From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263188AbVGODMS (ORCPT ); Thu, 14 Jul 2005 23:12:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263189AbVGODKW (ORCPT ); Thu, 14 Jul 2005 23:10:22 -0400 Received: from wproxy.gmail.com ([64.233.184.199]:29812 "EHLO wproxy.gmail.com") by vger.kernel.org with ESMTP id S263185AbVGODKK (ORCPT ); Thu, 14 Jul 2005 23:10:10 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:date:from:to:cc:subject:message-id:references:mime-version:content-type:content-disposition:in-reply-to:user-agent; b=J7xWFTrio/JB/CiE6MXhBnO4bNnnS96S+A9vbxH1PtMRKvGN09vg/wq5qpgmZPGvmm3FcRiTStm9+RRb9g0ETmQ3cSIsVW7JiH2oJ50mkF64B5X3OCZzTOyP+yh4tPvGj9HjlTSrnULOpKEJU9ztt0VDKSocWmGuI0LMDFHg30Y= Date: Sat, 16 Jul 2005 15:23:28 +0100 From: Nicholas Hans Simmonds To: Horst von Brand Cc: Nathan Scott , linux-kernel@vger.kernel.org, "Andrew G. Morgan" , Alexey Dobriyan Subject: Re: [PATCH] Filesystem capabilities support Message-ID: <20050716142328.GA9125@laptop> References: <20050714042934.GA25447@laptop> <200507142005.j6EK5Hhn030304@laptop11.inf.utfsm.cl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200507142005.j6EK5Hhn030304@laptop11.inf.utfsm.cl> User-Agent: Mutt/1.5.8i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 14, 2005 at 04:05:17PM -0400, Horst von Brand wrote: > Nicholas Hans Simmonds wrote: > > [...] > > > Other than this, what are the general thoughts about this method as > > opposed to just using a well defined byte order? > > I'd prefer a defined byte order. That way it won't bite too hard if I > happen to move a filesystem (image) from PC to SPARC or whatever. > -- > Dr. Horst H. von Brand User #22616 counter.li.org > Departamento de Informatica Fono: +56 32 654431 > Universidad Tecnica Federico Santa Maria +56 32 654239 > Casilla 110-V, Valparaiso, Chile Fax: +56 32 797513 Fair enough. With inotify now in Linus' tree, my patch will conflict so I've fixed this in the following new patch which also stores the xattr data in big-endian format. I've tested it this time and it seems to work. Also if anyone can think of a neater method of byte- swapping the structure (some sort of string operation?) I'd be glad to hear it as the current code looks a bit ugly. Thanks as ever, Nicholas diff --git a/fs/read_write.c b/fs/read_write.c --- a/fs/read_write.c +++ b/fs/read_write.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include @@ -303,6 +304,16 @@ ssize_t vfs_write(struct file *file, con else ret = do_sync_write(file, buf, count, pos); if (ret > 0) { +#ifdef CONFIG_SECURITY_FS_CAPABILITIES + struct dentry *d = file->f_dentry; + if(d->d_inode->i_op && d->d_inode->i_op-> + removexattr) { + down(&d->d_inode->i_sem); + d->d_inode->i_op->removexattr(d, + XATTR_CAP_SET); + up(&d->d_inode->i_sem); + } +#endif /* CONFIG_SECURITY_FS_CAPABILITIES */ fsnotify_modify(file->f_dentry); current->wchar += ret; } diff --git a/include/linux/capability.h b/include/linux/capability.h --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -39,7 +39,19 @@ typedef struct __user_cap_data_struct { __u32 permitted; __u32 inheritable; } __user *cap_user_data_t; - + +struct cap_xattr_data { + __u32 version; + __u32 mask_effective; + __u32 effective; + __u32 mask_permitted; + __u32 permitted; + __u32 mask_inheritable; + __u32 inheritable; +}; + +#define XATTR_CAP_SET XATTR_SECURITY_PREFIX "cap_set" + #ifdef __KERNEL__ #include diff --git a/security/Kconfig b/security/Kconfig --- a/security/Kconfig +++ b/security/Kconfig @@ -60,6 +60,13 @@ config SECURITY_CAPABILITIES This enables the "default" Linux capabilities functionality. If you are unsure how to answer this question, answer Y. +config SECURITY_FS_CAPABILITIES + bool "Filesystem Capabilities (EXPERIMENTAL)" + depends on SECURITY && EXPERIMENTAL + help + This permits a process' capabilities to be set by an extended + attribute in the security namespace (security.cap_set). + config SECURITY_ROOTPLUG tristate "Root Plug Support" depends on USB && SECURITY diff --git a/security/commoncap.c b/security/commoncap.c --- a/security/commoncap.c +++ b/security/commoncap.c @@ -111,9 +111,15 @@ void cap_capset_set (struct task_struct int cap_bprm_set_security (struct linux_binprm *bprm) { +#ifdef CONFIG_SECURITY_FS_CAPABILITIES + ssize_t (*bprm_getxattr)(struct dentry *,const char *,void *,size_t); + struct dentry *bprm_dentry; + ssize_t ret; + struct cap_xattr_data caps; +#endif /* CONFIG_SECURITY_FS_CAPABILITIES */ + /* Copied from fs/exec.c:prepare_binprm. */ - /* We don't have VFS support for capabilities yet */ cap_clear (bprm->cap_inheritable); cap_clear (bprm->cap_permitted); cap_clear (bprm->cap_effective); @@ -134,6 +140,44 @@ int cap_bprm_set_security (struct linux_ if (bprm->e_uid == 0) cap_set_full (bprm->cap_effective); } + +#ifdef CONFIG_SECURITY_FS_CAPABILITIES + /* Locate any VFS capabilities: */ + + bprm_dentry = bprm->file->f_dentry; + if(!(bprm_dentry->d_inode->i_op && + bprm_dentry->d_inode->i_op->getxattr)) + return 0; + bprm_getxattr = bprm_dentry->d_inode->i_op->getxattr; + + down(&bprm_dentry->d_inode->i_sem); + ret = bprm_getxattr(bprm_dentry,XATTR_CAP_SET,&caps,sizeof(caps)); + up(&bprm_dentry->d_inode->i_sem); + if(ret == sizeof(caps)) { + be32_to_cpus(&caps.version); + be32_to_cpus(&caps.effective); + be32_to_cpus(&caps.mask_effective); + be32_to_cpus(&caps.permitted); + be32_to_cpus(&caps.mask_permitted); + be32_to_cpus(&caps.inheritable); + be32_to_cpus(&caps.mask_inheritable); + if(caps.version == _LINUX_CAPABILITY_VERSION) { + cap_t(bprm->cap_effective) &= caps.mask_effective; + cap_t(bprm->cap_effective) |= caps.effective; + + cap_t(bprm->cap_permitted) &= caps.mask_permitted; + cap_t(bprm->cap_permitted) |= caps.permitted; + + cap_t(bprm->cap_inheritable) &= caps.mask_inheritable; + cap_t(bprm->cap_inheritable) |= caps.inheritable; + } else + printk(KERN_WARNING "Warning: %s capability set has " + "incorrect version %08X. Correct version " + "is %08X.\n",bprm->filename,caps.version, + _LINUX_CAPABILITY_VERSION); + } +#endif /* CONFIG_SECURITY_FS_CAPABILITIES */ + return 0; }