From: Jin Qian <jinqian@google.com>
Date: Tue, 25 Apr 2017 23:28:48 +0000 (-0700)
Subject: f2fs: sanity check segment count
X-Git-Tag: v3.18.53~3
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=27f411c7ee241d194cd5fd3271d83089d70b2c20;p=thirdparty%2Fkernel%2Fstable.git

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 ab09d8605e748..341466bcf1800 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -913,6 +913,13 @@ 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 860313a33a438..2df22eab98e3f 100644
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -268,6 +268,12 @@ struct f2fs_nat_block {
 #define SIT_VBLOCK_MAP_SIZE 64
 #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