[PATCH] ntfs3: Add bounds checking for dp0

[lei lu <llfamsec@gmail.com>]

Added out-of-bound checking for *dp0 (DIR_PAGE_ENTRY_32).

Signed-off-by: lei lu <llfamsec@gmail.com>
---
 fs/ntfs3/fslog.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/ntfs3/fslog.c b/fs/ntfs3/fslog.c
index 855519713bf7..af6f2ce9ea68 100644
--- a/fs/ntfs3/fslog.c
+++ b/fs/ntfs3/fslog.c
@@ -4184,10 +4184,14 @@ int log_replay(struct ntfs_inode *ni, bool *initialized)
 	dp = NULL;
 	while ((dp = enum_rstbl(dptbl, dp))) {
 		struct DIR_PAGE_ENTRY_32 *dp0 = (struct DIR_PAGE_ENTRY_32 *)dp;
-		// NOTE: Danger. Check for of boundary.
-		memmove(&dp->vcn, &dp0->vcn_low,
-			2 * sizeof(u64) +
-				le32_to_cpu(dp->lcns_follow) * sizeof(u64));
+		// Check for of boundary.
+		u32 len = 2 * sizeof(u64) +
+			le32_to_cpu(dp->lcns_follow) * sizeof(u64);
+		if (PtrOffset(dptbl, &dp0->vcn_low) + len > t32) {
+			err = -EINVAL;
+			goto out;
+		}
+		memmove(&dp->vcn, &dp0->vcn_low, len);
 	}
 
 end_conv_1:
-- 
2.34.1