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.
Reported-by: Nikolay Borisov <kernel@xxxxxxxx>
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/jbd2/journal.c | 12 +++++++++---
include/linux/jbd2.h | 10 ++++++----
2 files changed, 15 insertions(+), 7 deletions(-)
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 8270fe9..16e3a46 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -122,9 +122,15 @@ EXPORT_SYMBOL(__jbd2_debug);
#endif
/* Checksumming functions */
+static bool 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 int jbd2_verify_csum_type(journal_t *j, journal_superblock_t *sb)
{
- if (!jbd2_journal_has_csum_v2or3(j))
+ if (!journal_has_csum_v2or3_feature(j))
return 1;
return sb->s_checksum_type == JBD2_CRC32C_CHKSUM;
@@ -1531,7 +1537,7 @@ static int journal_get_superblock(journal_t *journal)
goto out;
}
- if (jbd2_journal_has_csum_v2or3(journal) &&
+ if (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 +1551,7 @@ static int journal_get_superblock(journal_t *journal)
}
/* Load the checksum driver */
- if (jbd2_journal_has_csum_v2or3(journal)) {
+ if (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..c74c786 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1340,11 +1340,13 @@ extern size_t journal_tag_bytes(journal_t *journal);
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_HAS_INCOMPAT_FEATURE(journal,
+ JBD2_FEATURE_INCOMPAT_CSUM_V2) ||
+ JBD2_HAS_INCOMPAT_FEATURE(journal,
+ JBD2_FEATURE_INCOMPAT_CSUM_V3)) &&
+ journal->j_chksum_driver == NULL);
- return 0;
+ return journal->j_chksum_driver != NULL;
}
/*
--
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