Ocfs2 devel - Mar 2015 - [PATCH] ocfs2: trusted xattr missing CAP_SYS_ADMIN check

The trusted extended attributes are only visible to the process which hvae
CAP_SYS_ADMIN capability but the check is missing in ocfs2 xattr_handler
trusted list. The check is important because this will be used for implementing
mechanisms in the userspace for which other ordinary processes should not
have access to.

Signed-off-by: Sanidhya Kashyap <sanidhya.gatech at gmail.com>
---
 fs/ocfs2/xattr.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 85b190d..71a6551 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -7326,6 +7326,9 @@ static size_t ocfs2_xattr_trusted_list(struct dentry
*dentry, char *list,
 	const size_t prefix_len = XATTR_TRUSTED_PREFIX_LEN;
 	const size_t total_len = prefix_len + name_len + 1;
 
+	if (!capable(CAP_SYS_ADMIN))
+		return 0;
+
 	if (list && total_len <= list_size) {
 		memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);
 		memcpy(list + prefix_len, name, name_len);
-- 
2.1.0

On Tue, 24 Mar 2015 11:46:32 -0400 Sanidhya Kashyap <sanidhya.gatech at
gmail.com> wrote:
> The trusted extended attributes are only visible to the process which hvae
> CAP_SYS_ADMIN capability but the check is missing in ocfs2 xattr_handler
> trusted list. The check is important because this will be used for
implementing
> mechanisms in the userspace for which other ordinary processes should not
> have access to.
> 
> ...
>
> --- a/fs/ocfs2/xattr.c
> +++ b/fs/ocfs2/xattr.c
> @@ -7326,6 +7326,9 @@ static size_t ocfs2_xattr_trusted_list(struct dentry
*dentry, char *list,
>  	const size_t prefix_len = XATTR_TRUSTED_PREFIX_LEN;
>  	const size_t total_len = prefix_len + name_len + 1;
>  
> +	if (!capable(CAP_SYS_ADMIN))
> +		return 0;
> +
>  	if (list && total_len <= list_size) {
>  		memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);
>  		memcpy(list + prefix_len, name, name_len);
Ouch.  Won't this break existing userspace?