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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: agruen@kernel.org, bfields@fieldses.org,
	akpm@linux-foundation.org, dhowells@redhat.com
Cc: aneesh.kumar@linux.vnet.ibm.com, linux-fsdevel@vger.kernel.org,
	linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH -V6 08/26] vfs: Add new file and directory create permission flags
Date: Mon,  5 Sep 2011 22:55:30 +0530	[thread overview]
Message-ID: <1315243548-18664-9-git-send-email-aneesh.kumar@linux.vnet.ibm.com> (raw)
In-Reply-To: <1315243548-18664-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>

From: Andreas Gruenbacher <agruen@kernel.org>

Some permission models distinguish between the permission to create a
non-directory and a directory.  Pass this information down to
inode_permission() as mask flags

Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/namei.c         |   26 +++++++++++++++-----------
 include/linux/fs.h |    2 ++
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index a7a7ac0..d52a4cd 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -336,7 +336,8 @@ static inline int do_inode_permission(struct inode *inode, int mask)
  * for filesystem access without changing the "normal" uids which
  * are used for other things.
  *
- * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask.
+ * When checking for MAY_APPEND, MAY_CREATE_FILE, MAY_CREATE_DIR,
+ * MAY_WRITE must also be set in @mask.
  */
 int inode_permission(struct inode *inode, int mask)
 {
@@ -1923,13 +1924,15 @@ static int may_delete(struct inode *dir,struct dentry *victim,int isdir)
  *  3. We should have write and exec permissions on dir
  *  4. We can't do it if dir is immutable (done in permission())
  */
-static inline int may_create(struct inode *dir, struct dentry *child)
+static inline int may_create(struct inode *dir, struct dentry *child, int isdir)
 {
+	int mask = isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
+
 	if (child->d_inode)
 		return -EEXIST;
 	if (IS_DEADDIR(dir))
 		return -ENOENT;
-	return inode_permission(dir, MAY_WRITE | MAY_EXEC);
+	return inode_permission(dir, MAY_WRITE | MAY_EXEC | mask);
 }
 
 /*
@@ -1977,7 +1980,7 @@ void unlock_rename(struct dentry *p1, struct dentry *p2)
 int vfs_create(struct inode *dir, struct dentry *dentry, int mode,
 		struct nameidata *nd)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, 0);
 
 	if (error)
 		return error;
@@ -2436,7 +2439,7 @@ EXPORT_SYMBOL(user_path_create);
 
 int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, 0);
 
 	if (error)
 		return error;
@@ -2533,7 +2536,7 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, int, mode, unsigned, dev)
 
 int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, 1);
 
 	if (error)
 		return error;
@@ -2813,7 +2816,7 @@ SYSCALL_DEFINE1(unlink, const char __user *, pathname)
 
 int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, 0);
 
 	if (error)
 		return error;
@@ -2879,7 +2882,10 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
 	if (!inode)
 		return -ENOENT;
 
-	error = may_create(dir, new_dentry);
+	if (S_ISDIR(inode->i_mode))
+		return -EPERM;
+
+	error = may_create(dir, new_dentry, 0);
 	if (error)
 		return error;
 
@@ -2893,8 +2899,6 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
 		return -EPERM;
 	if (!dir->i_op->link)
 		return -EPERM;
-	if (S_ISDIR(inode->i_mode))
-		return -EPERM;
 
 	error = security_inode_link(old_dentry, dir, new_dentry);
 	if (error)
@@ -3102,7 +3106,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 		return error;
 
 	if (!new_dentry->d_inode)
-		error = may_create(new_dir, new_dentry);
+		error = may_create(new_dir, new_dentry, is_dir);
 	else
 		error = may_delete(new_dir, new_dentry, is_dir);
 	if (error)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1ddec24..8707f43 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -67,6 +67,8 @@ struct inodes_stat_t {
 #define MAY_CHDIR		0x00000040
 /* called from RCU mode, don't block */
 #define MAY_NOT_BLOCK		0x00000080
+#define MAY_CREATE_FILE		0x00000100
+#define MAY_CREATE_DIR		0x00000200
 
 /*
  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
-- 
1.7.4.1


  parent reply	other threads:[~2011-09-05 17:27 UTC|newest]

Thread overview: 79+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-05 17:25 [PATCH -V6 00/26] New ACL format for better NFSv4 acl interoperability Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 01/26] vfs: Indicate that the permission functions take all the MAY_* flags Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 02/26] vfs: Add hex format for MAY_* flag values Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 03/26] vfs: Pass all mask flags down to iop->check_acl Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 04/26] vfs: Add a comment to inode_permission() Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 05/26] vfs: Add generic IS_ACL() test for acl support Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 06/26] vfs: Add IS_RICHACL() test for richacl support Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 07/26] vfs: Optimize out IS_RICHACL() if CONFIG_FS_RICHACL is not defined Aneesh Kumar K.V
2011-09-05 17:25 ` Aneesh Kumar K.V [this message]
2011-09-05 17:25 ` [PATCH -V6 09/26] vfs: Add delete child and delete self permission flags Aneesh Kumar K.V
2011-09-07 20:39   ` J. Bruce Fields
2011-09-08  9:30     ` Aneesh Kumar K.V
2011-09-08 20:07       ` J. Bruce Fields
2011-09-08 22:02         ` J. Bruce Fields
2011-09-09  5:19           ` Aneesh Kumar K.V
2011-09-09  5:25             ` Aneesh Kumar K.V
2011-09-09 12:02               ` J. Bruce Fields
2011-09-09  5:14         ` Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 10/26] vfs: Make the inode passed to inode_change_ok non-const Aneesh Kumar K.V
2011-09-07 20:43   ` J. Bruce Fields
2011-09-08  9:32     ` Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 11/26] vfs: Add permission flags for setting file attributes Aneesh Kumar K.V
2011-09-07 20:55   ` J. Bruce Fields
2011-09-08  9:36     ` Aneesh Kumar K.V
2011-09-08 20:08       ` J. Bruce Fields
2011-09-05 17:25 ` [PATCH -V6 12/26] vfs: Make acl_permission_check() work for richacls Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 13/26] richacl: In-memory representation and helper functions Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 14/26] richacl: Permission mapping functions Aneesh Kumar K.V
2011-09-07 21:24   ` J. Bruce Fields
2011-09-08 10:27     ` Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 15/26] richacl: Compute maximum file masks from an acl Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 16/26] richacl: Update the file masks in chmod() Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 17/26] richacl: Permission check algorithm Aneesh Kumar K.V
2011-09-07 21:50   ` J. Bruce Fields
2011-09-08 10:34     ` Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 18/26] richacl: Create-time inheritance Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 19/26] richacl: Check if an acl is equivalent to a file mode Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 20/26] richacl: Automatic Inheritance Aneesh Kumar K.V
2011-09-07 21:56   ` J. Bruce Fields
2011-09-05 17:25 ` [PATCH -V6 21/26] richacl: xattr mapping functions Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 22/26] vfs: Cache richacl in struct inode Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 23/26] vfs: Add richacl permission check Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 24/26] ext4: Use IS_POSIXACL() to check for POSIX ACL support Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 25/26] ext4: Implement rich acl for ext4 Aneesh Kumar K.V
2011-09-05 17:25 ` [PATCH -V6 26/26] ext4: Add temporary richacl mount option " Aneesh Kumar K.V
2011-09-05 22:42 ` [PATCH -V6 00/26] New ACL format for better NFSv4 acl interoperability Casey Schaufler
2011-09-08  0:46   ` Valdis.Kletnieks
2011-09-12 21:34     ` Casey Schaufler
2011-09-12 22:20       ` J. Bruce Fields
2011-09-12 22:38         ` Casey Schaufler
2011-09-12 22:43           ` J. Bruce Fields
2011-09-12 23:23             ` Casey Schaufler
2011-09-12 23:53               ` J. Bruce Fields
2011-09-13  4:41           ` Aneesh Kumar K.V
2011-09-13 18:12       ` Valdis.Kletnieks
2011-09-06  9:41 ` Steven Whitehouse
2011-09-06 13:58   ` Aneesh Kumar K.V
2011-09-07 20:18     ` J. Bruce Fields
2011-09-07 23:44 ` J. Bruce Fields
2011-09-08 10:40   ` Aneesh Kumar K.V
2011-09-09 10:02 ` [PATCH -V6 08/26] vfs: Add new file and directory create permission flags David Howells
2011-09-09 11:59   ` Aneesh Kumar K.V
2011-09-09 10:12 ` [PATCH -V6 09/26] vfs: Add delete child and delete self " David Howells
2011-09-09 11:55   ` Aneesh Kumar K.V
2011-09-09 10:36 ` [PATCH -V6 14/26] richacl: Permission mapping functions David Howells
2011-09-09 11:54   ` Aneesh Kumar K.V
2011-09-09 12:14 ` [PATCH -V6 18/26] richacl: Create-time inheritance David Howells
2011-09-09 12:37 ` [PATCH -V6 22/26] vfs: Cache richacl in struct inode David Howells
2011-09-09 12:45 ` [PATCH -V6 25/26] ext4: Implement rich acl for ext4 David Howells
2011-09-13  4:25   ` Aneesh Kumar K.V
2011-09-09 12:48 ` [PATCH -V6 00/26] New ACL format for better NFSv4 acl interoperability David Howells
2011-09-09 14:03 ` David Howells
2011-09-12 22:23   ` J. Bruce Fields
2011-09-12 22:27   ` David Howells
2011-09-13  5:07     ` Aneesh Kumar K.V
2011-09-21  7:30 ` Aneesh Kumar K.V
2011-09-21 19:45   ` J. Bruce Fields
2011-09-22  5:31     ` Aneesh Kumar K.V
2011-09-22 12:01       ` J. Bruce Fields

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