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Commit 8595798c authored by Darrick J. Wong's avatar Darrick J. Wong Committed by Theodore Ts'o
Browse files

jbd2: gate checksum calculations on crc driver presence, not sb flags 



Change the journal's checksum functions to gate on whether or not the
crc32c driver is loaded, and gate the loading on the superblock bits.
This prevents a journal crash if someone loads a journal in no-csum
mode and then randomizes the superblock, thus flipping on the feature
bits.

Tested-By: default avatarNikolay Borisov <kernel@kyup.com>
Reported-by: default avatarNikolay Borisov <kernel@kyup.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent b90197b6

fs/jbd2/journal.c

+3 −3
Original line number Diff line number Diff line
@@ -124,7 +124,7 @@ EXPORT_SYMBOL(__jbd2_debug); 
/* Checksumming functions */

static int jbd2_verify_csum_type(journal_t *j, journal_superblock_t *sb)

{

	if (!jbd2_journal_has_csum_v2or3(j))

	if (!jbd2_journal_has_csum_v2or3_feature(j))

		return 1;



	return sb->s_checksum_type == JBD2_CRC32C_CHKSUM;
@@ -1531,7 +1531,7 @@ static int journal_get_superblock(journal_t *journal) 
		goto out;

	}



	if (jbd2_journal_has_csum_v2or3(journal) &&

	if (jbd2_journal_has_csum_v2or3_feature(journal) &&

	    JBD2_HAS_COMPAT_FEATURE(journal, JBD2_FEATURE_COMPAT_CHECKSUM)) {

		/* Can't have checksum v1 and v2 on at the same time! */

		printk(KERN_ERR "JBD2: Can't enable checksumming v1 and v2/3 "
@@ -1545,7 +1545,7 @@ static int journal_get_superblock(journal_t *journal) 
	}



	/* Load the checksum driver */

	if (jbd2_journal_has_csum_v2or3(journal)) {

	if (jbd2_journal_has_csum_v2or3_feature(journal)) {

		journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);

		if (IS_ERR(journal->j_chksum_driver)) {

			printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");

include/linux/jbd2.h

+9 −4
Original line number Diff line number Diff line
@@ -1338,13 +1338,18 @@ static inline int tid_geq(tid_t x, tid_t y) 
extern int jbd2_journal_blocks_per_page(struct inode *inode);

extern size_t journal_tag_bytes(journal_t *journal);



static inline bool jbd2_journal_has_csum_v2or3_feature(journal_t *j)

{

	return JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2) ||

	       JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V3);

}



static inline int jbd2_journal_has_csum_v2or3(journal_t *journal)

{

	if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2) ||

	    JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V3))

		return 1;

	WARN_ON_ONCE(jbd2_journal_has_csum_v2or3_feature(journal) &&

		     journal->j_chksum_driver == NULL);



	return 0;

	return journal->j_chksum_driver != NULL;

}



/*