From: "Aneesh Kumar K.V" Subject: [PATCH -V5 07/24] vfs: Add new file and directory create permission flags Date: Wed, 23 Feb 2011 19:21:54 +0530 Message-ID: <1298469131-16555-8-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1298469131-16555-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Cc: aneesh.kumar@linux.vnet.ibm.com, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, Andreas Gruenbacher To: sfrench@us.ibm.com, agruen@linbit.com, dilger.kernel@dilger.ca, sandeen@redhat.com, tytso@mit.edu, bfields@fieldses.org, jlayton@redhat.com Return-path: In-Reply-To: <1298469131-16555-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org From: Andreas Gruenbacher 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 Signed-off-by: Aneesh Kumar K.V --- 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 b1e5104..b4f7198 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -252,7 +252,8 @@ int generic_permission(struct inode *inode, int mask, unsigned int flags, * 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) { @@ -2005,13 +2006,15 @@ 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); } /* @@ -2059,7 +2062,7 @@ 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; @@ -2629,7 +2632,7 @@ EXPORT_SYMBOL_GPL(lookup_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; @@ -2733,7 +2736,7 @@ 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; @@ -3016,7 +3019,7 @@ 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; @@ -3089,7 +3092,10 @@ 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; @@ -3103,8 +3109,6 @@ 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) @@ -3305,7 +3309,7 @@ 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 1dc6e72..a86afc0 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -62,6 +62,8 @@ struct inodes_stat_t { #define MAY_ACCESS 16 #define MAY_OPEN 32 #define MAY_CHDIR 64 +#define MAY_CREATE_FILE 128 +#define MAY_CREATE_DIR 256 /* * flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond -- 1.7.1