Ensure that the journal superblock passes checksum before recovering the
filesystem.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
e2fsck/journal.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 59 insertions(+), 0 deletions(-)
diff --git a/e2fsck/journal.c b/e2fsck/journal.c
index 915b8bb..2ac2e54 100644
--- a/e2fsck/journal.c
+++ b/e2fsck/journal.c
@@ -40,6 +40,53 @@ static int bh_count = 0;
*/
#undef USE_INODE_IO
+/* Checksumming functions */
+int e2fsck_journal_verify_csum_type(journal_t *j, journal_superblock_t *jsb)
+{
+ if (!JFS_HAS_INCOMPAT_FEATURE(j, JFS_FEATURE_INCOMPAT_CSUM_V2))
+ return 1;
+
+ return jsb->s_checksum_type == JBD2_CRC32C_CHKSUM;
+}
+
+static __u32 e2fsck_journal_sb_csum(journal_t *j, journal_superblock_t *jsb)
+{
+ __u32 crc, old_crc;
+
+ old_crc = jsb->s_checksum;
+ jsb->s_checksum = 0;
+ crc = ext2fs_crc32c_le(~0, (unsigned char *)jsb,
+ sizeof(journal_superblock_t));
+ jsb->s_checksum = old_crc;
+
+ return crc;
+}
+
+int e2fsck_journal_sb_csum_verify(journal_t *j, journal_superblock_t *jsb)
+{
+ __u32 provided, calculated;
+
+ if (!JFS_HAS_INCOMPAT_FEATURE(j, JFS_FEATURE_INCOMPAT_CSUM_V2))
+ return 1;
+
+ provided = ext2fs_be32_to_cpu(jsb->s_checksum);
+ calculated = e2fsck_journal_sb_csum(j, jsb);
+
+ return provided == calculated;
+}
+
+errcode_t e2fsck_journal_sb_csum_set(journal_t *j, journal_superblock_t *jsb)
+{
+ __u32 crc;
+
+ if (!JFS_HAS_INCOMPAT_FEATURE(j, JFS_FEATURE_INCOMPAT_CSUM_V2))
+ return 0;
+
+ crc = e2fsck_journal_sb_csum(j, jsb);
+ jsb->s_checksum = ext2fs_cpu_to_be32(crc);
+ return 0;
+}
+
/* Kernel compatibility functions for handling the journal. These allow us
* to use the recovery.c file virtually unchanged from the kernel, so we
* don't have to do much to keep kernel and user recovery in sync.
@@ -560,6 +607,15 @@ static errcode_t e2fsck_journal_load(journal_t *journal)
if (JFS_HAS_RO_COMPAT_FEATURE(journal, ~JFS_KNOWN_ROCOMPAT_FEATURES))
return EXT2_ET_RO_UNSUPP_FEATURE;
+ /* Checksum v1 and v2 are mutually exclusive features. */
+ if (JFS_HAS_INCOMPAT_FEATURE(journal, JFS_FEATURE_INCOMPAT_CSUM_V2) &&
+ JFS_HAS_COMPAT_FEATURE(journal, JFS_FEATURE_COMPAT_CHECKSUM))
+ return EXT2_ET_CORRUPT_SUPERBLOCK;
+
+ if (!e2fsck_journal_verify_csum_type(journal, jsb) ||
+ !e2fsck_journal_sb_csum_verify(journal, jsb))
+ return EXT2_ET_CORRUPT_SUPERBLOCK;
+
/* We have now checked whether we know enough about the journal
* format to be able to proceed safely, so any other checks that
* fail we should attempt to recover from. */
@@ -627,6 +683,7 @@ static void e2fsck_journal_reset_super(e2fsck_t ctx, journal_superblock_t *jsb,
for (i = 0; i < 4; i ++)
new_seq ^= u.val[i];
jsb->s_sequence = htonl(new_seq);
+ e2fsck_journal_sb_csum_set(journal, jsb);
mark_buffer_dirty(journal->j_sb_buffer);
ll_rw_block(WRITE, 1, &journal->j_sb_buffer);
@@ -667,6 +724,7 @@ static void e2fsck_journal_release(e2fsck_t ctx, journal_t *journal,
jsb->s_sequence = htonl(journal->j_transaction_sequence);
if (reset)
jsb->s_start = 0; /* this marks the journal as empty */
+ e2fsck_journal_sb_csum_set(journal, jsb);
mark_buffer_dirty(journal->j_sb_buffer);
}
brelse(journal->j_sb_buffer);
@@ -843,6 +901,7 @@ static errcode_t recover_ext3_journal(e2fsck_t ctx)
ctx->fs->super->s_state |= EXT2_ERROR_FS;
ext2fs_mark_super_dirty(ctx->fs);
journal->j_superblock->s_errno = 0;
+ e2fsck_journal_sb_csum_set(journal, journal->j_superblock);
mark_buffer_dirty(journal->j_sb_buffer);
}
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