From c3d59ad6ab0b3d01c10f326bbc9b089424a3a5c4 Mon Sep 17 00:00:00 2001 From: Carlos Maiolino Date: Tue, 2 Oct 2012 23:59:23 -0300 Subject: ext3: ext3_bread usage audit This is the ext3 version of the same patch applied to Ext4, where such goal is to audit the usage of ext3_bread() due a possible misinterpretion of its return value. Focused on directory blocks, a NULL value returned from ext3_bread() means a hole, which cannot exist into a directory inode. It can pass undetected after a fix in an uninitialized error variable. The (now) initialized variable into ext3_getblk() may lead to a zero'ed return value of ext3_bread() to its callers, which can make the caller do not detect the hole in the directory inode. This patch creates a new wrapper function ext3_dir_bread() which checks for holes properly, reports error, and returns EIO in that case. Signed-off-by: Carlos Maiolino Signed-off-by: Jan Kara --- fs/ext3/namei.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'fs/ext3/namei.h') diff --git a/fs/ext3/namei.h b/fs/ext3/namei.h index f2ce2b0065c9..46304d8c9f0a 100644 --- a/fs/ext3/namei.h +++ b/fs/ext3/namei.h @@ -6,3 +6,22 @@ */ extern struct dentry *ext3_get_parent(struct dentry *child); + +static inline struct buffer_head *ext3_dir_bread(handle_t *handle, + struct inode *inode, + int block, int create, + int *err) +{ + struct buffer_head *bh; + + bh = ext3_bread(handle, inode, block, create, err); + + if (!bh && !(*err)) { + *err = -EIO; + ext3_error(inode->i_sb, __func__, + "Directory hole detected on inode %lu\n", + inode->i_ino); + return NULL; + } + return bh; +} -- cgit v1.2.3