jbd2: fix r_count overflows leading to buffer overflow in journal recovery

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

diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c
index b5128c6e63ad6644d19bf861a062d63f48265a4d..a9079d035ae59d9a6983bcaa79625ce5f0e5c343 100644 (file)
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -842,15 +842,23 @@ static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
 {
        jbd2_journal_revoke_header_t *header;
        int offset, max;
+       int csum_size = 0;
+       __u32 rcount;
        int record_len = 4;
 
        header = (jbd2_journal_revoke_header_t *) bh->b_data;
        offset = sizeof(jbd2_journal_revoke_header_t);
-       max = be32_to_cpu(header->r_count);
+       rcount = be32_to_cpu(header->r_count);
 
        if (!jbd2_revoke_block_csum_verify(journal, header))
                return -EINVAL;
 
+       if (jbd2_journal_has_csum_v2or3(journal))
+               csum_size = sizeof(struct jbd2_journal_revoke_tail);
+       if (rcount > journal->j_blocksize - csum_size)
+               return -EINVAL;
+       max = rcount;
+
        if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
                record_len = 8;