Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762387AbXKAXQb (ORCPT ); Thu, 1 Nov 2007 19:16:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754958AbXKAXJF (ORCPT ); Thu, 1 Nov 2007 19:09:05 -0400 Received: from e36.co.us.ibm.com ([32.97.110.154]:50256 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759216AbXKAXJA (ORCPT ); Thu, 1 Nov 2007 19:09:00 -0400 Subject: [PATCH 23/27] r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create To: akpm@osdl.org Cc: linux-kernel@vger.kernel.org, miklos@szeredi.hu, hch@infradead.org, Dave Hansen From: Dave Hansen Date: Thu, 01 Nov 2007 16:08:57 -0700 References: <20071101230826.9A4F6E00@kernel> In-Reply-To: <20071101230826.9A4F6E00@kernel> Message-Id: <20071101230857.626CA14E@kernel> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4289 Lines: 130 This takes care of all of the direct callers of vfs_mknod(). Since a few of these cases also handle normal file creation as well, this also covers some calls to vfs_create(). So that we don't have to make three mnt_want/drop_write() calls inside of the switch statement, we move some of its logic outside of the switch and into a helper function suggested by Christoph. This also encapsulates a fix for mknod(S_IFREG) that Miklos found. Acked-by: Christoph Hellwig Signed-off-by: Dave Hansen Signed-off-by: Andrew Morton --- linux-2.6.git-dave/fs/namei.c | 43 +++++++++++++++++++++++++--------- linux-2.6.git-dave/fs/nfsd/vfs.c | 4 +++ linux-2.6.git-dave/net/unix/af_unix.c | 4 +++ 3 files changed, 40 insertions(+), 11 deletions(-) diff -puN fs/namei.c~r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create fs/namei.c --- linux-2.6.git/fs/namei.c~r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create 2007-11-01 14:46:20.000000000 -0700 +++ linux-2.6.git-dave/fs/namei.c 2007-11-01 14:46:20.000000000 -0700 @@ -2022,6 +2022,23 @@ int vfs_mknod(struct inode *dir, struct return error; } +static int may_mknod(mode_t mode) +{ + switch (mode & S_IFMT) { + case S_IFREG: + case S_IFCHR: + case S_IFBLK: + case S_IFIFO: + case S_IFSOCK: + case 0: /* zero mode translates to S_IFREG */ + return 0; + case S_IFDIR: + return -EPERM; + default: + return -EINVAL; + } +} + asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode, unsigned dev) { @@ -2040,12 +2057,19 @@ asmlinkage long sys_mknodat(int dfd, con if (error) goto out; dentry = lookup_create(&nd, 0); - error = PTR_ERR(dentry); - + if (IS_ERR(dentry)) { + error = PTR_ERR(dentry); + goto out_unlock; + } if (!IS_POSIXACL(nd.dentry->d_inode)) mode &= ~current->fs->umask; - if (!IS_ERR(dentry)) { - switch (mode & S_IFMT) { + error = may_mknod(mode); + if (error) + goto out_dput; + error = mnt_want_write(nd.mnt); + if (error) + goto out_dput; + switch (mode & S_IFMT) { case 0: case S_IFREG: error = vfs_create(nd.dentry->d_inode,dentry,mode,&nd); break; @@ -2056,14 +2080,11 @@ asmlinkage long sys_mknodat(int dfd, con case S_IFIFO: case S_IFSOCK: error = vfs_mknod(nd.dentry->d_inode,dentry,mode,0); break; - case S_IFDIR: - error = -EPERM; - break; - default: - error = -EINVAL; - } - dput(dentry); } + mnt_drop_write(nd.mnt); +out_dput: + dput(dentry); +out_unlock: mutex_unlock(&nd.dentry->d_inode->i_mutex); path_release(&nd); out: diff -puN fs/nfsd/vfs.c~r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create fs/nfsd/vfs.c --- linux-2.6.git/fs/nfsd/vfs.c~r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create 2007-11-01 14:46:20.000000000 -0700 +++ linux-2.6.git-dave/fs/nfsd/vfs.c 2007-11-01 14:46:20.000000000 -0700 @@ -1242,7 +1242,11 @@ nfsd_create(struct svc_rqst *rqstp, stru case S_IFBLK: case S_IFIFO: case S_IFSOCK: + host_err = mnt_want_write(fhp->fh_export->ex_mnt); + if (host_err) + break; host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev); + mnt_drop_write(fhp->fh_export->ex_mnt); break; default: printk("nfsd: bad file type %o in nfsd_create\n", type); diff -puN net/unix/af_unix.c~r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create net/unix/af_unix.c --- linux-2.6.git/net/unix/af_unix.c~r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create 2007-11-01 14:46:20.000000000 -0700 +++ linux-2.6.git-dave/net/unix/af_unix.c 2007-11-01 14:46:20.000000000 -0700 @@ -838,7 +838,11 @@ static int unix_bind(struct socket *sock */ mode = S_IFSOCK | (SOCK_INODE(sock)->i_mode & ~current->fs->umask); + err = mnt_want_write(nd.mnt); + if (err) + goto out_mknod_dput; err = vfs_mknod(nd.dentry->d_inode, dentry, mode, 0); + mnt_drop_write(nd.mnt); if (err) goto out_mknod_dput; mutex_unlock(&nd.dentry->d_inode->i_mutex); _ - 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/