From: "Aneesh Kumar K.V" Subject: [PATCH -V5 08/24] vfs: Add delete child and delete self permission flags Date: Wed, 23 Feb 2011 19:21:55 +0530 Message-ID: <1298469131-16555-9-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 Normally, deleting a file requires write access to the parent directory. Some permission models use a different permission on the parent directory to indicate delete access. In addition, a process can have per-file delete access even without delete access on the parent directory. Introduce two new inode_permission() mask flags and use them in may_delete() Signed-off-by: Andreas Gruenbacher Signed-off-by: Aneesh Kumar K.V --- fs/namei.c | 40 ++++++++++++++++++++++++++-------------- include/linux/fs.h | 2 ++ 2 files changed, 28 insertions(+), 14 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index b4f7198..1b6dbc9 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -253,7 +253,7 @@ int generic_permission(struct inode *inode, int mask, unsigned int flags, * are used for other things. * * When checking for MAY_APPEND, MAY_CREATE_FILE, MAY_CREATE_DIR, - * MAY_WRITE must also be set in @mask. + * MAY_DELETE_CHILD, MAY_DELETE_SELF, MAY_WRITE must also be set in @mask. */ int inode_permission(struct inode *inode, int mask) { @@ -1944,7 +1944,7 @@ static inline int check_sticky(struct inode *dir, struct inode *inode) return 0; if (dir->i_uid == fsuid) return 0; - return !capable(CAP_FOWNER); + return 1; } /* @@ -1966,30 +1966,42 @@ static inline int check_sticky(struct inode *dir, struct inode *inode) * 10. We don't allow removal of NFS sillyrenamed files; it's handled by * nfs_async_unlink(). */ -static int may_delete(struct inode *dir,struct dentry *victim,int isdir) +static int may_delete(struct inode *dir, struct dentry *victim, + int isdir, int replace) { - int error; + int mask, error, is_sticky; + struct inode *inode = victim->d_inode; - if (!victim->d_inode) + if (!inode) return -ENOENT; BUG_ON(victim->d_parent->d_inode != dir); audit_inode_child(victim, dir); - error = inode_permission(dir, MAY_WRITE | MAY_EXEC); + mask = MAY_WRITE | MAY_EXEC | MAY_DELETE_CHILD; + if (replace) + mask |= S_ISDIR(inode->i_mode) ? + MAY_CREATE_DIR : MAY_CREATE_FILE; + is_sticky = check_sticky(dir, inode); + error = inode_permission(dir, mask); + if ((error || is_sticky) && IS_RICHACL(inode) && + !inode_permission(dir, mask & ~(MAY_WRITE | MAY_DELETE_CHILD)) && + !inode_permission(inode, MAY_DELETE_SELF)) + error = 0; + else if (!error && is_sticky && !capable(CAP_FOWNER)) + error = -EPERM; if (error) return error; if (IS_APPEND(dir)) return -EPERM; - if (check_sticky(dir, victim->d_inode)||IS_APPEND(victim->d_inode)|| - IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode)) + if (IS_APPEND(inode) || IS_IMMUTABLE(inode) || IS_SWAPFILE(inode)) return -EPERM; if (isdir) { - if (!S_ISDIR(victim->d_inode->i_mode)) + if (!S_ISDIR(inode->i_mode)) return -ENOTDIR; if (IS_ROOT(victim)) return -EBUSY; - } else if (S_ISDIR(victim->d_inode->i_mode)) + } else if (S_ISDIR(inode->i_mode)) return -EISDIR; if (IS_DEADDIR(dir)) return -ENOENT; @@ -2824,7 +2836,7 @@ void dentry_unhash(struct dentry *dentry) int vfs_rmdir(struct inode *dir, struct dentry *dentry) { - int error = may_delete(dir, dentry, 1); + int error = may_delete(dir, dentry, 1, 0); if (error) return error; @@ -2911,7 +2923,7 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname) int vfs_unlink(struct inode *dir, struct dentry *dentry) { - int error = may_delete(dir, dentry, 0); + int error = may_delete(dir, dentry, 0, 0); if (error) return error; @@ -3304,14 +3316,14 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, if (old_dentry->d_inode == new_dentry->d_inode) return 0; - error = may_delete(old_dir, old_dentry, is_dir); + error = may_delete(old_dir, old_dentry, is_dir, 0); if (error) return error; if (!new_dentry->d_inode) error = may_create(new_dir, new_dentry, is_dir); else - error = may_delete(new_dir, new_dentry, is_dir); + error = may_delete(new_dir, new_dentry, is_dir, 1); if (error) return error; diff --git a/include/linux/fs.h b/include/linux/fs.h index a86afc0..6a6e017 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -64,6 +64,8 @@ struct inodes_stat_t { #define MAY_CHDIR 64 #define MAY_CREATE_FILE 128 #define MAY_CREATE_DIR 256 +#define MAY_DELETE_CHILD 512 +#define MAY_DELETE_SELF 1024 /* * flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond -- 1.7.1