jbd2: checksum descriptor blocks

[firefly-linux-kernel-4.4.55.git] / fs / jbd2 / recovery.c

diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c
index 728ecd0705d9507ad43729e06f404301a639bac6..066ee603db50ad2aef1f5a135b9e0314d2d9355d 100644 (file)
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -174,6 +174,25 @@ static int jread(struct buffer_head **bhp, journal_t *journal,
        return 0;
 }
 
+static int jbd2_descr_block_csum_verify(journal_t *j,
+                                       void *buf)
+{
+       struct jbd2_journal_block_tail *tail;
+       __u32 provided, calculated;
+
+       if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+               return 1;
+
+       tail = (struct jbd2_journal_block_tail *)(buf + j->j_blocksize -
+                       sizeof(struct jbd2_journal_block_tail));
+       provided = tail->t_checksum;
+       tail->t_checksum = 0;
+       calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
+       tail->t_checksum = provided;
+
+       provided = be32_to_cpu(provided);
+       return provided == calculated;
+}
 
 /*
  * Count the number of in-use tags in a journal descriptor block.
@@ -186,6 +205,9 @@ static int count_tags(journal_t *journal, struct buffer_head *bh)
        int                     nr = 0, size = journal->j_blocksize;
        int                     tag_bytes = journal_tag_bytes(journal);
 
+       if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+               size -= sizeof(struct jbd2_journal_block_tail);
+
        tagp = &bh->b_data[sizeof(journal_header_t)];
 
        while ((tagp - bh->b_data + tag_bytes) <= size) {
@@ -366,6 +388,7 @@ static int do_one_pass(journal_t *journal,
        int                     blocktype;
        int                     tag_bytes = journal_tag_bytes(journal);
        __u32                   crc32_sum = ~0; /* Transactional Checksums */
+       int                     descr_csum_size = 0;
 
        /*
         * First thing is to establish what we expect to find in the log
@@ -451,6 +474,18 @@ static int do_one_pass(journal_t *journal,
 
                switch(blocktype) {
                case JBD2_DESCRIPTOR_BLOCK:
+                       /* Verify checksum first */
+                       if (JBD2_HAS_INCOMPAT_FEATURE(journal,
+                                       JBD2_FEATURE_INCOMPAT_CSUM_V2))
+                               descr_csum_size =
+                                       sizeof(struct jbd2_journal_block_tail);
+                       if (descr_csum_size > 0 &&
+                           !jbd2_descr_block_csum_verify(journal,
+                                                         bh->b_data)) {
+                               err = -EIO;
+                               goto failed;
+                       }
+
                        /* If it is a valid descriptor block, replay it
                         * in pass REPLAY; if journal_checksums enabled, then
                         * calculate checksums in PASS_SCAN, otherwise,
@@ -481,7 +516,7 @@ static int do_one_pass(journal_t *journal,
 
                        tagp = &bh->b_data[sizeof(journal_header_t)];
                        while ((tagp - bh->b_data + tag_bytes)
-                              <= journal->j_blocksize) {
+                              <= journal->j_blocksize - descr_csum_size) {
                                unsigned long io_block;
 
                                tag = (journal_block_tag_t *) tagp;