>From 667173a18b671896f933c5952fa211601d2e5ab0 Mon Sep 17 00:00:00 2001
From: Wang Sheng-Hui <shhuiw@xxxxxxxxx>
Date: Fri, 22 Jul 2011 08:50:13 -0500
Subject: [PATCH] ext2: check xattr name_len before acquiring sem lock in ext2_xattr_get
The patch is against 3.0.
In ext2_xattr_get, the code will acquire sem lock first, later check
the length of xattr name_len > 255. It's kind of time consuming, and
we should do the basic check before the time consuming acquiring sem
lock.
Signed-off-by: Wang Sheng-Hui <shhuiw@xxxxxxxxx>
---
fs/ext2/xattr.c | 10 +++++-----
1 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
index 5299706..d27b71f 100644
--- a/fs/ext2/xattr.c
+++ b/fs/ext2/xattr.c
@@ -161,6 +161,10 @@ ext2_xattr_get(struct inode *inode, int name_index, const char *name,
if (name == NULL)
return -EINVAL;
+ name_len = strlen(name);
+ if (name_len > 255)
+ return -ERANGE;
+
down_read(&EXT2_I(inode)->xattr_sem);
error = -ENODATA;
if (!EXT2_I(inode)->i_file_acl)
@@ -181,12 +185,8 @@ bad_block: ext2_error(inode->i_sb, "ext2_xattr_get",
error = -EIO;
goto cleanup;
}
- /* find named attribute */
- name_len = strlen(name);
- error = -ERANGE;
- if (name_len > 255)
- goto cleanup;
+ /* find named attribute */
entry = FIRST_ENTRY(bh);
while (!IS_LAST_ENTRY(entry)) {
struct ext2_xattr_entry *next =
--
1.7.1
--
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