[PATCH 4.9 098/103] f2fs: sanity check segment count

From: Greg Kroah-Hartman
Date: Thu May 11 2017 - 10:43:43 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jin Qian <jinqian@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/f2fs/super.c | 7 +++++++
include/linux/f2fs_fs.h | 6 ++++++
2 files changed, 13 insertions(+)

--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1405,6 +1405,13 @@ static int sanity_check_raw_super(struct
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;
--- 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