linux-kernel - [PATCH, v2] ext4: ensure link targets are NUL-terminated

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Message-ID: <20081211222622.GC18665@dastardly.home.dghda.com>
Date:	Thu, 11 Dec 2008 22:27:08 +0000
From:	"Duane Griffin" <duaneg@...da.com>
To:	Duane Griffin <duaneg@...da.com>
Cc:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	Boaz Harrosh <bharrosh@...asas.com>, tytso@....edu,
	adilger@....com, linux-ext4@...r.kernel.org
Subject: [PATCH, v2] ext4: ensure link targets are NUL-terminated

Ensure link targets are NUL-terminated, even if corrupted on-disk.

Signed-off-by: Duane Griffin <duaneg@...da.com>
---

V2: terminate when the link is read instead of every time it is
followed, as suggested by Dave Kleikamp.

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ca88060..e70122e 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4200,9 +4200,10 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 		inode->i_op = &ext4_dir_inode_operations;
 		inode->i_fop = &ext4_dir_operations;
 	} else if (S_ISLNK(inode->i_mode)) {
-		if (ext4_inode_is_fast_symlink(inode))
+		if (ext4_inode_is_fast_symlink(inode)) {
 			inode->i_op = &ext4_fast_symlink_inode_operations;
-		else {
+			((char *) ei->i_data)[inode->i_size] = '\0';
+		} else {
 			inode->i_op = &ext4_symlink_inode_operations;
 			ext4_set_aops(inode);
 		}
-- 
"I never could learn to drink that blood and call it wine" - Bob Dylan
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