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>

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 16462e7..86e1cb8 100644 (file)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1059,6 +1059,13 @@ static int sanity_check_raw_super(struct super_block *sb,
                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(sb, raw_super))
                return 1;

diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
index 25c6324..3d6e6ce 100644 (file)
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -284,6 +284,12 @@ struct f2fs_nat_block {
 #define SIT_ENTRY_PER_BLOCK (PAGE_CACHE_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