Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754013AbaD0QQs (ORCPT ); Sun, 27 Apr 2014 12:16:48 -0400 Received: from e23smtp03.au.ibm.com ([202.81.31.145]:35360 "EHLO e23smtp03.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753331AbaD0QPb (ORCPT ); Sun, 27 Apr 2014 12:15:31 -0400 From: "Aneesh Kumar K.V" To: agruen@kernel.org, bfields@fieldses.org, akpm@linux-foundation.org, viro@zeniv.linux.org.uk, 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 -V1 06/22] vfs: Add delete child and delete self permission flags Date: Sun, 27 Apr 2014 21:44:37 +0530 Message-Id: <1398615293-22931-7-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1398615293-22931-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1398615293-22931-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14042716-6102-0000-0000-00000573E602 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@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 | 45 ++++++++++++++++++++++++++++++++++----------- include/linux/fs.h | 2 ++ 2 files changed, 36 insertions(+), 11 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 028bc8bcf77c..56ac7613fbca 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -446,7 +446,7 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask) * changing the "normal" UIDs which 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) { @@ -2366,11 +2366,25 @@ kern_path_mountpoint(int dfd, const char *name, struct path *path, } EXPORT_SYMBOL(kern_path_mountpoint); + +/* + * We should have exec permission on directory and MAY_DELETE_SELF + * on the object being deleted. + */ +static int richacl_may_selfdelete(struct inode *dir, + struct inode *inode, int replace_mask) +{ + return (IS_RICHACL(inode) && + (inode_permission(dir, MAY_EXEC | replace_mask) == 0) && + (inode_permission(inode, MAY_DELETE_SELF) == 0)); +} + /* * It's inline, so penalty for filesystems that don't use sticky bit is * minimal. */ -static inline int check_sticky(struct inode *dir, struct inode *inode) +static inline int check_sticky(struct inode *dir, + struct inode *inode, int replace_mask) { kuid_t fsuid = current_fsuid(); @@ -2380,6 +2394,8 @@ static inline int check_sticky(struct inode *dir, struct inode *inode) return 0; if (uid_eq(dir->i_uid, fsuid)) return 0; + if (richacl_may_selfdelete(dir, inode, replace_mask)) + return 0; return !inode_capable(inode, CAP_FOWNER); } @@ -2402,10 +2418,11 @@ 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, bool isdir) +static int may_delete(struct inode *dir, struct dentry *victim, + bool isdir, bool replace) { struct inode *inode = victim->d_inode; - int error; + int error, mask, replace_mask = 0; if (d_is_negative(victim)) return -ENOENT; @@ -2414,13 +2431,19 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) BUG_ON(victim->d_parent->d_inode != dir); audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE); - error = inode_permission(dir, MAY_WRITE | MAY_EXEC); + mask = MAY_WRITE | MAY_EXEC | MAY_DELETE_CHILD; + if (replace) + replace_mask = S_ISDIR(inode->i_mode) ? + MAY_CREATE_DIR : MAY_CREATE_FILE; + error = inode_permission(dir, mask | replace_mask); + if (error && richacl_may_selfdelete(dir, inode, replace_mask)) + error = 0; if (error) return error; if (IS_APPEND(dir)) return -EPERM; - if (check_sticky(dir, inode) || IS_APPEND(inode) || + if (check_sticky(dir, inode, replace_mask) || IS_APPEND(inode) || IS_IMMUTABLE(inode) || IS_SWAPFILE(inode)) return -EPERM; if (isdir) { @@ -3539,7 +3562,7 @@ EXPORT_SYMBOL(dentry_unhash); 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; @@ -3658,7 +3681,7 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname) int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode) { struct inode *target = dentry->d_inode; - int error = may_delete(dir, dentry, 0); + int error = may_delete(dir, dentry, 0, 0); if (error) return error; @@ -4060,7 +4083,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, if (source == target) 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; @@ -4070,9 +4093,9 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, new_is_dir = d_is_dir(new_dentry); if (!(flags & RENAME_EXCHANGE)) - error = may_delete(new_dir, new_dentry, is_dir); + error = may_delete(new_dir, new_dentry, is_dir, 1); else - error = may_delete(new_dir, new_dentry, new_is_dir); + error = may_delete(new_dir, new_dentry, new_is_dir, 1); } if (error) return error; diff --git a/include/linux/fs.h b/include/linux/fs.h index da5521de04ab..3f0ad0f2bce8 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -79,6 +79,8 @@ typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset, #define MAY_NOT_BLOCK 0x00000080 #define MAY_CREATE_FILE 0x00000100 #define MAY_CREATE_DIR 0x00000200 +#define MAY_DELETE_CHILD 0x00000400 +#define MAY_DELETE_SELF 0x00000800 /* * flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/