2010-04-22 10:06:01

by Dan Carpenter

Subject: [patch] security: testing the wrong variable in create_by_name()

There is a typo here. We should be testing "*dentry" instead of
"dentry". If "*dentry" is an ERR_PTR, it gets dereferenced in either
mkdir() or create() which would cause an OOPs.

Signed-off-by: Dan Carpenter <[email protected]>

diff --git a/security/inode.c b/security/inode.c
index c3a7938..1c812e8 100644
--- a/security/inode.c
+++ b/security/inode.c
@@ -161,13 +161,13 @@ static int create_by_name(const char *name, mode_t mode,

mutex_lock(&parent->d_inode->i_mutex);
*dentry = lookup_one_len(name, parent, strlen(name));
- if (!IS_ERR(dentry)) {
+ if (!IS_ERR(*dentry)) {
if ((mode & S_IFMT) == S_IFDIR)
error = mkdir(parent->d_inode, *dentry, mode);
else
error = create(parent->d_inode, *dentry, mode);
} else
- error = PTR_ERR(dentry);
+ error = PTR_ERR(*dentry);
mutex_unlock(&parent->d_inode->i_mutex);

return error;

2010-04-22 11:19:11

by James Morris

Subject: Re: [patch] security: testing the wrong variable in create_by_name()

On Thu, 22 Apr 2010, Dan Carpenter wrote:

> There is a typo here. We should be testing "*dentry" instead of
> "dentry". If "*dentry" is an ERR_PTR, it gets dereferenced in either
> mkdir() or create() which would cause an OOPs.
>
> Signed-off-by: Dan Carpenter <[email protected]>

Looks correct -- queued for Linus.


>
> diff --git a/security/inode.c b/security/inode.c
> index c3a7938..1c812e8 100644
> --- a/security/inode.c
> +++ b/security/inode.c
> @@ -161,13 +161,13 @@ static int create_by_name(const char *name, mode_t mode,
>
> mutex_lock(&parent->d_inode->i_mutex);
> *dentry = lookup_one_len(name, parent, strlen(name));
> - if (!IS_ERR(dentry)) {
> + if (!IS_ERR(*dentry)) {
> if ((mode & S_IFMT) == S_IFDIR)
> error = mkdir(parent->d_inode, *dentry, mode);
> else
> error = create(parent->d_inode, *dentry, mode);
> } else
> - error = PTR_ERR(dentry);
> + error = PTR_ERR(*dentry);
> mutex_unlock(&parent->d_inode->i_mutex);
>
> return error;
>

--
James Morris
<[email protected]>