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Message-Id: <20171021134558.21195-2-nicolas@belouin.fr>
Date: Sat, 21 Oct 2017 15:45:58 +0200
From: Nicolas Belouin <nicolas@...ouin.fr>
To: Jan Kara <jack@...e.com>, "Theodore Ts'o" <tytso@....edu>,
Andreas Dilger <adilger.kernel@...ger.ca>,
Jaegeuk Kim <jaegeuk@...nel.org>, Chao Yu <yuchao0@...wei.com>,
David Woodhouse <dwmw2@...radead.org>,
Dave Kleikamp <shaggy@...nel.org>, Mark Fasheh <mfasheh@...sity.com>,
Joel Becker <jlbec@...lplan.org>, Miklos Szeredi <miklos@...redi.hu>,
Phillip Lougher <phillip@...ashfs.org.uk>,
Richard Weinberger <richard@....at>,
Artem Bityutskiy <dedekind1@...il.com>,
Adrian Hunter <adrian.hunter@...el.com>,
Alexander Viro <viro@...iv.linux.org.uk>,
Serge Hallyn <serge@...lyn.com>, Paul Moore <paul@...l-moore.com>,
Stephen Smalley <sds@...ho.nsa.gov>,
Eric Paris <eparis@...isplace.org>,
James Morris <james.l.morris@...cle.com>, linux-ext4@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net,
linux-fsdevel@...r.kernel.org, linux-mtd@...ts.infradead.org,
jfs-discussion@...ts.sourceforge.net, ocfs2-devel@....oracle.com,
linux-unionfs@...r.kernel.org, reiserfs-devel@...r.kernel.org,
linux-security-module@...r.kernel.org, selinux@...ho.nsa.gov,
linux-api@...r.kernel.org, kernel-hardening@...ts.openwall.com
Cc: Nicolas Belouin <nicolas@...ouin.fr>
Subject: [RFC PATCH 2/2] fs: Grant CAP_TRUSTED rw access to trusted xattrs
The trusted xattrs read/write access is the perfect use case for
CAP_TRUSTED.
Signed-off-by: Nicolas Belouin <nicolas@...ouin.fr>
---
fs/ext2/xattr_trusted.c | 2 +-
fs/ext4/xattr_trusted.c | 2 +-
fs/f2fs/xattr.c | 6 +++---
fs/hfsplus/xattr.c | 2 +-
fs/jffs2/xattr_trusted.c | 2 +-
fs/jfs/xattr.c | 3 ++-
fs/ocfs2/xattr.c | 2 +-
fs/overlayfs/inode.c | 3 ++-
fs/reiserfs/xattr_trusted.c | 11 ++++++++---
fs/squashfs/xattr.c | 2 +-
fs/ubifs/xattr.c | 3 ++-
fs/xattr.c | 4 ++--
12 files changed, 25 insertions(+), 17 deletions(-)
diff --git a/fs/ext2/xattr_trusted.c b/fs/ext2/xattr_trusted.c
index 65049b71af13..8006c24f8ee0 100644
--- a/fs/ext2/xattr_trusted.c
+++ b/fs/ext2/xattr_trusted.c
@@ -11,7 +11,7 @@
static bool
ext2_xattr_trusted_list(struct dentry *dentry)
{
- return capable(CAP_SYS_ADMIN);
+ return capable(CAP_SYS_ADMIN) || capable(CAP_TRUSTED);
}
static int
diff --git a/fs/ext4/xattr_trusted.c b/fs/ext4/xattr_trusted.c
index c7765c735714..9849d1e0ebb9 100644
--- a/fs/ext4/xattr_trusted.c
+++ b/fs/ext4/xattr_trusted.c
@@ -15,7 +15,7 @@
static bool
ext4_xattr_trusted_list(struct dentry *dentry)
{
- return capable(CAP_SYS_ADMIN);
+ return capable(CAP_SYS_ADMIN) || capable(CAP_TRUSTED);
}
static int
diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index 7c65540148f8..ef572464deca 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -37,7 +37,7 @@ static int f2fs_xattr_generic_get(const struct xattr_handler *handler,
return -EOPNOTSUPP;
break;
case F2FS_XATTR_INDEX_TRUSTED:
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable(CAP_SYS_ADMIN) && !capable(CAP_TRUSTED))
return -EPERM;
break;
case F2FS_XATTR_INDEX_SECURITY:
@@ -62,7 +62,7 @@ static int f2fs_xattr_generic_set(const struct xattr_handler *handler,
return -EOPNOTSUPP;
break;
case F2FS_XATTR_INDEX_TRUSTED:
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable(CAP_SYS_ADMIN) && !capable(CAP_TRUSTED))
return -EPERM;
break;
case F2FS_XATTR_INDEX_SECURITY:
@@ -83,7 +83,7 @@ static bool f2fs_xattr_user_list(struct dentry *dentry)
static bool f2fs_xattr_trusted_list(struct dentry *dentry)
{
- return capable(CAP_SYS_ADMIN);
+ return capable(CAP_SYS_ADMIN) || capable(CAP_TRUSTED);
}
static int f2fs_xattr_advise_get(const struct xattr_handler *handler,
diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
index ae03a19196ef..0ec6d02ee7e9 100644
--- a/fs/hfsplus/xattr.c
+++ b/fs/hfsplus/xattr.c
@@ -606,7 +606,7 @@ static inline int can_list(const char *xattr_name)
return !strncmp(xattr_name, XATTR_TRUSTED_PREFIX,
XATTR_TRUSTED_PREFIX_LEN) ||
- capable(CAP_SYS_ADMIN);
+ capable(CAP_SYS_ADMIN) || capable(CAP_TRUSTED);
}
static ssize_t hfsplus_listxattr_finder_info(struct dentry *dentry,
diff --git a/fs/jffs2/xattr_trusted.c b/fs/jffs2/xattr_trusted.c
index 5d6030826c52..3c7ae98e4525 100644
--- a/fs/jffs2/xattr_trusted.c
+++ b/fs/jffs2/xattr_trusted.c
@@ -35,7 +35,7 @@ static int jffs2_trusted_setxattr(const struct xattr_handler *handler,
static bool jffs2_trusted_listxattr(struct dentry *dentry)
{
- return capable(CAP_SYS_ADMIN);
+ return capable(CAP_SYS_ADMIN) || capable(CAP_TRUSTED);
}
const struct xattr_handler jffs2_trusted_xattr_handler = {
diff --git a/fs/jfs/xattr.c b/fs/jfs/xattr.c
index 1c46573a96ed..e4f44f5133a1 100644
--- a/fs/jfs/xattr.c
+++ b/fs/jfs/xattr.c
@@ -859,7 +859,8 @@ ssize_t __jfs_getxattr(struct inode *inode, const char *name, void *data,
static inline int can_list(struct jfs_ea *ea)
{
return (!strncmp(ea->name, XATTR_TRUSTED_PREFIX,
- XATTR_TRUSTED_PREFIX_LEN) || capable(CAP_SYS_ADMIN));
+ XATTR_TRUSTED_PREFIX_LEN) ||
+ capable(CAP_SYS_ADMIN) || capable(CAP_TRUSTED));
}
ssize_t jfs_listxattr(struct dentry * dentry, char *data, size_t buf_size)
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 5fdf269ba82e..2b3994d192c6 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -906,7 +906,7 @@ static int ocfs2_xattr_list_entry(struct super_block *sb,
break;
case OCFS2_XATTR_INDEX_TRUSTED:
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable(CAP_SYS_ADMIN) && !capable(CAP_TRUSTED))
return 0;
break;
}
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index a619addecafc..c627003d3a74 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -264,7 +264,8 @@ static bool ovl_can_list(const char *s)
return true;
/* Never list trusted.overlay, list other trusted for superuser only */
- return !ovl_is_private_xattr(s) && capable(CAP_SYS_ADMIN);
+ return !ovl_is_private_xattr(s) &&
+ (capable(CAP_SYS_ADMIN) || capable(CAP_TRUSTED));
}
ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
diff --git a/fs/reiserfs/xattr_trusted.c b/fs/reiserfs/xattr_trusted.c
index f15a5f9e84ce..6f3fa0db8272 100644
--- a/fs/reiserfs/xattr_trusted.c
+++ b/fs/reiserfs/xattr_trusted.c
@@ -7,11 +7,16 @@
#include "xattr.h"
#include <linux/uaccess.h>
+inline bool trusted_capable(void)
+{
+ return capable(CAP_SYS_ADMIN) || capable(CAP_TRUSTED);
+}
+
static int
trusted_get(const struct xattr_handler *handler, struct dentry *unused,
struct inode *inode, const char *name, void *buffer, size_t size)
{
- if (!capable(CAP_SYS_ADMIN) || IS_PRIVATE(inode))
+ if (!trusted_capable() || IS_PRIVATE(inode))
return -EPERM;
return reiserfs_xattr_get(inode, xattr_full_name(handler, name),
@@ -23,7 +28,7 @@ trusted_set(const struct xattr_handler *handler, struct dentry *unused,
struct inode *inode, const char *name, const void *buffer,
size_t size, int flags)
{
- if (!capable(CAP_SYS_ADMIN) || IS_PRIVATE(inode))
+ if (!trusted_capable() || IS_PRIVATE(inode))
return -EPERM;
return reiserfs_xattr_set(inode,
@@ -33,7 +38,7 @@ trusted_set(const struct xattr_handler *handler, struct dentry *unused,
static bool trusted_list(struct dentry *dentry)
{
- return capable(CAP_SYS_ADMIN) && !IS_PRIVATE(d_inode(dentry));
+ return trusted_capable() && !IS_PRIVATE(d_inode(dentry));
}
const struct xattr_handler reiserfs_xattr_trusted_handler = {
diff --git a/fs/squashfs/xattr.c b/fs/squashfs/xattr.c
index 1548b3784548..e0a285ab1f7e 100644
--- a/fs/squashfs/xattr.c
+++ b/fs/squashfs/xattr.c
@@ -237,7 +237,7 @@ static const struct xattr_handler squashfs_xattr_user_handler = {
*/
static bool squashfs_trusted_xattr_handler_list(struct dentry *d)
{
- return capable(CAP_SYS_ADMIN);
+ return capable(CAP_SYS_ADMIN) || capable(CAP_TRUSTED);
}
static const struct xattr_handler squashfs_xattr_trusted_handler = {
diff --git a/fs/ubifs/xattr.c b/fs/ubifs/xattr.c
index c13eae819cbc..f3aa8be72a66 100644
--- a/fs/ubifs/xattr.c
+++ b/fs/ubifs/xattr.c
@@ -406,7 +406,8 @@ static bool xattr_visible(const char *name)
/* Show trusted namespace only for "power" users */
if (strncmp(name, XATTR_TRUSTED_PREFIX,
- XATTR_TRUSTED_PREFIX_LEN) == 0 && !capable(CAP_SYS_ADMIN))
+ XATTR_TRUSTED_PREFIX_LEN) == 0 &&
+ !capable(CAP_SYS_ADMIN) && !capable(CAP_TRUSTED))
return false;
return true;
diff --git a/fs/xattr.c b/fs/xattr.c
index 61cd28ba25f3..d9e9a0083dbb 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -113,7 +113,7 @@ xattr_permission(struct inode *inode, const char *name, int mask)
* The trusted.* namespace can only be accessed by privileged users.
*/
if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
- if (!capable(CAP_SYS_ADMIN))
+ if (!capable(CAP_SYS_ADMIN) && !capable(CAP_TRUSTED))
return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
return 0;
}
@@ -945,7 +945,7 @@ static int xattr_list_one(char **buffer, ssize_t *remaining_size,
ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs,
char *buffer, size_t size)
{
- bool trusted = capable(CAP_SYS_ADMIN);
+ bool trusted = capable(CAP_SYS_ADMIN) || capable(CAP_TRUSTED);
struct simple_xattr *xattr;
ssize_t remaining_size = size;
int err = 0;
--
2.14.2
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