From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Hansen Subject: [PATCH 12/23] elevate mount count for extended attributes Date: Wed, 11 Jul 2007 17:17:26 -0700 Message-ID: <20070712001726.13D005D1@kernel> References: <20070712001710.654CD9ED@kernel> Cc: linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, hch@infradead.org, Dave Hansen To: linux-kernel@vger.kernel.org Return-path: Received: from e34.co.us.ibm.com ([32.97.110.152]:33735 "EHLO e34.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S937463AbXGLAR3 (ORCPT ); Wed, 11 Jul 2007 20:17:29 -0400 In-Reply-To: <20070712001710.654CD9ED@kernel> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org This basically audits the callers of xattr_permission(), which calls permission() and can perform writes to the filesystem. Signed-off-by: Dave Hansen --- lxc-dave/fs/nfsd/nfs4proc.c | 7 ++++++- lxc-dave/fs/xattr.c | 16 ++++++++++++++-- 2 files changed, 20 insertions(+), 3 deletions(-) diff -puN fs/nfsd/nfs4proc.c~elevate-mount-count-for-extended-attributes fs/nfsd/nfs4proc.c --- lxc/fs/nfsd/nfs4proc.c~elevate-mount-count-for-extended-attributes 2007-07-10 12:46:10.000000000 -0700 +++ lxc-dave/fs/nfsd/nfs4proc.c 2007-07-10 12:46:10.000000000 -0700 @@ -626,14 +626,19 @@ 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~elevate-mount-count-for-extended-attributes fs/xattr.c --- lxc/fs/xattr.c~elevate-mount-count-for-extended-attributes 2007-07-10 12:46:10.000000000 -0700 +++ lxc-dave/fs/xattr.c 2007-07-10 12:46:10.000000000 -0700 @@ -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; } @@ -236,7 +235,11 @@ sys_setxattr(char __user *path, char __u error = user_path_walk(path, &nd); if (error) return error; + error = mnt_want_write(nd.mnt); + if (error) + return error; error = setxattr(nd.dentry, name, value, size, flags); + mnt_drop_write(nd.mnt); path_release(&nd); return error; } @@ -251,7 +254,11 @@ sys_lsetxattr(char __user *path, char __ error = user_path_walk_link(path, &nd); if (error) return error; + error = mnt_want_write(nd.mnt); + if (error) + return error; error = setxattr(nd.dentry, name, value, size, flags); + mnt_drop_write(nd.mnt); path_release(&nd); return error; } @@ -267,9 +274,14 @@ 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->d_inode); error = setxattr(dentry, name, value, size, flags); + mnt_drop_write(f->f_vfsmnt); +out_fput: fput(f); return error; } _