[PATCH] resize.f2fs: fix access out-of memory boundary

[PATCH] resize.f2fs: fix access out-of memory boundary

[Jaegeuk Kim]

This fixes out-of memory boundary on nat_bitmap, when resizing small to
large partition.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fsck/f2fs.h  |  1 +
 fsck/mount.c | 13 +++++++++----
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/fsck/f2fs.h b/fsck/f2fs.h
index 8a5ce36..d0e08aa 100644
--- a/fsck/f2fs.h
+++ b/fsck/f2fs.h
@@ -50,6 +50,7 @@ struct node_info {
 
 struct f2fs_nm_info {
 	block_t nat_blkaddr;
+	block_t nat_blocks;
 	nid_t max_nid;
 	nid_t init_scan_nid;
 	nid_t next_scan_nid;
diff --git a/fsck/mount.c b/fsck/mount.c
index 545f862..a925bb9 100644
--- a/fsck/mount.c
+++ b/fsck/mount.c
@@ -998,7 +998,12 @@ void write_nat_bits(struct f2fs_sb_info *sbi,
 				(seg_off << get_sb(log_blocks_per_seg) << 1) +
 				(i & ((1 << get_sb(log_blocks_per_seg)) - 1)));
 
-		if (f2fs_test_bit(i, nm_i->nat_bitmap))
+		/*
+		 * Should consider new nat_blocks is larger than old
+		 * nm_i->nat_blocks, since nm_i->nat_bitmap is based on
+		 * old one.
+		 */
+		if (i < nm_i->nat_blocks && f2fs_test_bit(i, nm_i->nat_bitmap))
 			blkaddr += (1 << get_sb(log_blocks_per_seg));
 
 		ret = dev_read_block(nat_block, blkaddr);
@@ -1037,14 +1042,14 @@ int init_node_manager(struct f2fs_sb_info *sbi)
 	struct f2fs_checkpoint *cp = F2FS_CKPT(sbi);
 	struct f2fs_nm_info *nm_i = NM_I(sbi);
 	unsigned char *version_bitmap;
-	unsigned int nat_segs, nat_blocks;
+	unsigned int nat_segs;
 
 	nm_i->nat_blkaddr = get_sb(nat_blkaddr);
 
 	/* segment_count_nat includes pair segment so divide to 2. */
 	nat_segs = get_sb(segment_count_nat) >> 1;
-	nat_blocks = nat_segs << get_sb(log_blocks_per_seg);
-	nm_i->max_nid = NAT_ENTRY_PER_BLOCK * nat_blocks;
+	nm_i->nat_blocks = nat_segs << get_sb(log_blocks_per_seg);
+	nm_i->max_nid = NAT_ENTRY_PER_BLOCK * nm_i->nat_blocks;
 	nm_i->fcnt = 0;
 	nm_i->nat_cnt = 0;
 	nm_i->init_scan_nid = get_cp(next_free_nid);
-- 
2.15.0.531.g2ccb3012c9-goog


------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot

Re: [PATCH] resize.f2fs: fix access out-of memory boundary

[Chao Yu]

On 2018/3/24 0:32, Jaegeuk Kim wrote:
> This fixes out-of memory boundary on nat_bitmap, when resizing small to
> large partition.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <yuchao0@huawei.com>

Thanks,


------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot