f2fs: sanity check segment count

BugLink: http://bugs.launchpad.net/bugs/1691369
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>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 287fcbd0551e4c8694882f7f03fdb437398b4e6d..119b68332cd5cd1182398a80fdd1e588b8b2c996 100644 (file)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1441,6 +1441,13 @@ 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 cea41a124a8010ed6d16022c22a789c9b40bb8c6..3e5972ef501975e3c56e9afe77913fd0d41ab0df 100644 (file)
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -293,6 +293,12 @@ struct f2fs_nat_block {
 #define SIT_VBLOCK_MAP_SIZE 64
 #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