)) {
		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.");
		@@ -3501,7 +3499,6 @@ static int ext4_fill_super(struct super_block sb, void data, int silent)
		sbi->s_chksum_driver = NULL;
		goto failed_mount;
		}
		}

		/* Check superblock checksum */
		if (!ext4_superblock_csum_verify(sb, es)) {

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