[PATCH v2] f2fs: avoid out-of-range memory access

[Ocean Chen]

blk_off might over 512 due to fs corrupt.
Use ENTRIES_IN_SUM to protect invalid memory access.

v2:
- fix typo
Signed-off-by: Ocean Chen <oceanchen@xxxxxxxxxx>
---
 fs/f2fs/segment.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 8dee063c833f..a5e8af0bd62e 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -3403,6 +3403,8 @@ static int read_compacted_summaries(struct f2fs_sb_info *sbi)
 
 		for (j = 0; j < blk_off; j++) {
 			struct f2fs_summary *s;
+			if (j >= ENTRIES_IN_SUM)
+				return -EFAULT;
 			s = (struct f2fs_summary *)(kaddr + offset);
 			seg_i->sum_blk->entries[j] = *s;
 			offset += SUMMARY_SIZE;
-- 
2.22.0.410.gd8fdbe21b5-goog