From patchwork Sat Jun 5 01:08:50 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: jvrao X-Patchwork-Id: 104367 Received: from lists.sourceforge.net (lists.sourceforge.net [216.34.181.88]) by demeter.kernel.org (8.14.3/8.14.3) with ESMTP id o5515ZjE028329 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sat, 5 Jun 2010 01:06:11 GMT Received: from localhost ([127.0.0.1] helo=sfs-ml-3.v29.ch3.sourceforge.com) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.69) (envelope-from ) id 1OKhpB-0007bR-Fb; Sat, 05 Jun 2010 01:05:21 +0000 Received: from sfi-mx-3.v28.ch3.sourceforge.com ([172.29.28.123] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.69) (envelope-from ) id 1OKhpA-0007bF-Mq for v9fs-developer@lists.sourceforge.net; Sat, 05 Jun 2010 01:05:20 +0000 X-ACL-Warn: Received: from e32.co.us.ibm.com ([32.97.110.150]) by sfi-mx-3.v28.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.69) id 1OKhp9-00054n-RJ for v9fs-developer@lists.sourceforge.net; Sat, 05 Jun 2010 01:05:20 +0000 Received: from d03relay03.boulder.ibm.com (d03relay03.boulder.ibm.com [9.17.195.228]) by e32.co.us.ibm.com (8.14.4/8.13.1) with ESMTP id o550vohD028895 for ; Fri, 4 Jun 2010 18:57:50 -0600 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay03.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o5515Eq8115694 for ; Fri, 4 Jun 2010 19:05:14 -0600 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id o5515D9v007928 for ; Fri, 4 Jun 2010 19:05:14 -0600 Received: from localhost.localdomain (elm9m80.beaverton.ibm.com [9.47.81.80]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id o55156BG007599; Fri, 4 Jun 2010 19:05:12 -0600 From: "Venkateswararao Jujjuri (JV)" To: qemu-devel@nongnu.org Date: Fri, 4 Jun 2010 18:08:50 -0700 Message-Id: <1275700132-22823-9-git-send-email-jvrao@linux.vnet.ibm.com> X-Mailer: git-send-email 1.6.0.6 In-Reply-To: <1275700132-22823-1-git-send-email-jvrao@linux.vnet.ibm.com> References: <1275700132-22823-1-git-send-email-jvrao@linux.vnet.ibm.com> X-Spam-Score: -0.2 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -0.2 AWL AWL: From: address is in the auto white-list X-Headers-End: 1OKhp9-00054n-RJ Cc: v9fs-developer@lists.sourceforge.net, aliguori@us.ibm.com Subject: [V9fs-developer] [PATCH-V5 08/10] virtio-9p: Security model for symlink and readlink X-BeenThere: v9fs-developer@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: v9fs-developer-bounces@lists.sourceforge.net X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]); Sat, 05 Jun 2010 01:06:11 +0000 (UTC) diff --git a/hw/file-op-9p.h b/hw/file-op-9p.h index 12223de..0808630 100644 --- a/hw/file-op-9p.h +++ b/hw/file-op-9p.h @@ -55,7 +55,7 @@ typedef struct FileOperations int (*mksock)(FsContext *, const char *); int (*utime)(FsContext *, const char *, const struct utimbuf *); int (*remove)(FsContext *, const char *); - int (*symlink)(FsContext *, const char *, const char *); + int (*symlink)(FsContext *, const char *, const char *, FsCred *); int (*link)(FsContext *, const char *, const char *); int (*setuid)(FsContext *, uid_t); int (*close)(FsContext *, int); diff --git a/hw/virtio-9p-local.c b/hw/virtio-9p-local.c index e0a5f58..fcc2250 100644 --- a/hw/virtio-9p-local.c +++ b/hw/virtio-9p-local.c @@ -107,10 +107,25 @@ static int local_post_create_passthrough(FsContext *fs_ctx, const char *path, return 0; } -static ssize_t local_readlink(FsContext *ctx, const char *path, - char *buf, size_t bufsz) +static ssize_t local_readlink(FsContext *fs_ctx, const char *path, + char *buf, size_t bufsz) { - return readlink(rpath(ctx, path), buf, bufsz); + ssize_t tsize = -1; + if (fs_ctx->fs_sm == SM_MAPPED) { + int fd; + fd = open(rpath(fs_ctx, path), O_RDONLY); + if (fd == -1) { + return -1; + } + do { + tsize = read(fd, (void *)buf, bufsz); + } while (tsize == -1 && errno == EINTR); + close(fd); + return tsize; + } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) { + tsize = readlink(rpath(fs_ctx, path), buf, bufsz); + } + return tsize; } static int local_close(FsContext *ctx, int fd) @@ -314,10 +329,58 @@ err_end: } -static int local_symlink(FsContext *ctx, const char *oldpath, - const char *newpath) +static int local_symlink(FsContext *fs_ctx, const char *oldpath, + const char *newpath, FsCred *credp) { - return symlink(oldpath, rpath(ctx, newpath)); + int err = -1; + int serrno = 0; + + /* Determine the security model */ + if (fs_ctx->fs_sm == SM_MAPPED) { + int fd; + ssize_t oldpath_size, write_size; + fd = open(rpath(fs_ctx, newpath), O_CREAT|O_EXCL|O_RDWR, + SM_LOCAL_MODE_BITS); + if (fd == -1) { + return fd; + } + /* Write the oldpath (target) to the file. */ + oldpath_size = strlen(oldpath) + 1; + do { + write_size = write(fd, (void *)oldpath, oldpath_size); + } while (write_size == -1 && errno == EINTR); + + if (write_size != oldpath_size) { + serrno = errno; + close(fd); + err = -1; + goto err_end; + } + close(fd); + /* Set cleint credentials in symlink's xattr */ + credp->fc_mode = credp->fc_mode|S_IFLNK; + err = local_set_xattr(rpath(fs_ctx, newpath), credp); + if (err == -1) { + serrno = errno; + goto err_end; + } + } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) { + err = symlink(oldpath, rpath(fs_ctx, newpath)); + if (err) { + return err; + } + err = local_post_create_passthrough(fs_ctx, newpath, credp); + if (err == -1) { + serrno = errno; + goto err_end; + } + } + return err; + +err_end: + remove(rpath(fs_ctx, newpath)); + errno = serrno; + return err; } static int local_link(FsContext *ctx, const char *oldpath, const char *newpath) diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c index 005f725..1a25e96 100644 --- a/hw/virtio-9p.c +++ b/hw/virtio-9p.c @@ -199,10 +199,15 @@ static int v9fs_do_open2(V9fsState *s, V9fsCreateState *vs) return s->ops->open2(&s->ctx, vs->fullname.data, flags, &cred); } -static int v9fs_do_symlink(V9fsState *s, V9fsString *oldpath, - V9fsString *newpath) +static int v9fs_do_symlink(V9fsState *s, V9fsCreateState *vs) { - return s->ops->symlink(&s->ctx, oldpath->data, newpath->data); + FsCred cred; + cred_init(&cred); + cred.fc_uid = vs->fidp->uid; + cred.fc_mode = vs->perm | 0777; + + return s->ops->symlink(&s->ctx, vs->extension.data, vs->fullname.data, + &cred); } static int v9fs_do_link(V9fsState *s, V9fsString *oldpath, V9fsString *newpath) @@ -1785,7 +1790,7 @@ static void v9fs_create_post_lstat(V9fsState *s, V9fsCreateState *vs, int err) err = v9fs_do_mkdir(s, vs); v9fs_create_post_mkdir(s, vs, err); } else if (vs->perm & P9_STAT_MODE_SYMLINK) { - err = v9fs_do_symlink(s, &vs->extension, &vs->fullname); + err = v9fs_do_symlink(s, vs); v9fs_create_post_perms(s, vs, err); } else if (vs->perm & P9_STAT_MODE_LINK) { int32_t nfid = atoi(vs->extension.data);