Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933573AbYBOWo2 (ORCPT ); Fri, 15 Feb 2008 17:44:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761075AbYBOWht (ORCPT ); Fri, 15 Feb 2008 17:37:49 -0500 Received: from e2.ny.us.ibm.com ([32.97.182.142]:39292 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760183AbYBOWhm (ORCPT ); Fri, 15 Feb 2008 17:37:42 -0500 Subject: [PATCH 13/30] r/o bind mounts: elevate write count for xattr_permission() callers To: linux-kernel@vger.kernel.org Cc: hch@lst.de, miklos@szeredi.hu, akpm@osdl.org, Dave Hansen From: Dave Hansen Date: Fri, 15 Feb 2008 14:37:38 -0800 References: <20080215223721.9E0A088A@kernel> In-Reply-To: <20080215223721.9E0A088A@kernel> Message-Id: <20080215223738.F4FABDE9@kernel> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3390 Lines: 103 This basically audits the callers of xattr_permission(), which calls permission() and can perform writes to the filesystem. Acked-by: Al Viro Signed-off-by: Christoph Hellwig Signed-off-by: Dave Hansen Signed-off-by: Andrew Morton --- linux-2.6.git-dave/fs/nfsd/nfs4proc.c | 7 ++++++- linux-2.6.git-dave/fs/xattr.c | 16 ++++++++++++++-- 2 files changed, 20 insertions(+), 3 deletions(-) diff -puN fs/nfsd/nfs4proc.c~r-o-bind-mounts-elevate-mount-count-for-extended-attributes fs/nfsd/nfs4proc.c --- linux-2.6.git/fs/nfsd/nfs4proc.c~r-o-bind-mounts-elevate-mount-count-for-extended-attributes 2008-02-15 13:25:49.000000000 -0800 +++ linux-2.6.git-dave/fs/nfsd/nfs4proc.c 2008-02-15 13:25:49.000000000 -0800 @@ -658,14 +658,19 @@ nfsd4_setattr(struct svc_rqst *rqstp, st return status; } } + status = mnt_want_write(cstate->current_fh.fh_export->ex_mnt); + if (status) + return status; status = nfs_ok; if (setattr->sa_acl != NULL) status = nfsd4_set_nfs4_acl(rqstp, &cstate->current_fh, setattr->sa_acl); if (status) - return status; + goto out; status = nfsd_setattr(rqstp, &cstate->current_fh, &setattr->sa_iattr, 0, (time_t)0); +out: + mnt_drop_write(cstate->current_fh.fh_export->ex_mnt); return status; } diff -puN fs/xattr.c~r-o-bind-mounts-elevate-mount-count-for-extended-attributes fs/xattr.c --- linux-2.6.git/fs/xattr.c~r-o-bind-mounts-elevate-mount-count-for-extended-attributes 2008-02-15 13:25:49.000000000 -0800 +++ linux-2.6.git-dave/fs/xattr.c 2008-02-15 13:25:49.000000000 -0800 @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -32,8 +33,6 @@ xattr_permission(struct inode *inode, co * filesystem or on an immutable / append-only inode. */ if (mask & MAY_WRITE) { - if (IS_RDONLY(inode)) - return -EROFS; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) return -EPERM; } @@ -262,7 +261,11 @@ sys_setxattr(char __user *path, char __u error = user_path_walk(path, &nd); if (error) return error; + error = mnt_want_write(nd.path.mnt); + if (error) + return error; error = setxattr(nd.path.dentry, name, value, size, flags); + mnt_drop_write(nd.path.mnt); path_put(&nd.path); return error; } @@ -277,7 +280,11 @@ sys_lsetxattr(char __user *path, char __ error = user_path_walk_link(path, &nd); if (error) return error; + error = mnt_want_write(nd.path.mnt); + if (error) + return error; error = setxattr(nd.path.dentry, name, value, size, flags); + mnt_drop_write(nd.path.mnt); path_put(&nd.path); return error; } @@ -293,9 +300,14 @@ sys_fsetxattr(int fd, char __user *name, f = fget(fd); if (!f) return error; + error = mnt_want_write(f->f_vfsmnt); + if (error) + goto out_fput; dentry = f->f_path.dentry; audit_inode(NULL, dentry); error = setxattr(dentry, name, value, size, flags); + mnt_drop_write(f->f_vfsmnt); +out_fput: fput(f); return error; } _ -- 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/