2 files changed, 16 insertions, 0 deletions

diff --git a/fs/jbd/journal.c b/fs/jbd/journal.c
index 9fe061fb8779..fea8dd661d2b 100644
--- a/fs/jbd/journal.c
+++ b/fs/jbd/journal.c
@@ -1135,6 +1135,14 @@ static int journal_get_superblock(journal_t *journal)
                 goto out;
         }
 
+        if (be32_to_cpu(sb->s_first) == 0 ||
+            be32_to_cpu(sb->s_first) >= journal->j_maxlen) {
+                printk(KERN_WARNING
+                        "JBD: Invalid start block of journal: %u\n",
+                        be32_to_cpu(sb->s_first));
+                goto out;
+        }
+
         return 0;
 
 out:
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index f24df13adc4e..d6e93d00833e 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1251,6 +1251,14 @@ static int journal_get_superblock(journal_t *journal)
                 goto out;
         }
 
+        if (be32_to_cpu(sb->s_first) == 0 ||
+            be32_to_cpu(sb->s_first) >= journal->j_maxlen) {
+                printk(KERN_WARNING
+                        "JBD2: Invalid start block of journal: %u\n",
+                        be32_to_cpu(sb->s_first));
+                goto out;
+        }
+
         return 0;
 
 out: