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-Tag: v4.8.16~31
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bf0f02079039146620f90125efe8ae778db9a729;p=thirdparty%2Fkernel%2Fstable.git

f2fs: fix overflow due to condition check order

commit e87f7329bbd6760c2acc4f1eb423362b08851a71 upstream.

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")
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index c1cec5a48ba7b..06f39db659232 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -970,7 +970,7 @@ 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 {