f2fs: sanity check segment count

commit b9dd46188edc2f0d1f37328637860bb65a771124 upstream.

F2FS uses 4 bytes to represent block address. As a result, supported
size of disk is 16 TB and it equals to 16 * 1024 * 1024 / 2 segments.

Signed-off-by: Jin Qian <jinqian@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 13 insertions, 0 deletions

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 013c6a541d6b..7e0c002c12e9 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1405,6 +1405,13 @@ static int sanity_check_raw_super(struct f2fs_sb_info *sbi,
                 return 1;
         }
 
+        if (le32_to_cpu(raw_super->segment_count) > F2FS_MAX_SEGMENT) {
+                f2fs_msg(sb, KERN_INFO,
+                        "Invalid segment count (%u)",
+                        le32_to_cpu(raw_super->segment_count));
+                return 1;
+        }
+
         /* check CP/SIT/NAT/SSA/MAIN_AREA area boundary */
         if (sanity_check_area_boundary(sbi, bh))
                 return 1;
diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
index 422630b8e588..e46e7d10312b 100644
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -286,6 +286,12 @@ struct f2fs_nat_block {
 #define SIT_ENTRY_PER_BLOCK (PAGE_SIZE / sizeof(struct f2fs_sit_entry))
 
 /*
+ * F2FS uses 4 bytes to represent block address. As a result, supported size of
+ * disk is 16 TB and it equals to 16 * 1024 * 1024 / 2 segments.
+ */
+#define F2FS_MAX_SEGMENT       ((16 * 1024 * 1024) / 2)
+
+/*
  * Note that f2fs_sit_entry->vblocks has the following bit-field information.
  * [15:10] : allocation type such as CURSEG_XXXX_TYPE
  * [9:0] : valid block count