From 4750a96f6baf8949cc04a0c5b7167606544a4401 Mon Sep 17 00:00:00 2001 From: "Venkateswararao Jujjuri (JV)" Date: Mon, 14 Jun 2010 13:34:45 -0700 Subject: virtio-9p: Security model for create/open2 In the mapped security model, VirtFS server intercepts and maps the file object create and get/set attribute requests. Files on the fileserver will be created with VirtFS servers (QEMU) user credentials and the client-users credentials are stored in extended attributes. On the request to get attributes, server extracts the client-users credentials from extended attributes and sends them to the client. On Host/Fileserver: -rw-------. 2 virfsuid virtfsgid 0 2010-05-11 09:19 afile On Guest/Client: -rw-r--r-- 2 guestuser guestuser 0 2010-05-11 12:19 afile Signed-off-by: Venkateswararao Jujjuri Signed-off-by: Anthony Liguori --- hw/virtio-9p-local.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 49 insertions(+), 2 deletions(-) (limited to 'hw/virtio-9p-local.c') diff --git a/hw/virtio-9p-local.c b/hw/virtio-9p-local.c index 74c81a60dc..bb5140efce 100644 --- a/hw/virtio-9p-local.c +++ b/hw/virtio-9p-local.c @@ -95,6 +95,18 @@ static int local_set_xattr(const char *path, FsCred *credp) return 0; } +static int local_post_create_passthrough(FsContext *fs_ctx, const char *path, + FsCred *credp) +{ + if (chmod(rpath(fs_ctx, path), credp->fc_mode & 07777) < 0) { + return -1; + } + if (chown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid) < 0) { + return -1; + } + return 0; +} + static ssize_t local_readlink(FsContext *ctx, const char *path, char *buf, size_t bufsz) { @@ -230,9 +242,44 @@ static int local_fstat(FsContext *fs_ctx, int fd, struct stat *stbuf) return err; } -static int local_open2(FsContext *ctx, const char *path, int flags, mode_t mode) +static int local_open2(FsContext *fs_ctx, const char *path, int flags, + FsCred *credp) { - return open(rpath(ctx, path), flags, mode); + int fd = -1; + int err = -1; + int serrno = 0; + + /* Determine the security model */ + if (fs_ctx->fs_sm == SM_MAPPED) { + fd = open(rpath(fs_ctx, path), flags, SM_LOCAL_MODE_BITS); + if (fd == -1) { + return fd; + } + credp->fc_mode = credp->fc_mode|S_IFREG; + /* Set cleint credentials in xattr */ + err = local_set_xattr(rpath(fs_ctx, path), credp); + if (err == -1) { + serrno = errno; + goto err_end; + } + } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) { + fd = open(rpath(fs_ctx, path), flags, credp->fc_mode); + if (fd == -1) { + return fd; + } + err = local_post_create_passthrough(fs_ctx, path, credp); + if (err == -1) { + serrno = errno; + goto err_end; + } + } + return fd; + +err_end: + close(fd); + remove(rpath(fs_ctx, path)); + errno = serrno; + return err; } -- cgit v1.2.3