diff mbox

[1/8] jbd2: gate checksum calculations on crc driver presence, not sb flags

Message ID 20151012215422.28872.71133.stgit@birch.djwong.org
State Accepted, archived
Headers show

Commit Message

Darrick Wong Oct. 12, 2015, 9:54 p.m. UTC 
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.

v2: Create a feature-test helper, use it everywhere.

Tested-By: Nikolay Borisov <kernel@kyup.com>
Reported-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/jbd2/journal.c    |    6 +++---
 include/linux/jbd2.h |   13 +++++++++----
 2 files changed, 12 insertions(+), 7 deletions(-)



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Comments

Theodore Ts'o Oct. 15, 2015, 2:32 p.m. UTC | #1 
On Mon, Oct 12, 2015 at 02:54:22PM -0700, Darrick J. Wong wrote:
> 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.
> 
> v2: Create a feature-test helper, use it everywhere.
> 
> Tested-By: Nikolay Borisov <kernel@kyup.com>
> Reported-by: Nikolay Borisov <kernel@kyup.com>
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Thanks, applied.

						- Ted
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diff mbox

Patch

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 8270fe9..00f7dbd 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -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");
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index df07e78..6da6f89 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -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;
 }
 
 /*