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* [PATCH] Add flags option to get xattr method paired to __vfs_getxattr
@ 2019-08-12 19:32 Mark Salyzyn
  2019-08-13  8:28 ` kbuild test robot
  2019-08-13  8:48 ` Greg Kroah-Hartman
  0 siblings, 2 replies; 9+ messages in thread
From: Mark Salyzyn @ 2019-08-12 19:32 UTC (permalink / raw)
  To: linux-kernel
  Cc: kernel-team, Mark Salyzyn, Stephen Smalley,
	linux-security-module, stable, Eric Van Hensbergen,
	Latchesar Ionkov, Dominique Martinet, David Howells, Chris Mason,
	Josef Bacik, David Sterba, Jeff Layton, Sage Weil, Ilya Dryomov,
	Steve French, Tyler Hicks, Jan Kara, Theodore Ts\'o,
	Andreas Dilger, Jaegeuk Kim, Chao Yu, Miklos Szeredi,
	Bob Peterson, Andreas Gruenbacher, David Woodhouse,
	Richard Weinberger, Dave Kleikamp, Greg Kroah-Hartman, Tejun Heo,
	Trond Myklebust, Anna Schumaker, Mark Fasheh, Joel Becker,
	Joseph Qi, Mike Marshall, Martin Brandenburg, Alexander Viro,
	Phillip Lougher, Darrick J. Wong, linux-xfs, Hugh Dickins,
	David S. Miller, Serge Hallyn, James Morris, Mimi Zohar,
	Paul Moore, Eric Paris, Casey Schaufler, Andrew Morton,
	Vyacheslav Dubeyko, Ernesto A. Fernández, Mathieu Malaterre,
	v9fs-developer, linux-afs, linux-btrfs, ceph-devel, linux-cifs,
	samba-technical, ecryptfs, linux-ext4, linux-f2fs-devel,
	linux-fsdevel, cluster-devel, linux-mtd, jfs-discussion,
	linux-nfs, ocfs2-devel, devel, linux-unionfs, reiserfs-devel,
	linux-mm, netdev, linux-integrity, selinux

Add a flag option to get xattr method that could have a bit flag of
XATTR_NOSECURITY passed to it.  XATTR_NOSECURITY is generally then
set in the __vfs_getxattr path.

This handles the case of a union filesystem driver that is being
requested by the security layer to report back the xattr data.

For the use case where access is to be blocked by the security layer.

The path then could be security(dentry) ->
__vfs_getxattr(dentry...XATTR_NOSECUIRTY) ->
handler->get(dentry...XATTR_NOSECURITY) ->
__vfs_getxattr(lower_dentry...XATTR_NOSECUIRTY) ->
lower_handler->get(lower_dentry...XATTR_NOSECUIRTY)
which would report back through the chain data and success as
expected, the logging security layer at the top would have the
data to determine the access permissions and report back the target
context that was blocked.

Without the get handler flag, the path on a union filesystem would be
the errant security(dentry) -> __vfs_getxattr(dentry) ->
handler->get(dentry) -> vfs_getxattr(lower_dentry) -> nested ->
security(lower_dentry, log off) -> lower_handler->get(lower_dentry)
which would report back through the chain no data, and -EACCES.

For selinux for both cases, this would translate to a correctly
determined blocked access. In the first case with this change a correct avc
log would be reported, in the second legacy case an incorrect avc log
would be reported against an uninitialized u:object_r:unlabeled:s0
context making the logs cosmetically useless for audit2allow.

This patch series is inert and is the wide-spread addition of the
flags option for xattr functions, and a replacement of _vfs_getxattr
with __vfs_getxattr(...XATTR_NOSECURITY).

Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: linux-kernel@vger.kernel.org
Cc: kernel-team@android.com
Cc: linux-security-module@vger.kernel.org
Cc: stable@vger.kernel.org # 4.4, 4.9, 4.14 & 4.19
---
Removed from an overlayfs patch set, and made independent.
Expect this to be the basis of some security improvements.
---
 fs/9p/acl.c                       |  3 ++-
 fs/9p/xattr.c                     |  3 ++-
 fs/afs/xattr.c                    |  6 +++---
 fs/btrfs/xattr.c                  |  3 ++-
 fs/ceph/xattr.c                   |  3 ++-
 fs/cifs/xattr.c                   |  2 +-
 fs/ecryptfs/inode.c               |  6 ++++--
 fs/ecryptfs/mmap.c                |  2 +-
 fs/ext2/xattr_trusted.c           |  2 +-
 fs/ext2/xattr_user.c              |  2 +-
 fs/ext4/xattr_security.c          |  2 +-
 fs/ext4/xattr_trusted.c           |  2 +-
 fs/ext4/xattr_user.c              |  2 +-
 fs/f2fs/xattr.c                   |  4 ++--
 fs/fuse/xattr.c                   |  4 ++--
 fs/gfs2/xattr.c                   |  3 ++-
 fs/hfs/attr.c                     |  2 +-
 fs/hfsplus/xattr.c                |  3 ++-
 fs/hfsplus/xattr_trusted.c        |  3 ++-
 fs/hfsplus/xattr_user.c           |  3 ++-
 fs/jffs2/security.c               |  3 ++-
 fs/jffs2/xattr_trusted.c          |  3 ++-
 fs/jffs2/xattr_user.c             |  3 ++-
 fs/jfs/xattr.c                    |  5 +++--
 fs/kernfs/inode.c                 |  3 ++-
 fs/nfs/nfs4proc.c                 |  6 ++++--
 fs/ocfs2/xattr.c                  |  9 +++++---
 fs/orangefs/xattr.c               |  3 ++-
 fs/overlayfs/super.c              |  8 ++++---
 fs/posix_acl.c                    |  2 +-
 fs/reiserfs/xattr_security.c      |  3 ++-
 fs/reiserfs/xattr_trusted.c       |  3 ++-
 fs/reiserfs/xattr_user.c          |  3 ++-
 fs/squashfs/xattr.c               |  2 +-
 fs/xattr.c                        | 36 +++++++++++++++----------------
 fs/xfs/xfs_xattr.c                |  3 ++-
 include/linux/xattr.h             |  9 ++++----
 include/uapi/linux/xattr.h        |  5 +++--
 mm/shmem.c                        |  3 ++-
 net/socket.c                      |  3 ++-
 security/commoncap.c              |  6 ++++--
 security/integrity/evm/evm_main.c |  3 ++-
 security/selinux/hooks.c          | 11 ++++++----
 security/smack/smack_lsm.c        |  5 +++--
 44 files changed, 119 insertions(+), 81 deletions(-)

diff --git a/fs/9p/acl.c b/fs/9p/acl.c
index 6261719f6f2a..cb14e8b312bc 100644
--- a/fs/9p/acl.c
+++ b/fs/9p/acl.c
@@ -214,7 +214,8 @@ int v9fs_acl_mode(struct inode *dir, umode_t *modep,
 
 static int v9fs_xattr_get_acl(const struct xattr_handler *handler,
 			      struct dentry *dentry, struct inode *inode,
-			      const char *name, void *buffer, size_t size)
+			      const char *name, void *buffer, size_t size,
+			      int flags)
 {
 	struct v9fs_session_info *v9ses;
 	struct posix_acl *acl;
diff --git a/fs/9p/xattr.c b/fs/9p/xattr.c
index ac8ff8ca4c11..5cfa772452fd 100644
--- a/fs/9p/xattr.c
+++ b/fs/9p/xattr.c
@@ -139,7 +139,8 @@ ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 
 static int v9fs_xattr_handler_get(const struct xattr_handler *handler,
 				  struct dentry *dentry, struct inode *inode,
-				  const char *name, void *buffer, size_t size)
+				  const char *name, void *buffer, size_t size,
+				  int flags)
 {
 	const char *full_name = xattr_full_name(handler, name);
 
diff --git a/fs/afs/xattr.c b/fs/afs/xattr.c
index 5552d034090a..e6509c21f08a 100644
--- a/fs/afs/xattr.c
+++ b/fs/afs/xattr.c
@@ -334,7 +334,7 @@ static const struct xattr_handler afs_xattr_yfs_handler = {
 static int afs_xattr_get_cell(const struct xattr_handler *handler,
 			      struct dentry *dentry,
 			      struct inode *inode, const char *name,
-			      void *buffer, size_t size)
+			      void *buffer, size_t size, int flags)
 {
 	struct afs_vnode *vnode = AFS_FS_I(inode);
 	struct afs_cell *cell = vnode->volume->cell;
@@ -361,7 +361,7 @@ static const struct xattr_handler afs_xattr_afs_cell_handler = {
 static int afs_xattr_get_fid(const struct xattr_handler *handler,
 			     struct dentry *dentry,
 			     struct inode *inode, const char *name,
-			     void *buffer, size_t size)
+			     void *buffer, size_t size, int flags)
 {
 	struct afs_vnode *vnode = AFS_FS_I(inode);
 	char text[16 + 1 + 24 + 1 + 8 + 1];
@@ -397,7 +397,7 @@ static const struct xattr_handler afs_xattr_afs_fid_handler = {
 static int afs_xattr_get_volume(const struct xattr_handler *handler,
 			      struct dentry *dentry,
 			      struct inode *inode, const char *name,
-			      void *buffer, size_t size)
+			      void *buffer, size_t size, int flags)
 {
 	struct afs_vnode *vnode = AFS_FS_I(inode);
 	const char *volname = vnode->volume->name;
diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
index 95d9aebff2c4..1e522e145344 100644
--- a/fs/btrfs/xattr.c
+++ b/fs/btrfs/xattr.c
@@ -353,7 +353,8 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 
 static int btrfs_xattr_handler_get(const struct xattr_handler *handler,
 				   struct dentry *unused, struct inode *inode,
-				   const char *name, void *buffer, size_t size)
+				   const char *name, void *buffer, size_t size,
+				   int flags)
 {
 	name = xattr_full_name(handler, name);
 	return btrfs_getxattr(inode, name, buffer, size);
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index 37b458a9af3a..edb7eb9ae83e 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -1171,7 +1171,8 @@ int __ceph_setxattr(struct inode *inode, const char *name,
 
 static int ceph_get_xattr_handler(const struct xattr_handler *handler,
 				  struct dentry *dentry, struct inode *inode,
-				  const char *name, void *value, size_t size)
+				  const char *name, void *value, size_t size,
+				  int flags)
 {
 	if (!ceph_is_valid_xattr(name))
 		return -EOPNOTSUPP;
diff --git a/fs/cifs/xattr.c b/fs/cifs/xattr.c
index 9076150758d8..7f71c06ce631 100644
--- a/fs/cifs/xattr.c
+++ b/fs/cifs/xattr.c
@@ -199,7 +199,7 @@ static int cifs_creation_time_get(struct dentry *dentry, struct inode *inode,
 
 static int cifs_xattr_get(const struct xattr_handler *handler,
 			  struct dentry *dentry, struct inode *inode,
-			  const char *name, void *value, size_t size)
+			  const char *name, void *value, size_t size, int flags)
 {
 	ssize_t rc = -EOPNOTSUPP;
 	unsigned int xid;
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 18426f4855f1..c710c7533729 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -1018,7 +1018,8 @@ ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
 		goto out;
 	}
 	inode_lock(lower_inode);
-	rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
+	rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size,
+			    XATTR_NOSECURITY);
 	inode_unlock(lower_inode);
 out:
 	return rc;
@@ -1103,7 +1104,8 @@ const struct inode_operations ecryptfs_main_iops = {
 
 static int ecryptfs_xattr_get(const struct xattr_handler *handler,
 			      struct dentry *dentry, struct inode *inode,
-			      const char *name, void *buffer, size_t size)
+			      const char *name, void *buffer, size_t size,
+			      int flags)
 {
 	return ecryptfs_getxattr(dentry, inode, name, buffer, size);
 }
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index cffa0c1ec829..2362be3e3b4d 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -422,7 +422,7 @@ static int ecryptfs_write_inode_size_to_xattr(struct inode *ecryptfs_inode)
 	}
 	inode_lock(lower_inode);
 	size = __vfs_getxattr(lower_dentry, lower_inode, ECRYPTFS_XATTR_NAME,
-			      xattr_virt, PAGE_SIZE);
+			      xattr_virt, PAGE_SIZE, XATTR_NOSECURITY);
 	if (size < 0)
 		size = 8;
 	put_unaligned_be64(i_size_read(ecryptfs_inode), xattr_virt);
diff --git a/fs/ext2/xattr_trusted.c b/fs/ext2/xattr_trusted.c
index 49add1107850..8d313664f0fa 100644
--- a/fs/ext2/xattr_trusted.c
+++ b/fs/ext2/xattr_trusted.c
@@ -18,7 +18,7 @@ ext2_xattr_trusted_list(struct dentry *dentry)
 static int
 ext2_xattr_trusted_get(const struct xattr_handler *handler,
 		       struct dentry *unused, struct inode *inode,
-		       const char *name, void *buffer, size_t size)
+		       const char *name, void *buffer, size_t size, int flags)
 {
 	return ext2_xattr_get(inode, EXT2_XATTR_INDEX_TRUSTED, name,
 			      buffer, size);
diff --git a/fs/ext2/xattr_user.c b/fs/ext2/xattr_user.c
index c243a3b4d69d..712b7c95cc64 100644
--- a/fs/ext2/xattr_user.c
+++ b/fs/ext2/xattr_user.c
@@ -20,7 +20,7 @@ ext2_xattr_user_list(struct dentry *dentry)
 static int
 ext2_xattr_user_get(const struct xattr_handler *handler,
 		    struct dentry *unused, struct inode *inode,
-		    const char *name, void *buffer, size_t size)
+		    const char *name, void *buffer, size_t size, int flags)
 {
 	if (!test_opt(inode->i_sb, XATTR_USER))
 		return -EOPNOTSUPP;
diff --git a/fs/ext4/xattr_security.c b/fs/ext4/xattr_security.c
index 197a9d8a15ef..50fb71393fb6 100644
--- a/fs/ext4/xattr_security.c
+++ b/fs/ext4/xattr_security.c
@@ -15,7 +15,7 @@
 static int
 ext4_xattr_security_get(const struct xattr_handler *handler,
 			struct dentry *unused, struct inode *inode,
-			const char *name, void *buffer, size_t size)
+			const char *name, void *buffer, size_t size, int flags)
 {
 	return ext4_xattr_get(inode, EXT4_XATTR_INDEX_SECURITY,
 			      name, buffer, size);
diff --git a/fs/ext4/xattr_trusted.c b/fs/ext4/xattr_trusted.c
index e9389e5d75c3..64bd8f86c1f1 100644
--- a/fs/ext4/xattr_trusted.c
+++ b/fs/ext4/xattr_trusted.c
@@ -22,7 +22,7 @@ ext4_xattr_trusted_list(struct dentry *dentry)
 static int
 ext4_xattr_trusted_get(const struct xattr_handler *handler,
 		       struct dentry *unused, struct inode *inode,
-		       const char *name, void *buffer, size_t size)
+		       const char *name, void *buffer, size_t size, int flags)
 {
 	return ext4_xattr_get(inode, EXT4_XATTR_INDEX_TRUSTED,
 			      name, buffer, size);
diff --git a/fs/ext4/xattr_user.c b/fs/ext4/xattr_user.c
index d4546184b34b..b7301373820e 100644
--- a/fs/ext4/xattr_user.c
+++ b/fs/ext4/xattr_user.c
@@ -21,7 +21,7 @@ ext4_xattr_user_list(struct dentry *dentry)
 static int
 ext4_xattr_user_get(const struct xattr_handler *handler,
 		    struct dentry *unused, struct inode *inode,
-		    const char *name, void *buffer, size_t size)
+		    const char *name, void *buffer, size_t size, int flags)
 {
 	if (!test_opt(inode->i_sb, XATTR_USER))
 		return -EOPNOTSUPP;
diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index b32c45621679..76559da8dfba 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -24,7 +24,7 @@
 
 static int f2fs_xattr_generic_get(const struct xattr_handler *handler,
 		struct dentry *unused, struct inode *inode,
-		const char *name, void *buffer, size_t size)
+		const char *name, void *buffer, size_t size, int flags)
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 
@@ -79,7 +79,7 @@ static bool f2fs_xattr_trusted_list(struct dentry *dentry)
 
 static int f2fs_xattr_advise_get(const struct xattr_handler *handler,
 		struct dentry *unused, struct inode *inode,
-		const char *name, void *buffer, size_t size)
+		const char *name, void *buffer, size_t size, int flags)
 {
 	if (buffer)
 		*((char *)buffer) = F2FS_I(inode)->i_advise;
diff --git a/fs/fuse/xattr.c b/fs/fuse/xattr.c
index 433717640f78..d1ef7808304e 100644
--- a/fs/fuse/xattr.c
+++ b/fs/fuse/xattr.c
@@ -176,7 +176,7 @@ int fuse_removexattr(struct inode *inode, const char *name)
 
 static int fuse_xattr_get(const struct xattr_handler *handler,
 			 struct dentry *dentry, struct inode *inode,
-			 const char *name, void *value, size_t size)
+			 const char *name, void *value, size_t size, int flags)
 {
 	return fuse_getxattr(inode, name, value, size);
 }
@@ -199,7 +199,7 @@ static bool no_xattr_list(struct dentry *dentry)
 
 static int no_xattr_get(const struct xattr_handler *handler,
 			struct dentry *dentry, struct inode *inode,
-			const char *name, void *value, size_t size)
+			const char *name, void *value, size_t size, int flags)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/fs/gfs2/xattr.c b/fs/gfs2/xattr.c
index bbe593d16bea..a9db067a99c1 100644
--- a/fs/gfs2/xattr.c
+++ b/fs/gfs2/xattr.c
@@ -588,7 +588,8 @@ static int __gfs2_xattr_get(struct inode *inode, const char *name,
 
 static int gfs2_xattr_get(const struct xattr_handler *handler,
 			  struct dentry *unused, struct inode *inode,
-			  const char *name, void *buffer, size_t size)
+			  const char *name, void *buffer, size_t size,
+			  int flags)
 {
 	struct gfs2_inode *ip = GFS2_I(inode);
 	struct gfs2_holder gh;
diff --git a/fs/hfs/attr.c b/fs/hfs/attr.c
index 74fa62643136..08222a9c5d31 100644
--- a/fs/hfs/attr.c
+++ b/fs/hfs/attr.c
@@ -115,7 +115,7 @@ static ssize_t __hfs_getxattr(struct inode *inode, enum hfs_xattr_type type,
 
 static int hfs_xattr_get(const struct xattr_handler *handler,
 			 struct dentry *unused, struct inode *inode,
-			 const char *name, void *value, size_t size)
+			 const char *name, void *value, size_t size, int flags)
 {
 	return __hfs_getxattr(inode, handler->flags, value, size);
 }
diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
index bb0b27d88e50..381c2aaedbc8 100644
--- a/fs/hfsplus/xattr.c
+++ b/fs/hfsplus/xattr.c
@@ -839,7 +839,8 @@ static int hfsplus_removexattr(struct inode *inode, const char *name)
 
 static int hfsplus_osx_getxattr(const struct xattr_handler *handler,
 				struct dentry *unused, struct inode *inode,
-				const char *name, void *buffer, size_t size)
+				const char *name, void *buffer, size_t size,
+				int flags)
 {
 	/*
 	 * Don't allow retrieving properly prefixed attributes
diff --git a/fs/hfsplus/xattr_trusted.c b/fs/hfsplus/xattr_trusted.c
index fbad91e1dada..54d926314f8c 100644
--- a/fs/hfsplus/xattr_trusted.c
+++ b/fs/hfsplus/xattr_trusted.c
@@ -14,7 +14,8 @@
 
 static int hfsplus_trusted_getxattr(const struct xattr_handler *handler,
 				    struct dentry *unused, struct inode *inode,
-				    const char *name, void *buffer, size_t size)
+				    const char *name, void *buffer,
+				    size_t size, int flags)
 {
 	return hfsplus_getxattr(inode, name, buffer, size,
 				XATTR_TRUSTED_PREFIX,
diff --git a/fs/hfsplus/xattr_user.c b/fs/hfsplus/xattr_user.c
index 74d19faf255e..4d2b1ffff887 100644
--- a/fs/hfsplus/xattr_user.c
+++ b/fs/hfsplus/xattr_user.c
@@ -14,7 +14,8 @@
 
 static int hfsplus_user_getxattr(const struct xattr_handler *handler,
 				 struct dentry *unused, struct inode *inode,
-				 const char *name, void *buffer, size_t size)
+				 const char *name, void *buffer, size_t size,
+				 int flags)
 {
 
 	return hfsplus_getxattr(inode, name, buffer, size,
diff --git a/fs/jffs2/security.c b/fs/jffs2/security.c
index c2332e30f218..e6f42fe435af 100644
--- a/fs/jffs2/security.c
+++ b/fs/jffs2/security.c
@@ -50,7 +50,8 @@ int jffs2_init_security(struct inode *inode, struct inode *dir,
 /* ---- XATTR Handler for "security.*" ----------------- */
 static int jffs2_security_getxattr(const struct xattr_handler *handler,
 				   struct dentry *unused, struct inode *inode,
-				   const char *name, void *buffer, size_t size)
+				   const char *name, void *buffer, size_t size,
+				   int flags)
 {
 	return do_jffs2_getxattr(inode, JFFS2_XPREFIX_SECURITY,
 				 name, buffer, size);
diff --git a/fs/jffs2/xattr_trusted.c b/fs/jffs2/xattr_trusted.c
index 5d6030826c52..9dccaae549f5 100644
--- a/fs/jffs2/xattr_trusted.c
+++ b/fs/jffs2/xattr_trusted.c
@@ -18,7 +18,8 @@
 
 static int jffs2_trusted_getxattr(const struct xattr_handler *handler,
 				  struct dentry *unused, struct inode *inode,
-				  const char *name, void *buffer, size_t size)
+				  const char *name, void *buffer, size_t size,
+				  int flags)
 {
 	return do_jffs2_getxattr(inode, JFFS2_XPREFIX_TRUSTED,
 				 name, buffer, size);
diff --git a/fs/jffs2/xattr_user.c b/fs/jffs2/xattr_user.c
index 9d027b4abcf9..c0983a3e810b 100644
--- a/fs/jffs2/xattr_user.c
+++ b/fs/jffs2/xattr_user.c
@@ -18,7 +18,8 @@
 
 static int jffs2_user_getxattr(const struct xattr_handler *handler,
 			       struct dentry *unused, struct inode *inode,
-			       const char *name, void *buffer, size_t size)
+			       const char *name, void *buffer, size_t size,
+			       int flags)
 {
 	return do_jffs2_getxattr(inode, JFFS2_XPREFIX_USER,
 				 name, buffer, size);
diff --git a/fs/jfs/xattr.c b/fs/jfs/xattr.c
index db41e7803163..5c79a35bf62f 100644
--- a/fs/jfs/xattr.c
+++ b/fs/jfs/xattr.c
@@ -925,7 +925,7 @@ static int __jfs_xattr_set(struct inode *inode, const char *name,
 
 static int jfs_xattr_get(const struct xattr_handler *handler,
 			 struct dentry *unused, struct inode *inode,
-			 const char *name, void *value, size_t size)
+			 const char *name, void *value, size_t size, int flags)
 {
 	name = xattr_full_name(handler, name);
 	return __jfs_getxattr(inode, name, value, size);
@@ -942,7 +942,8 @@ static int jfs_xattr_set(const struct xattr_handler *handler,
 
 static int jfs_xattr_get_os2(const struct xattr_handler *handler,
 			     struct dentry *unused, struct inode *inode,
-			     const char *name, void *value, size_t size)
+			     const char *name, void *value, size_t size,
+			     int flags)
 {
 	if (is_known_namespace(name))
 		return -EOPNOTSUPP;
diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
index f3f3984cce80..89db24ce644e 100644
--- a/fs/kernfs/inode.c
+++ b/fs/kernfs/inode.c
@@ -309,7 +309,8 @@ int kernfs_xattr_set(struct kernfs_node *kn, const char *name,
 
 static int kernfs_vfs_xattr_get(const struct xattr_handler *handler,
 				struct dentry *unused, struct inode *inode,
-				const char *suffix, void *value, size_t size)
+				const char *suffix, void *value, size_t size,
+				int flags)
 {
 	const char *name = xattr_full_name(handler, suffix);
 	struct kernfs_node *kn = inode->i_private;
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 1406858bae6c..1905597f86fb 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -7218,7 +7218,8 @@ static int nfs4_xattr_set_nfs4_acl(const struct xattr_handler *handler,
 
 static int nfs4_xattr_get_nfs4_acl(const struct xattr_handler *handler,
 				   struct dentry *unused, struct inode *inode,
-				   const char *key, void *buf, size_t buflen)
+				   const char *key, void *buf, size_t buflen,
+				   int flags)
 {
 	return nfs4_proc_get_acl(inode, buf, buflen);
 }
@@ -7243,7 +7244,8 @@ static int nfs4_xattr_set_nfs4_label(const struct xattr_handler *handler,
 
 static int nfs4_xattr_get_nfs4_label(const struct xattr_handler *handler,
 				     struct dentry *unused, struct inode *inode,
-				     const char *key, void *buf, size_t buflen)
+				     const char *key, void *buf, size_t buflen,
+				     int flags)
 {
 	if (security_ismaclabel(key))
 		return nfs4_get_security_label(inode, buf, buflen);
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 90c830e3758e..525835807c86 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -7242,7 +7242,8 @@ int ocfs2_init_security_and_acl(struct inode *dir,
  */
 static int ocfs2_xattr_security_get(const struct xattr_handler *handler,
 				    struct dentry *unused, struct inode *inode,
-				    const char *name, void *buffer, size_t size)
+				    const char *name, void *buffer, size_t size,
+				    int flags)
 {
 	return ocfs2_xattr_get(inode, OCFS2_XATTR_INDEX_SECURITY,
 			       name, buffer, size);
@@ -7314,7 +7315,8 @@ const struct xattr_handler ocfs2_xattr_security_handler = {
  */
 static int ocfs2_xattr_trusted_get(const struct xattr_handler *handler,
 				   struct dentry *unused, struct inode *inode,
-				   const char *name, void *buffer, size_t size)
+				   const char *name, void *buffer, size_t size,
+				   int flags)
 {
 	return ocfs2_xattr_get(inode, OCFS2_XATTR_INDEX_TRUSTED,
 			       name, buffer, size);
@@ -7340,7 +7342,8 @@ const struct xattr_handler ocfs2_xattr_trusted_handler = {
  */
 static int ocfs2_xattr_user_get(const struct xattr_handler *handler,
 				struct dentry *unused, struct inode *inode,
-				const char *name, void *buffer, size_t size)
+				const char *name, void *buffer, size_t size,
+				int flags)
 {
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 
diff --git a/fs/orangefs/xattr.c b/fs/orangefs/xattr.c
index bdc285aea360..ef4180bff7bb 100644
--- a/fs/orangefs/xattr.c
+++ b/fs/orangefs/xattr.c
@@ -541,7 +541,8 @@ static int orangefs_xattr_get_default(const struct xattr_handler *handler,
 				      struct inode *inode,
 				      const char *name,
 				      void *buffer,
-				      size_t size)
+				      size_t size,
+				      int flags)
 {
 	return orangefs_inode_getxattr(inode, name, buffer, size);
 
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index b368e2e102fa..a7b21f2ea2dd 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -854,7 +854,7 @@ static unsigned int ovl_split_lowerdirs(char *str)
 static int __maybe_unused
 ovl_posix_acl_xattr_get(const struct xattr_handler *handler,
 			struct dentry *dentry, struct inode *inode,
-			const char *name, void *buffer, size_t size)
+			const char *name, void *buffer, size_t size, int flags)
 {
 	return ovl_xattr_get(dentry, inode, handler->name, buffer, size);
 }
@@ -919,7 +919,8 @@ ovl_posix_acl_xattr_set(const struct xattr_handler *handler,
 
 static int ovl_own_xattr_get(const struct xattr_handler *handler,
 			     struct dentry *dentry, struct inode *inode,
-			     const char *name, void *buffer, size_t size)
+			     const char *name, void *buffer, size_t size,
+			     int flags)
 {
 	return -EOPNOTSUPP;
 }
@@ -934,7 +935,8 @@ static int ovl_own_xattr_set(const struct xattr_handler *handler,
 
 static int ovl_other_xattr_get(const struct xattr_handler *handler,
 			       struct dentry *dentry, struct inode *inode,
-			       const char *name, void *buffer, size_t size)
+			       const char *name, void *buffer, size_t size,
+			       int flags)
 {
 	return ovl_xattr_get(dentry, inode, name, buffer, size);
 }
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 84ad1c90d535..cd55621e570b 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -832,7 +832,7 @@ EXPORT_SYMBOL (posix_acl_to_xattr);
 static int
 posix_acl_xattr_get(const struct xattr_handler *handler,
 		    struct dentry *unused, struct inode *inode,
-		    const char *name, void *value, size_t size)
+		    const char *name, void *value, size_t size, int flags)
 {
 	struct posix_acl *acl;
 	int error;
diff --git a/fs/reiserfs/xattr_security.c b/fs/reiserfs/xattr_security.c
index 20be9a0e5870..eedfa07a4fd0 100644
--- a/fs/reiserfs/xattr_security.c
+++ b/fs/reiserfs/xattr_security.c
@@ -11,7 +11,8 @@
 
 static int
 security_get(const struct xattr_handler *handler, struct dentry *unused,
-	     struct inode *inode, const char *name, void *buffer, size_t size)
+	     struct inode *inode, const char *name, void *buffer, size_t size,
+	     int flags)
 {
 	if (IS_PRIVATE(inode))
 		return -EPERM;
diff --git a/fs/reiserfs/xattr_trusted.c b/fs/reiserfs/xattr_trusted.c
index 5ed48da3d02b..2d11d98605dd 100644
--- a/fs/reiserfs/xattr_trusted.c
+++ b/fs/reiserfs/xattr_trusted.c
@@ -10,7 +10,8 @@
 
 static int
 trusted_get(const struct xattr_handler *handler, struct dentry *unused,
-	    struct inode *inode, const char *name, void *buffer, size_t size)
+	    struct inode *inode, const char *name, void *buffer, size_t size,
+	    int flags)
 {
 	if (!capable(CAP_SYS_ADMIN) || IS_PRIVATE(inode))
 		return -EPERM;
diff --git a/fs/reiserfs/xattr_user.c b/fs/reiserfs/xattr_user.c
index a573ca45bacc..2a59d85c69c9 100644
--- a/fs/reiserfs/xattr_user.c
+++ b/fs/reiserfs/xattr_user.c
@@ -9,7 +9,8 @@
 
 static int
 user_get(const struct xattr_handler *handler, struct dentry *unused,
-	 struct inode *inode, const char *name, void *buffer, size_t size)
+	 struct inode *inode, const char *name, void *buffer, size_t size,
+	 int flags)
 {
 	if (!reiserfs_xattrs_user(inode->i_sb))
 		return -EOPNOTSUPP;
diff --git a/fs/squashfs/xattr.c b/fs/squashfs/xattr.c
index e1e3f3dd5a06..d8d58c990652 100644
--- a/fs/squashfs/xattr.c
+++ b/fs/squashfs/xattr.c
@@ -204,7 +204,7 @@ static int squashfs_xattr_handler_get(const struct xattr_handler *handler,
 				      struct dentry *unused,
 				      struct inode *inode,
 				      const char *name,
-				      void *buffer, size_t size)
+				      void *buffer, size_t size, int flags)
 {
 	return squashfs_xattr_get(inode, handler->flags, name,
 		buffer, size);
diff --git a/fs/xattr.c b/fs/xattr.c
index 90dd78f0eb27..71f887518d6f 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -281,7 +281,7 @@ vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value,
 		return PTR_ERR(handler);
 	if (!handler->get)
 		return -EOPNOTSUPP;
-	error = handler->get(handler, dentry, inode, name, NULL, 0);
+	error = handler->get(handler, dentry, inode, name, NULL, 0, 0);
 	if (error < 0)
 		return error;
 
@@ -292,32 +292,20 @@ vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value,
 		memset(value, 0, error + 1);
 	}
 
-	error = handler->get(handler, dentry, inode, name, value, error);
+	error = handler->get(handler, dentry, inode, name, value, error, 0);
 	*xattr_value = value;
 	return error;
 }
 
 ssize_t
 __vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name,
-	       void *value, size_t size)
+	       void *value, size_t size, int flags)
 {
 	const struct xattr_handler *handler;
-
-	handler = xattr_resolve_name(inode, &name);
-	if (IS_ERR(handler))
-		return PTR_ERR(handler);
-	if (!handler->get)
-		return -EOPNOTSUPP;
-	return handler->get(handler, dentry, inode, name, value, size);
-}
-EXPORT_SYMBOL(__vfs_getxattr);
-
-ssize_t
-vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size)
-{
-	struct inode *inode = dentry->d_inode;
 	int error;
 
+	if (flags & XATTR_NOSECURITY)
+		goto nolsm;
 	error = xattr_permission(inode, name, MAY_READ);
 	if (error)
 		return error;
@@ -339,7 +327,19 @@ vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size)
 		return ret;
 	}
 nolsm:
-	return __vfs_getxattr(dentry, inode, name, value, size);
+	handler = xattr_resolve_name(inode, &name);
+	if (IS_ERR(handler))
+		return PTR_ERR(handler);
+	if (!handler->get)
+		return -EOPNOTSUPP;
+	return handler->get(handler, dentry, inode, name, value, size, flags);
+}
+EXPORT_SYMBOL(__vfs_getxattr);
+
+ssize_t
+vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size)
+{
+	return __vfs_getxattr(dentry, dentry->d_inode, name, value, size, 0);
 }
 EXPORT_SYMBOL_GPL(vfs_getxattr);
 
diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
index 3123b5aaad2a..cafc99c48e20 100644
--- a/fs/xfs/xfs_xattr.c
+++ b/fs/xfs/xfs_xattr.c
@@ -18,7 +18,8 @@
 
 static int
 xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused,
-		struct inode *inode, const char *name, void *value, size_t size)
+		struct inode *inode, const char *name, void *value, size_t size,
+		int flags)
 {
 	int xflags = handler->flags;
 	struct xfs_inode *ip = XFS_I(inode);
diff --git a/include/linux/xattr.h b/include/linux/xattr.h
index 6dad031be3c2..4df9dcdc48c5 100644
--- a/include/linux/xattr.h
+++ b/include/linux/xattr.h
@@ -30,10 +30,10 @@ struct xattr_handler {
 	const char *prefix;
 	int flags;      /* fs private flags */
 	bool (*list)(struct dentry *dentry);
-	int (*get)(const struct xattr_handler *, struct dentry *dentry,
+	int (*get)(const struct xattr_handler *handler, struct dentry *dentry,
 		   struct inode *inode, const char *name, void *buffer,
-		   size_t size);
-	int (*set)(const struct xattr_handler *, struct dentry *dentry,
+		   size_t size, int flags);
+	int (*set)(const struct xattr_handler *handler, struct dentry *dentry,
 		   struct inode *inode, const char *name, const void *buffer,
 		   size_t size, int flags);
 };
@@ -46,7 +46,8 @@ struct xattr {
 	size_t value_len;
 };
 
-ssize_t __vfs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t);
+ssize_t __vfs_getxattr(struct dentry *dentry, struct inode *inode,
+		       const char *name, void *buffer, size_t size, int flags);
 ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
 int __vfs_setxattr(struct dentry *, struct inode *, const char *, const void *, size_t, int);
diff --git a/include/uapi/linux/xattr.h b/include/uapi/linux/xattr.h
index c1395b5bd432..1216d777d210 100644
--- a/include/uapi/linux/xattr.h
+++ b/include/uapi/linux/xattr.h
@@ -17,8 +17,9 @@
 #if __UAPI_DEF_XATTR
 #define __USE_KERNEL_XATTR_DEFS
 
-#define XATTR_CREATE	0x1	/* set value, fail if attr already exists */
-#define XATTR_REPLACE	0x2	/* set value, fail if attr does not exist */
+#define XATTR_CREATE	 0x1	/* set value, fail if attr already exists */
+#define XATTR_REPLACE	 0x2	/* set value, fail if attr does not exist */
+#define XATTR_NOSECURITY 0x4	/* get value, do not involve security check */
 #endif
 
 /* Namespaces */
diff --git a/mm/shmem.c b/mm/shmem.c
index 626d8c74b973..34d3818b4424 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -3206,7 +3206,8 @@ static int shmem_initxattrs(struct inode *inode,
 
 static int shmem_xattr_handler_get(const struct xattr_handler *handler,
 				   struct dentry *unused, struct inode *inode,
-				   const char *name, void *buffer, size_t size)
+				   const char *name, void *buffer, size_t size,
+				   int flags)
 {
 	struct shmem_inode_info *info = SHMEM_I(inode);
 
diff --git a/net/socket.c b/net/socket.c
index 6a9ab7a8b1d2..6b0fea92dd02 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -300,7 +300,8 @@ static const struct dentry_operations sockfs_dentry_operations = {
 
 static int sockfs_xattr_get(const struct xattr_handler *handler,
 			    struct dentry *dentry, struct inode *inode,
-			    const char *suffix, void *value, size_t size)
+			    const char *suffix, void *value, size_t size,
+			    int flags)
 {
 	if (value) {
 		if (dentry->d_name.len + 1 > size)
diff --git a/security/commoncap.c b/security/commoncap.c
index f4ee0ae106b2..378a2f66a73d 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -297,7 +297,8 @@ int cap_inode_need_killpriv(struct dentry *dentry)
 	struct inode *inode = d_backing_inode(dentry);
 	int error;
 
-	error = __vfs_getxattr(dentry, inode, XATTR_NAME_CAPS, NULL, 0);
+	error = __vfs_getxattr(dentry, inode, XATTR_NAME_CAPS, NULL, 0,
+			       XATTR_NOSECURITY);
 	return error > 0;
 }
 
@@ -586,7 +587,8 @@ int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data
 
 	fs_ns = inode->i_sb->s_user_ns;
 	size = __vfs_getxattr((struct dentry *)dentry, inode,
-			      XATTR_NAME_CAPS, &data, XATTR_CAPS_SZ);
+			      XATTR_NAME_CAPS, &data, XATTR_CAPS_SZ,
+			      XATTR_NOSECURITY);
 	if (size == -ENODATA || size == -EOPNOTSUPP)
 		/* no data, that's ok */
 		return -ENODATA;
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index f9a81b187fae..921c8f2afcaf 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -100,7 +100,8 @@ static int evm_find_protected_xattrs(struct dentry *dentry)
 		return -EOPNOTSUPP;
 
 	list_for_each_entry_rcu(xattr, &evm_config_xattrnames, list) {
-		error = __vfs_getxattr(dentry, inode, xattr->name, NULL, 0);
+		error = __vfs_getxattr(dentry, inode, xattr->name, NULL, 0,
+				       XATTR_NOSECURITY);
 		if (error < 0) {
 			if (error == -ENODATA)
 				continue;
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 74dd46de01b6..b0822da0658f 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -552,7 +552,8 @@ static int sb_finish_set_opts(struct super_block *sb)
 			goto out;
 		}
 
-		rc = __vfs_getxattr(root, root_inode, XATTR_NAME_SELINUX, NULL, 0);
+		rc = __vfs_getxattr(root, root_inode, XATTR_NAME_SELINUX, NULL,
+				    0, XATTR_NOSECURITY);
 		if (rc < 0 && rc != -ENODATA) {
 			if (rc == -EOPNOTSUPP)
 				pr_warn("SELinux: (dev %s, type "
@@ -1378,12 +1379,14 @@ static int inode_doinit_use_xattr(struct inode *inode, struct dentry *dentry,
 		return -ENOMEM;
 
 	context[len] = '\0';
-	rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len);
+	rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len,
+			    XATTR_NOSECURITY);
 	if (rc == -ERANGE) {
 		kfree(context);
 
 		/* Need a larger buffer.  Query for the right size. */
-		rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, NULL, 0);
+		rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, NULL, 0,
+				    XATTR_NOSECURITY);
 		if (rc < 0)
 			return rc;
 
@@ -1394,7 +1397,7 @@ static int inode_doinit_use_xattr(struct inode *inode, struct dentry *dentry,
 
 		context[len] = '\0';
 		rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX,
-				    context, len);
+				    context, len, XATTR_NOSECURITY);
 	}
 	if (rc < 0) {
 		kfree(context);
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 4c5e5a438f8b..158b35772be1 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -292,7 +292,8 @@ static struct smack_known *smk_fetch(const char *name, struct inode *ip,
 	if (buffer == NULL)
 		return ERR_PTR(-ENOMEM);
 
-	rc = __vfs_getxattr(dp, ip, name, buffer, SMK_LONGLABEL);
+	rc = __vfs_getxattr(dp, ip, name, buffer, SMK_LONGLABEL,
+			    XATTR_NOSECURITY);
 	if (rc < 0)
 		skp = ERR_PTR(rc);
 	else if (rc == 0)
@@ -3442,7 +3443,7 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
 			} else {
 				rc = __vfs_getxattr(dp, inode,
 					XATTR_NAME_SMACKTRANSMUTE, trattr,
-					TRANS_TRUE_SIZE);
+					TRANS_TRUE_SIZE, XATTR_NOSECURITY);
 				if (rc >= 0 && strncmp(trattr, TRANS_TRUE,
 						       TRANS_TRUE_SIZE) != 0)
 					rc = -EINVAL;
-- 
2.23.0.rc1.153.gdeed80330f-goog



^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH] Add flags option to get xattr method paired to __vfs_getxattr
  2019-08-12 19:32 [PATCH] Add flags option to get xattr method paired to __vfs_getxattr Mark Salyzyn
@ 2019-08-13  8:28 ` kbuild test robot
  2019-08-13  8:48 ` Greg Kroah-Hartman
  1 sibling, 0 replies; 9+ messages in thread
From: kbuild test robot @ 2019-08-13  8:28 UTC (permalink / raw)
  To: Mark Salyzyn
  Cc: kbuild-all, linux-kernel, kernel-team, Mark Salyzyn,
	Stephen Smalley, linux-security-module, stable,
	Eric Van Hensbergen, Latchesar Ionkov, Dominique Martinet,
	David Howells, Chris Mason, Josef Bacik, David Sterba,
	Jeff Layton, Sage Weil, Ilya Dryomov, Steve French, Tyler Hicks,
	Jan Kara, Theodore Ts\'o, Andreas Dilger, Jaegeuk Kim,
	Chao Yu, Miklos Szeredi, Bob Peterson, Andreas Gruenbacher,
	David Woodhouse, Richard Weinberger, Dave Kleikamp,
	Greg Kroah-Hartman, Tejun Heo, Trond Myklebust, Anna Schumaker,
	Mark Fasheh, Joel Becker, Joseph Qi, Mike Marshall,
	Martin Brandenburg, Alexander Viro, Phillip Lougher,
	Darrick J. Wong, linux-xfs, Hugh Dickins, David S. Miller,
	Serge Hallyn, James Morris, Mimi Zohar, Paul Moore, Eric Paris,
	Casey Schaufler, Andrew Morton, Vyacheslav Dubeyko,
	Ernesto =?unknown-8bit?Q?A=2E_Fern=C3=A1ndez?=,
	Mathieu Malaterre, v9fs-developer, linux-afs, linux-btrfs,
	ceph-devel, linux-cifs, samba-technical, ecryptfs, linux-ext4,
	linux-f2fs-devel, linux-fsdevel, cluster-devel, linux-mtd,
	jfs-discussion, linux-nfs, ocfs2-devel, devel, linux-unionfs,
	reiserfs-devel, linux-mm, netdev, linux-integrity, selinux

[-- Attachment #1: Type: text/plain, Size: 4149 bytes --]

Hi Mark,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[cannot apply to v5.3-rc4]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Mark-Salyzyn/Add-flags-option-to-get-xattr-method-paired-to-__vfs_getxattr/20190813-124612
config: c6x-allyesconfig (attached as .config)
compiler: c6x-elf-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=c6x 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> fs/ubifs/xattr.c:699:9: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
     .get = xattr_get,
            ^~~~~~~~~
   fs/ubifs/xattr.c:699:9: note: (near initialization for 'ubifs_user_xattr_handler.get')
   fs/ubifs/xattr.c:705:9: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
     .get = xattr_get,
            ^~~~~~~~~
   fs/ubifs/xattr.c:705:9: note: (near initialization for 'ubifs_trusted_xattr_handler.get')
   fs/ubifs/xattr.c:712:9: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
     .get = xattr_get,
            ^~~~~~~~~
   fs/ubifs/xattr.c:712:9: note: (near initialization for 'ubifs_security_xattr_handler.get')
   cc1: some warnings being treated as errors
--
>> drivers/staging//erofs/xattr.c:492:9: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
     .get = erofs_xattr_generic_get,
            ^~~~~~~~~~~~~~~~~~~~~~~
   drivers/staging//erofs/xattr.c:492:9: note: (near initialization for 'erofs_xattr_user_handler.get')
   drivers/staging//erofs/xattr.c:499:9: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
     .get = erofs_xattr_generic_get,
            ^~~~~~~~~~~~~~~~~~~~~~~
   drivers/staging//erofs/xattr.c:499:9: note: (near initialization for 'erofs_xattr_trusted_handler.get')
   drivers/staging//erofs/xattr.c:506:9: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
     .get = erofs_xattr_generic_get,
            ^~~~~~~~~~~~~~~~~~~~~~~
   drivers/staging//erofs/xattr.c:506:9: note: (near initialization for 'erofs_xattr_security_handler.get')
   cc1: some warnings being treated as errors
--
>> fs//afs/xattr.c:156:12: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
     .get    = afs_xattr_get_acl,
               ^~~~~~~~~~~~~~~~~
   fs//afs/xattr.c:156:12: note: (near initialization for 'afs_xattr_afs_acl_handler.get')
   fs//afs/xattr.c:327:9: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
     .get = afs_xattr_get_yfs,
            ^~~~~~~~~~~~~~~~~
   fs//afs/xattr.c:327:9: note: (near initialization for 'afs_xattr_yfs_handler.get')
   cc1: some warnings being treated as errors

vim +699 fs/ubifs/xattr.c

2b88fc21cae91e Andreas Gruenbacher 2016-04-22  696  
dfaf8d2aeca482 Ben Dooks           2016-06-21  697  static const struct xattr_handler ubifs_user_xattr_handler = {
2b88fc21cae91e Andreas Gruenbacher 2016-04-22  698  	.prefix = XATTR_USER_PREFIX,
ade46c3a6029de Richard Weinberger  2016-09-19 @699  	.get = xattr_get,
ade46c3a6029de Richard Weinberger  2016-09-19  700  	.set = xattr_set,
2b88fc21cae91e Andreas Gruenbacher 2016-04-22  701  };
2b88fc21cae91e Andreas Gruenbacher 2016-04-22  702  

:::::: The code at line 699 was first introduced by commit
:::::: ade46c3a6029dea49dbc6c7734b0f6a78d3f104c ubifs: Export xattr get and set functions

:::::: TO: Richard Weinberger <richard@nod.at>
:::::: CC: Richard Weinberger <richard@nod.at>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 49672 bytes --]

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH] Add flags option to get xattr method paired to __vfs_getxattr
  2019-08-12 19:32 [PATCH] Add flags option to get xattr method paired to __vfs_getxattr Mark Salyzyn
  2019-08-13  8:28 ` kbuild test robot
@ 2019-08-13  8:48 ` Greg Kroah-Hartman
  2019-08-13 14:37   ` Mark Salyzyn
  2019-08-15 19:20   ` James Morris
  1 sibling, 2 replies; 9+ messages in thread
From: Greg Kroah-Hartman @ 2019-08-13  8:48 UTC (permalink / raw)
  To: Mark Salyzyn
  Cc: linux-kernel, kernel-team, Stephen Smalley,
	linux-security-module, stable, Eric Van Hensbergen,
	Latchesar Ionkov, Dominique Martinet, David Howells, Chris Mason,
	Josef Bacik, David Sterba, Jeff Layton, Sage Weil, Ilya Dryomov,
	Steve French, Tyler Hicks, Jan Kara, Theodore Ts\'o,
	Andreas Dilger, Jaegeuk Kim, Chao Yu, Miklos Szeredi,
	Bob Peterson, Andreas Gruenbacher, David Woodhouse,
	Richard Weinberger, Dave Kleikamp, Tejun Heo, Trond Myklebust,
	Anna Schumaker, Mark Fasheh, Joel Becker, Joseph Qi,
	Mike Marshall, Martin Brandenburg, Alexander Viro,
	Phillip Lougher, Darrick J. Wong, linux-xfs, Hugh Dickins,
	David S. Miller, Serge Hallyn, James Morris, Mimi Zohar,
	Paul Moore, Eric Paris, Casey Schaufler, Andrew Morton,
	Vyacheslav Dubeyko, Ernesto A. Fernández, Mathieu Malaterre,
	v9fs-developer, linux-afs, linux-btrfs, ceph-devel, linux-cifs,
	samba-technical, ecryptfs, linux-ext4, linux-f2fs-devel,
	linux-fsdevel, cluster-devel, linux-mtd, jfs-discussion,
	linux-nfs, ocfs2-devel, devel, linux-unionfs, reiserfs-devel,
	linux-mm, netdev, linux-integrity, selinux

On Mon, Aug 12, 2019 at 12:32:49PM -0700, Mark Salyzyn wrote:
> --- a/include/linux/xattr.h
> +++ b/include/linux/xattr.h
> @@ -30,10 +30,10 @@ struct xattr_handler {
>  	const char *prefix;
>  	int flags;      /* fs private flags */
>  	bool (*list)(struct dentry *dentry);
> -	int (*get)(const struct xattr_handler *, struct dentry *dentry,
> +	int (*get)(const struct xattr_handler *handler, struct dentry *dentry,
>  		   struct inode *inode, const char *name, void *buffer,
> -		   size_t size);
> -	int (*set)(const struct xattr_handler *, struct dentry *dentry,
> +		   size_t size, int flags);
> +	int (*set)(const struct xattr_handler *handler, struct dentry *dentry,
>  		   struct inode *inode, const char *name, const void *buffer,
>  		   size_t size, int flags);

Wow, 7 arguments.  Isn't there some nice rule of thumb that says once
you get more then 5, a function becomes impossible to understand?

Surely this could be a structure passed in here somehow, that way when
you add the 8th argument in the future, you don't have to change
everything yet again?  :)

I don't have anything concrete to offer as a replacement fix for this,
but to me this just feels really wrong...

thanks,

greg k-h


^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH] Add flags option to get xattr method paired to __vfs_getxattr
  2019-08-13  8:48 ` Greg Kroah-Hartman
@ 2019-08-13 14:37   ` Mark Salyzyn
  2019-08-15 19:20   ` James Morris
  1 sibling, 0 replies; 9+ messages in thread
From: Mark Salyzyn @ 2019-08-13 14:37 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: linux-kernel, kernel-team, Stephen Smalley,
	linux-security-module, stable, Eric Van Hensbergen,
	Latchesar Ionkov, Dominique Martinet, David Howells, Chris Mason,
	Josef Bacik, David Sterba, Jeff Layton, Sage Weil, Ilya Dryomov,
	Steve French, Tyler Hicks, Jan Kara, Theodore Ts\'o,
	Andreas Dilger, Jaegeuk Kim, Chao Yu, Miklos Szeredi,
	Bob Peterson, Andreas Gruenbacher, David Woodhouse,
	Richard Weinberger, Dave Kleikamp, Tejun Heo, Trond Myklebust,
	Anna Schumaker, Mark Fasheh, Joel Becker, Joseph Qi,
	Mike Marshall, Martin Brandenburg, Alexander Viro,
	Phillip Lougher, Darrick J. Wong, linux-xfs, Hugh Dickins,
	David S. Miller, Serge Hallyn, James Morris, Mimi Zohar,
	Paul Moore, Eric Paris, Casey Schaufler, Andrew Morton,
	Vyacheslav Dubeyko, Ernesto A. Fernández, Mathieu Malaterre,
	v9fs-developer, linux-afs, linux-btrfs, ceph-devel, linux-cifs,
	samba-technical, ecryptfs, linux-ext4, linux-f2fs-devel,
	linux-fsdevel, cluster-devel, linux-mtd, jfs-discussion,
	linux-nfs, ocfs2-devel, devel, linux-unionfs, reiserfs-devel,
	linux-mm, netdev, linux-integrity, selinux

On 8/13/19 1:48 AM, Greg Kroah-Hartman wrote:
> On Mon, Aug 12, 2019 at 12:32:49PM -0700, Mark Salyzyn wrote:
>> --- a/include/linux/xattr.h
>> +++ b/include/linux/xattr.h
>> @@ -30,10 +30,10 @@ struct xattr_handler {
>>   	const char *prefix;
>>   	int flags;      /* fs private flags */
>>   	bool (*list)(struct dentry *dentry);
>> -	int (*get)(const struct xattr_handler *, struct dentry *dentry,
>> +	int (*get)(const struct xattr_handler *handler, struct dentry *dentry,
>>   		   struct inode *inode, const char *name, void *buffer,
>> -		   size_t size);
>> -	int (*set)(const struct xattr_handler *, struct dentry *dentry,
>> +		   size_t size, int flags);
>> +	int (*set)(const struct xattr_handler *handler, struct dentry *dentry,
>>   		   struct inode *inode, const char *name, const void *buffer,
>>   		   size_t size, int flags);
> Wow, 7 arguments.  Isn't there some nice rule of thumb that says once
> you get more then 5, a function becomes impossible to understand?

This is a method with a pot-pourri of somewhat intuitive useful, but not 
always necessary, arguments, the additional argument does not complicate 
the function(s) AFAIK, but maybe its usage. Most functions do not even 
reference handler, the inode is typically a derivative of dentry, The 
arguments most used are the name of the attribute and the buffer/size 
the results are to be placed into.

The addition of flags is actually a pattern borrowed from the [.]set 
method, which provides at least 32 bits of 'control' (of which we added 
only one). Before, it was an anti-pattern.

> Surely this could be a structure passed in here somehow, that way when
> you add the 8th argument in the future, you don't have to change
> everything yet again?  :)
Just be happy I provided int flags, instead of bool no_security ;-> 
there are a few bits there that can be used in the future.
> I don't have anything concrete to offer as a replacement fix for this,
> but to me this just feels really wrong...

I went through 6 different alternatives (in the overlayfs security fix 
patch set) until I found this one that resonated with the security and 
filesystem stakeholders. The one was a direct result of trying to reduce 
the security attack surface. This code was created by threading a 
needle, and evolution. I am game for a 7th alternative to solve the 
unionfs set of recursive calls into acquiring the extended attributes.

-- Mark


^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH] Add flags option to get xattr method paired to __vfs_getxattr
  2019-08-13  8:48 ` Greg Kroah-Hartman
  2019-08-13 14:37   ` Mark Salyzyn
@ 2019-08-15 19:20   ` James Morris
  2019-08-15 20:43     ` Greg Kroah-Hartman
  2019-08-15 21:26     ` Mark Salyzyn
  1 sibling, 2 replies; 9+ messages in thread
From: James Morris @ 2019-08-15 19:20 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Mark Salyzyn, linux-kernel, kernel-team, Stephen Smalley,
	linux-security-module, stable, Eric Van Hensbergen,
	Latchesar Ionkov, Dominique Martinet, David Howells, Chris Mason,
	Josef Bacik, David Sterba, Jeff Layton, Sage Weil, Ilya Dryomov,
	Steve French, Tyler Hicks, Jan Kara, Theodore Ts\'o,
	Andreas Dilger, Jaegeuk Kim, Chao Yu, Miklos Szeredi,
	Bob Peterson, Andreas Gruenbacher, David Woodhouse,
	Richard Weinberger, Dave Kleikamp, Tejun Heo, Trond Myklebust,
	Anna Schumaker, Mark Fasheh, Joel Becker, Joseph Qi,
	Mike Marshall, Martin Brandenburg, Alexander Viro,
	Phillip Lougher, Darrick J. Wong, linux-xfs, Hugh Dickins,
	David S. Miller, Serge Hallyn, Mimi Zohar, Paul Moore,
	Eric Paris, Casey Schaufler, Andrew Morton, Vyacheslav Dubeyko,
	Ernesto A. Fernández, Mathieu Malaterre, v9fs-developer,
	linux-afs, linux-btrfs, ceph-devel, linux-cifs, samba-technical,
	ecryptfs, linux-ext4, linux-f2fs-devel, linux-fsdevel,
	cluster-devel, linux-mtd, jfs-discussion, linux-nfs, ocfs2-devel,
	devel, linux-unionfs, reiserfs-devel, linux-mm, netdev,
	linux-integrity, selinux

On Tue, 13 Aug 2019, Greg Kroah-Hartman wrote:

> On Mon, Aug 12, 2019 at 12:32:49PM -0700, Mark Salyzyn wrote:
> > --- a/include/linux/xattr.h
> > +++ b/include/linux/xattr.h
> > @@ -30,10 +30,10 @@ struct xattr_handler {
> >  	const char *prefix;
> >  	int flags;      /* fs private flags */
> >  	bool (*list)(struct dentry *dentry);
> > -	int (*get)(const struct xattr_handler *, struct dentry *dentry,
> > +	int (*get)(const struct xattr_handler *handler, struct dentry *dentry,
> >  		   struct inode *inode, const char *name, void *buffer,
> > -		   size_t size);
> > -	int (*set)(const struct xattr_handler *, struct dentry *dentry,
> > +		   size_t size, int flags);
> > +	int (*set)(const struct xattr_handler *handler, struct dentry *dentry,
> >  		   struct inode *inode, const char *name, const void *buffer,
> >  		   size_t size, int flags);
> 
> Wow, 7 arguments.  Isn't there some nice rule of thumb that says once
> you get more then 5, a function becomes impossible to understand?
> 
> Surely this could be a structure passed in here somehow, that way when
> you add the 8th argument in the future, you don't have to change
> everything yet again?  :)
> 
> I don't have anything concrete to offer as a replacement fix for this,
> but to me this just feels really wrong...

How about something like:

struct xattr_gs_args {
	struct dentry *dentry;
	struct inode *inode;
	const char *name;
	const void *buffer;
	size_t size;
	int flags;
};

int (*get)(const struct xattr_handler *handler, struct xattr_gs_args *args);
int (*set)(const struct xattr_handler *handler, struct xattr_gs_args *args);


-- 
James Morris
<jmorris@namei.org>



^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH] Add flags option to get xattr method paired to __vfs_getxattr
  2019-08-15 19:20   ` James Morris
@ 2019-08-15 20:43     ` Greg Kroah-Hartman
  2019-08-15 21:26     ` Mark Salyzyn
  1 sibling, 0 replies; 9+ messages in thread
From: Greg Kroah-Hartman @ 2019-08-15 20:43 UTC (permalink / raw)
  To: James Morris
  Cc: Mark Salyzyn, linux-kernel, kernel-team, Stephen Smalley,
	linux-security-module, stable, Eric Van Hensbergen,
	Latchesar Ionkov, Dominique Martinet, David Howells, Chris Mason,
	Josef Bacik, David Sterba, Jeff Layton, Sage Weil, Ilya Dryomov,
	Steve French, Tyler Hicks, Jan Kara, Theodore Ts\'o,
	Andreas Dilger, Jaegeuk Kim, Chao Yu, Miklos Szeredi,
	Bob Peterson, Andreas Gruenbacher, David Woodhouse,
	Richard Weinberger, Dave Kleikamp, Tejun Heo, Trond Myklebust,
	Anna Schumaker, Mark Fasheh, Joel Becker, Joseph Qi,
	Mike Marshall, Martin Brandenburg, Alexander Viro,
	Phillip Lougher, Darrick J. Wong, linux-xfs, Hugh Dickins,
	David S. Miller, Serge Hallyn, Mimi Zohar, Paul Moore,
	Eric Paris, Casey Schaufler, Andrew Morton, Vyacheslav Dubeyko,
	Ernesto A. Fernández, Mathieu Malaterre, v9fs-developer,
	linux-afs, linux-btrfs, ceph-devel, linux-cifs, samba-technical,
	ecryptfs, linux-ext4, linux-f2fs-devel, linux-fsdevel,
	cluster-devel, linux-mtd, jfs-discussion, linux-nfs, ocfs2-devel,
	devel, linux-unionfs, reiserfs-devel, linux-mm, netdev,
	linux-integrity, selinux

On Fri, Aug 16, 2019 at 05:20:36AM +1000, James Morris wrote:
> On Tue, 13 Aug 2019, Greg Kroah-Hartman wrote:
> 
> > On Mon, Aug 12, 2019 at 12:32:49PM -0700, Mark Salyzyn wrote:
> > > --- a/include/linux/xattr.h
> > > +++ b/include/linux/xattr.h
> > > @@ -30,10 +30,10 @@ struct xattr_handler {
> > >  	const char *prefix;
> > >  	int flags;      /* fs private flags */
> > >  	bool (*list)(struct dentry *dentry);
> > > -	int (*get)(const struct xattr_handler *, struct dentry *dentry,
> > > +	int (*get)(const struct xattr_handler *handler, struct dentry *dentry,
> > >  		   struct inode *inode, const char *name, void *buffer,
> > > -		   size_t size);
> > > -	int (*set)(const struct xattr_handler *, struct dentry *dentry,
> > > +		   size_t size, int flags);
> > > +	int (*set)(const struct xattr_handler *handler, struct dentry *dentry,
> > >  		   struct inode *inode, const char *name, const void *buffer,
> > >  		   size_t size, int flags);
> > 
> > Wow, 7 arguments.  Isn't there some nice rule of thumb that says once
> > you get more then 5, a function becomes impossible to understand?
> > 
> > Surely this could be a structure passed in here somehow, that way when
> > you add the 8th argument in the future, you don't have to change
> > everything yet again?  :)
> > 
> > I don't have anything concrete to offer as a replacement fix for this,
> > but to me this just feels really wrong...
> 
> How about something like:
> 
> struct xattr_gs_args {
> 	struct dentry *dentry;
> 	struct inode *inode;

As he said in a later message, dentry and inode is redundant, only 1 is
needed (dentry I think?)

> 	const char *name;
> 	const void *buffer;
> 	size_t size;
> 	int flags;
> };
> 
> int (*get)(const struct xattr_handler *handler, struct xattr_gs_args *args);
> int (*set)(const struct xattr_handler *handler, struct xattr_gs_args *args);

But yes, that would be much much better.

thanks,

greg k-h


^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH] Add flags option to get xattr method paired to __vfs_getxattr
  2019-08-15 19:20   ` James Morris
  2019-08-15 20:43     ` Greg Kroah-Hartman
@ 2019-08-15 21:26     ` Mark Salyzyn
  2019-08-15 22:27       ` James Morris
  1 sibling, 1 reply; 9+ messages in thread
From: Mark Salyzyn @ 2019-08-15 21:26 UTC (permalink / raw)
  To: James Morris, Greg Kroah-Hartman
  Cc: linux-kernel, kernel-team, Stephen Smalley,
	linux-security-module, stable, Eric Van Hensbergen,
	Latchesar Ionkov, Dominique Martinet, David Howells, Chris Mason,
	Josef Bacik, David Sterba, Jeff Layton, Sage Weil, Ilya Dryomov,
	Steve French, Tyler Hicks, Jan Kara, Theodore Ts\'o,
	Andreas Dilger, Jaegeuk Kim, Chao Yu, Miklos Szeredi,
	Bob Peterson, Andreas Gruenbacher, David Woodhouse,
	Richard Weinberger, Dave Kleikamp, Tejun Heo, Trond Myklebust,
	Anna Schumaker, Mark Fasheh, Joel Becker, Joseph Qi,
	Mike Marshall, Martin Brandenburg, Alexander Viro,
	Phillip Lougher, Darrick J. Wong, linux-xfs, Hugh Dickins,
	David S. Miller, Serge Hallyn, Mimi Zohar, Paul Moore,
	Eric Paris, Casey Schaufler, Andrew Morton, Vyacheslav Dubeyko,
	Ernesto A. Fernández, Mathieu Malaterre, v9fs-developer,
	linux-afs, linux-btrfs, ceph-devel, linux-cifs, samba-technical,
	ecryptfs, linux-ext4, linux-f2fs-devel, linux-fsdevel,
	cluster-devel, linux-mtd, jfs-discussion, linux-nfs, ocfs2-devel,
	devel, linux-unionfs, reiserfs-devel, linux-mm, netdev,
	linux-integrity, selinux

On 8/15/19 12:20 PM, James Morris wrote:
> On Tue, 13 Aug 2019, Greg Kroah-Hartman wrote:
>
>> On Mon, Aug 12, 2019 at 12:32:49PM -0700, Mark Salyzyn wrote:
>>> --- a/include/linux/xattr.h
>>> +++ b/include/linux/xattr.h
>>> @@ -30,10 +30,10 @@ struct xattr_handler {
>>>   	const char *prefix;
>>>   	int flags;      /* fs private flags */
>>>   	bool (*list)(struct dentry *dentry);
>>> -	int (*get)(const struct xattr_handler *, struct dentry *dentry,
>>> +	int (*get)(const struct xattr_handler *handler, struct dentry *dentry,
>>>   		   struct inode *inode, const char *name, void *buffer,
>>> -		   size_t size);
>>> -	int (*set)(const struct xattr_handler *, struct dentry *dentry,
>>> +		   size_t size, int flags);
>>> +	int (*set)(const struct xattr_handler *handler, struct dentry *dentry,
>>>   		   struct inode *inode, const char *name, const void *buffer,
>>>   		   size_t size, int flags);
>> Wow, 7 arguments.  Isn't there some nice rule of thumb that says once
>> you get more then 5, a function becomes impossible to understand?
>>
>> Surely this could be a structure passed in here somehow, that way when
>> you add the 8th argument in the future, you don't have to change
>> everything yet again?  :)
>>
>> I don't have anything concrete to offer as a replacement fix for this,
>> but to me this just feels really wrong...
> How about something like:
>
> struct xattr_gs_args {
> 	struct dentry *dentry;
> 	struct inode *inode;
> 	const char *name;
> 	const void *buffer;
> 	size_t size;
> 	int flags;
> };
>
> int (*get)(const struct xattr_handler *handler, struct xattr_gs_args *args);
> int (*set)(const struct xattr_handler *handler, struct xattr_gs_args *args);
>
Good Idea, but using the same argument structure for set and get I would 
be concerned about the loss of compiler protection for the buffer 
argument; it is void* for get, and const void* for set. And if we pulled 
out buffer (and size since it is paired with it) from the structure to 
solve, the 'mixed' argument approach (resulting in 4 args) adds to the 
difficulty/complexity.

Good news is the same structure(s) can get passed to __vfs_getxattr and 
__vfs_setxattr, so one less issue with getting the argument order 
correct from the caller.

 From an optimization standpoint, passing an argument to a pointer to a 
structure assembled on the stack constrains the compiler. Whereas 
individual arguments allow for the optimization to place all the 
arguments into registers. All modern processors have no issue with tens 
of arguments.

So, I will look into what the patch set will look like by splitting into 
set and get, and trying to reuse the structure down the call chain.

struct getxattr_args {
	struct dentry *dentry;
	struct inode *inode;
	const char *name;
	void *buffer;
	size_t size;
	int flags;
};

struct setxattr_args {
	struct dentry *dentry;
	struct inode *inode;
	const char *name;
	const void *buffer;
	size_t size;
	int flags;
};

-- Mark





^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH] Add flags option to get xattr method paired to __vfs_getxattr
  2019-08-15 21:26     ` Mark Salyzyn
@ 2019-08-15 22:27       ` James Morris
  2019-08-16 15:30         ` Mark Salyzyn
  0 siblings, 1 reply; 9+ messages in thread
From: James Morris @ 2019-08-15 22:27 UTC (permalink / raw)
  To: Mark Salyzyn
  Cc: Greg Kroah-Hartman, linux-kernel, kernel-team, Stephen Smalley,
	linux-security-module, stable, Eric Van Hensbergen,
	Latchesar Ionkov, Dominique Martinet, David Howells, Chris Mason,
	Josef Bacik, David Sterba, Jeff Layton, Sage Weil, Ilya Dryomov,
	Steve French, Tyler Hicks, Jan Kara, Theodore Ts\'o,
	Andreas Dilger, Jaegeuk Kim, Chao Yu, Miklos Szeredi,
	Bob Peterson, Andreas Gruenbacher, David Woodhouse,
	Richard Weinberger, Dave Kleikamp, Tejun Heo, Trond Myklebust,
	Anna Schumaker, Mark Fasheh, Joel Becker, Joseph Qi,
	Mike Marshall, Martin Brandenburg, Alexander Viro,
	Phillip Lougher, Darrick J. Wong, linux-xfs, Hugh Dickins,
	David S. Miller, Serge Hallyn, Mimi Zohar, Paul Moore,
	Eric Paris, Casey Schaufler, Andrew Morton, Vyacheslav Dubeyko,
	Ernesto A. Fernández, Mathieu Malaterre, v9fs-developer,
	linux-afs, linux-btrfs, ceph-devel, linux-cifs, samba-technical,
	ecryptfs, linux-ext4, linux-f2fs-devel, linux-fsdevel,
	cluster-devel, linux-mtd, jfs-discussion, linux-nfs, ocfs2-devel,
	devel, linux-unionfs, reiserfs-devel, linux-mm, netdev,
	linux-integrity, selinux

On Thu, 15 Aug 2019, Mark Salyzyn wrote:

> Good Idea, but using the same argument structure for set and get I would be
> concerned about the loss of compiler protection for the buffer argument;

Agreed, I missed that.

> struct getxattr_args {
> 	struct dentry *dentry;
> 	struct inode *inode;
> 	const char *name;
> 	void *buffer;
> 	size_t size;
> 	int flags;

Does 'get' need flags?

-- 
James Morris
<jmorris@namei.org>



^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH] Add flags option to get xattr method paired to __vfs_getxattr
  2019-08-15 22:27       ` James Morris
@ 2019-08-16 15:30         ` Mark Salyzyn
  0 siblings, 0 replies; 9+ messages in thread
From: Mark Salyzyn @ 2019-08-16 15:30 UTC (permalink / raw)
  To: James Morris
  Cc: Greg Kroah-Hartman, linux-kernel, kernel-team, Stephen Smalley,
	linux-security-module, stable, Eric Van Hensbergen,
	Latchesar Ionkov, Dominique Martinet, David Howells, Chris Mason,
	Josef Bacik, David Sterba, Jeff Layton, Sage Weil, Ilya Dryomov,
	Steve French, Tyler Hicks, Jan Kara, Theodore Ts\'o,
	Andreas Dilger, Jaegeuk Kim, Chao Yu, Miklos Szeredi,
	Bob Peterson, Andreas Gruenbacher, David Woodhouse,
	Richard Weinberger, Dave Kleikamp, Tejun Heo, Trond Myklebust,
	Anna Schumaker, Mark Fasheh, Joel Becker, Joseph Qi,
	Mike Marshall, Martin Brandenburg, Alexander Viro,
	Phillip Lougher, Darrick J. Wong, linux-xfs, Hugh Dickins,
	David S. Miller, Serge Hallyn, Mimi Zohar, Paul Moore,
	Eric Paris, Casey Schaufler, Andrew Morton, Vyacheslav Dubeyko,
	Ernesto A. Fernández, Mathieu Malaterre, v9fs-developer,
	linux-afs, linux-btrfs, ceph-devel, linux-cifs, samba-technical,
	ecryptfs, linux-ext4, linux-f2fs-devel, linux-fsdevel,
	cluster-devel, linux-mtd, jfs-discussion, linux-nfs, ocfs2-devel,
	devel, linux-unionfs, reiserfs-devel, linux-mm, netdev,
	linux-integrity, selinux

On 8/15/19 3:27 PM, James Morris wrote:
> On Thu, 15 Aug 2019, Mark Salyzyn wrote:
>
>> Good Idea, but using the same argument structure for set and get I would be
>> concerned about the loss of compiler protection for the buffer argument;
> Agreed, I missed that.

Sadly, the pattern of

struct getxattr_args args;

memset(&args, 0, sizeof(args));

args.xxxx = ...

__vfs_getxattr(&args};

...

__vfs_setxattr(&args);

would be nice, so maybe we need to cool our jets and instead:

struct xattr_gs_args {
	struct dentry *dentry;
	struct inode *inode;
	const char *name;
	union {
	        void *buffer;
	        const void *value;
	};
	size_t size;
	int flags;
};

value _must_ be referenced for all setxattr operations, buffer for getxattr operations (how can we enforce that?).

>> struct getxattr_args {
>> 	struct dentry *dentry;
>> 	struct inode *inode;
>> 	const char *name;
>> 	void *buffer;
>> 	size_t size;
>> 	int flags;
> Does 'get' need flags?
>
:-) That was the _whole_ point of the patch, flags is how we pass in the 
recursion so that a security/internal getxattr call has the rights to 
acquire the data in the lower layer(s).

-- Mark



^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, back to index

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-08-12 19:32 [PATCH] Add flags option to get xattr method paired to __vfs_getxattr Mark Salyzyn
2019-08-13  8:28 ` kbuild test robot
2019-08-13  8:48 ` Greg Kroah-Hartman
2019-08-13 14:37   ` Mark Salyzyn
2019-08-15 19:20   ` James Morris
2019-08-15 20:43     ` Greg Kroah-Hartman
2019-08-15 21:26     ` Mark Salyzyn
2019-08-15 22:27       ` James Morris
2019-08-16 15:30         ` Mark Salyzyn

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