From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Wed, 23 Nov 2016 18:51:17 +0000 (-0800)
Subject: f2fs: fix overflow due to condition check order
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=e87f7329bbd6760c2acc4f1eb423362b08851a71;p=linux-beck.git

f2fs: fix overflow due to condition check order

In the last ilen case, i was already increased, resulting in accessing out-
of-boundary entry of do_replace and blkaddr.
Fix to check ilen first to exit the loop.

Fixes: 2aa8fbb9693020 ("f2fs: refactor __exchange_data_block for speed up")
Cc: stable@vger.kernel.org # 4.8+
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index c7865073cd26..02372175725d 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -967,7 +967,7 @@ static int __clone_blkaddrs(struct inode *src_inode, struct inode *dst_inode,
 				new_size = (dst + i) << PAGE_SHIFT;
 				if (dst_inode->i_size < new_size)
 					f2fs_i_size_write(dst_inode, new_size);
-			} while ((do_replace[i] || blkaddr[i] == NULL_ADDR) && --ilen);
+			} while (--ilen && (do_replace[i] || blkaddr[i] == NULL_ADDR));
 
 			f2fs_put_dnode(&dn);
 		} else {