From 79f2eb5ca7817584c64d488984712af32b44b689 Mon Sep 17 00:00:00 2001 From: "M. Mohan Kumar" Date: Wed, 14 Dec 2011 13:58:47 +0530 Subject: [PATCH] hw/9pfs: Add support to use named socket for proxy FS Add option to use named socket for communicating between proxy helper and qemu proxy FS. Access to socket can be given by using command line options -u and -g. We can achive the same using a shell script over qemu and virtfs-proxy-helper using exec fd<>, and then passing that fd as argument to qemu and virtfs-proxy-helper. Also having a server like virtfs-proxy-helper listening on a pathname without any authentication is little bit scary. So we have to decide whether this patch is really needed. Signed-off-by: M. Mohan Kumar Signed-off-by: Aneesh Kumar K.V --- fsdev/file-op-9p.h | 2 + fsdev/virtfs-proxy-helper.c | 86 ++++++++++++++++++++++++++++++++++++++++-- fsdev/virtfs-proxy-helper.texi | 4 ++ hw/9pfs/virtio-9p-proxy.c | 52 +++++++++++++++++++++---- qemu-config.c | 7 ++++ qemu-options.hx | 15 ++++++-- vl.c | 6 ++- 7 files changed, 157 insertions(+), 15 deletions(-) diff --git a/fsdev/file-op-9p.h b/fsdev/file-op-9p.h index 7ef14afea3..1e96c8bed9 100644 --- a/fsdev/file-op-9p.h +++ b/fsdev/file-op-9p.h @@ -57,6 +57,8 @@ typedef struct extended_ops { */ #define V9FS_SM_NONE 0x00000010 #define V9FS_RDONLY 0x00000020 +#define V9FS_PROXY_SOCK_FD 0x00000040 +#define V9FS_PROXY_SOCK_NAME 0x00000080 #define V9FS_SEC_MASK 0x0000001C diff --git a/fsdev/virtfs-proxy-helper.c b/fsdev/virtfs-proxy-helper.c index 3beed25b29..baafee25b3 100644 --- a/fsdev/virtfs-proxy-helper.c +++ b/fsdev/virtfs-proxy-helper.c @@ -57,6 +57,9 @@ static struct option helper_opts[] = { {"fd", required_argument, NULL, 'f'}, {"path", required_argument, NULL, 'p'}, {"nodaemon", no_argument, NULL, 'n'}, + {"socket", required_argument, NULL, 's'}, + {"uid", required_argument, NULL, 'u'}, + {"gid", required_argument, NULL, 'g'}, }; static bool is_daemon; @@ -690,11 +693,61 @@ err_out: return ret; } +/* create unix domain socket and return the descriptor */ +static int proxy_socket(const char *path, uid_t uid, gid_t gid) +{ + int sock, client; + struct sockaddr_un proxy, qemu; + socklen_t size; + + /* requested socket already exists, refuse to start */ + if (!access(path, F_OK)) { + do_log(LOG_CRIT, "socket already exists\n"); + return -1; + } + + sock = socket(AF_UNIX, SOCK_STREAM, 0); + if (sock < 0) { + do_perror("socket"); + return -1; + } + + /* mask other part of mode bits */ + umask(7); + + proxy.sun_family = AF_UNIX; + strcpy(proxy.sun_path, path); + if (bind(sock, (struct sockaddr *)&proxy, + sizeof(struct sockaddr_un)) < 0) { + do_perror("bind"); + return -1; + } + if (chown(proxy.sun_path, uid, gid) < 0) { + do_perror("chown"); + return -1; + } + if (listen(sock, 1) < 0) { + do_perror("listen"); + return -1; + } + + client = accept(sock, (struct sockaddr *)&qemu, &size); + if (client < 0) { + do_perror("accept"); + return -1; + } + return client; +} + static void usage(char *prog) { fprintf(stderr, "usage: %s\n" " -p|--path 9p path to export\n" " {-f|--fd } socket file descriptor to be used\n" + " {-s|--socket socket file used for communication\n" + " \t-u|--uid -g|--gid } - uid:gid combination to give " + " access to this socket\n" + " \tNote: -s & -f can not be used together\n" " [-n|--nodaemon] Run as a normal program\n", basename(prog)); } @@ -935,16 +988,20 @@ int main(int argc, char **argv) { int sock; char *rpath = NULL; + char *sock_name = NULL; struct stat stbuf; int c, option_index; int retval; struct statfs st_fs; + uid_t own_u; + gid_t own_g; is_daemon = true; sock = -1; + own_u = own_g = -1; while (1) { option_index = 0; - c = getopt_long(argc, argv, "p:nh?f:", helper_opts, + c = getopt_long(argc, argv, "p:nh?f:s:u:g:", helper_opts, &option_index); if (c == -1) { break; @@ -959,6 +1016,15 @@ int main(int argc, char **argv) case 'f': sock = atoi(optarg); break; + case 's': + sock_name = strdup(optarg); + break; + case 'u': + own_u = atoi(optarg); + break; + case 'g': + own_g = atoi(optarg); + break; case '?': case 'h': default: @@ -968,8 +1034,16 @@ int main(int argc, char **argv) } /* Parameter validation */ - if (sock == -1 || rpath == NULL) { - fprintf(stderr, "socket descriptor or path not specified\n"); + if ((sock_name == NULL && sock == -1) || rpath == NULL) { + fprintf(stderr, "socket, socket descriptor or path not specified\n"); + usage(argv[0]); + return -1; + } + + if (*sock_name && (own_u == -1 || own_g == -1)) { + fprintf(stderr, "owner uid:gid not specified, "); + fprintf(stderr, + "owner uid:gid specifies who can access the socket file\n"); usage(argv[0]); exit(EXIT_FAILURE); } @@ -994,6 +1068,12 @@ int main(int argc, char **argv) } do_log(LOG_INFO, "Started\n"); + if (*sock_name) { + sock = proxy_socket(sock_name, own_u, own_g); + if (sock < 0) { + goto error; + } + } get_version = false; #ifdef FS_IOC_GETVERSION diff --git a/fsdev/virtfs-proxy-helper.texi b/fsdev/virtfs-proxy-helper.texi index 3816382bb9..faa0434480 100644 --- a/fsdev/virtfs-proxy-helper.texi +++ b/fsdev/virtfs-proxy-helper.texi @@ -46,6 +46,10 @@ Path to export for proxy filesystem driver Use given file descriptor as socket descriptor for communicating with qemu proxy fs drier. Usually a helper like libvirt will create socketpair and pass one of the fds as parameter to -f|--fd +@item -s|--socket socket-file +Creates named socket file for communicating with qemu proxy fs driver +@item -u|--uid uid -g|--gid gid +uid:gid combination to give access to named socket file @item -n|--nodaemon Run as a normal program. By default program will run in daemon mode @end table diff --git a/hw/9pfs/virtio-9p-proxy.c b/hw/9pfs/virtio-9p-proxy.c index e782c4fc13..d94db9519c 100644 --- a/hw/9pfs/virtio-9p-proxy.c +++ b/hw/9pfs/virtio-9p-proxy.c @@ -1095,15 +1095,49 @@ static int proxy_ioc_getversion(FsContext *fs_ctx, V9fsPath *path, return err; } +static int connect_namedsocket(const char *path) +{ + int sockfd, size; + struct sockaddr_un helper; + + sockfd = socket(AF_UNIX, SOCK_STREAM, 0); + if (sockfd < 0) { + fprintf(stderr, "socket %s\n", strerror(errno)); + return -1; + } + strcpy(helper.sun_path, path); + helper.sun_family = AF_UNIX; + size = strlen(helper.sun_path) + sizeof(helper.sun_family); + if (connect(sockfd, (struct sockaddr *)&helper, size) < 0) { + fprintf(stderr, "socket error\n"); + return -1; + } + + /* remove the socket for security reasons */ + unlink(path); + return sockfd; +} + static int proxy_parse_opts(QemuOpts *opts, struct FsDriverEntry *fs) { + const char *socket = qemu_opt_get(opts, "socket"); const char *sock_fd = qemu_opt_get(opts, "sock_fd"); - if (sock_fd) { - fprintf(stderr, "sock_fd option not specified\n"); + if (!socket && !sock_fd) { + fprintf(stderr, "socket and sock_fd none of the option specified\n"); + return -1; + } + if (socket && sock_fd) { + fprintf(stderr, "Both socket and sock_fd options specified\n"); return -1; } - fs->path = g_strdup(sock_fd); + if (socket) { + fs->path = g_strdup(socket); + fs->export_flags = V9FS_PROXY_SOCK_NAME; + } else { + fs->path = g_strdup(sock_fd); + fs->export_flags = V9FS_PROXY_SOCK_FD; + } return 0; } @@ -1112,10 +1146,14 @@ static int proxy_init(FsContext *ctx) V9fsProxy *proxy = g_malloc(sizeof(V9fsProxy)); int sock_id; - sock_id = atoi(ctx->fs_root); - if (sock_id < 0) { - fprintf(stderr, "socket descriptor not initialized\n"); - return -1; + if (ctx->export_flags & V9FS_PROXY_SOCK_NAME) { + sock_id = connect_namedsocket(ctx->fs_root); + } else { + sock_id = atoi(ctx->fs_root); + if (sock_id < 0) { + fprintf(stderr, "socket descriptor not initialized\n"); + return -1; + } } g_free(ctx->fs_root); diff --git a/qemu-config.c b/qemu-config.c index 1bdc01ca67..ecc88e8d40 100644 --- a/qemu-config.c +++ b/qemu-config.c @@ -211,6 +211,10 @@ QemuOptsList qemu_fsdev_opts = { }, { .name = "readonly", .type = QEMU_OPT_BOOL, + + }, { + .name = "socket", + .type = QEMU_OPT_STRING, }, { .name = "sock_fd", .type = QEMU_OPT_NUMBER, @@ -244,6 +248,9 @@ QemuOptsList qemu_virtfs_opts = { .name = "readonly", .type = QEMU_OPT_BOOL, }, { + .name = "socket", + .type = QEMU_OPT_STRING, + }, { .name = "sock_fd", .type = QEMU_OPT_NUMBER, }, diff --git a/qemu-options.hx b/qemu-options.hx index cfc999fe7c..85c24403f5 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -539,12 +539,12 @@ DEFHEADING(File system options:) DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, "-fsdev fsdriver,id=id[,path=path,][security_model={mapped|passthrough|none}]\n" - " [,writeout=immediate][,readonly][,sock_fd=sock_fd]\n", + " [,writeout=immediate][,readonly][,socket=socket|sock_fd=sock_fd]\n", QEMU_ARCH_ALL) STEXI -@item -fsdev @var{fsdriver},id=@var{id},path=@var{path},[security_model=@var{security_model}][,writeout=@var{writeout}][,readonly][,sock_fd=@var{sock_fd}] +@item -fsdev @var{fsdriver},id=@var{id},path=@var{path},[security_model=@var{security_model}][,writeout=@var{writeout}][,readonly][,socket=@var{socket}|sock_fd=@var{sock_fd}] @findex -fsdev Define a new file system device. Valid options are: @table @option @@ -577,6 +577,9 @@ reported as written by the storage subsystem. @item readonly Enables exporting 9p share as a readonly mount for guests. By default read-write access is given. +@item socket=@var{socket} +Enables proxy filesystem driver to use passed socket file for communicating +with virtfs-proxy-helper @item sock_fd=@var{sock_fd} Enables proxy filesystem driver to use passed socket descriptor for communicating with virtfs-proxy-helper. Usually a helper like libvirt @@ -601,12 +604,12 @@ DEFHEADING(Virtual File system pass-through options:) DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, "-virtfs local,path=path,mount_tag=tag,security_model=[mapped|passthrough|none]\n" - " [,writeout=immediate][,readonly][,sock_fd=sock_fd]\n", + " [,writeout=immediate][,readonly][,socket=socket|sock_fd=sock_fd]\n", QEMU_ARCH_ALL) STEXI -@item -virtfs @var{fsdriver}[,path=@var{path}],mount_tag=@var{mount_tag}[,security_model=@var{security_model}][,writeout=@var{writeout}][,readonly][,sock_fd=@var{sock_fd}] +@item -virtfs @var{fsdriver}[,path=@var{path}],mount_tag=@var{mount_tag}[,security_model=@var{security_model}][,writeout=@var{writeout}][,readonly][,socket=@var{socket}|sock_fd=@var{sock_fd}] @findex -virtfs The general form of a Virtual File system pass-through options are: @@ -640,6 +643,10 @@ reported as written by the storage subsystem. @item readonly Enables exporting 9p share as a readonly mount for guests. By default read-write access is given. +@item socket=@var{socket} +Enables proxy filesystem driver to use passed socket file for +communicating with virtfs-proxy-helper. Usually a helper like libvirt +will create socketpair and pass one of the fds as sock_fd @item sock_fd Enables proxy filesystem driver to use passed 'sock_fd' as the socket descriptor for interfacing with virtfs-proxy-helper diff --git a/vl.c b/vl.c index 6323361bc9..e553c2c907 100644 --- a/vl.c +++ b/vl.c @@ -2669,7 +2669,7 @@ int main(int argc, char **argv, char **envp) case QEMU_OPTION_virtfs: { QemuOpts *fsdev; QemuOpts *device; - const char *writeout, *sock_fd; + const char *writeout, *sock_fd, *socket; olist = qemu_find_opts("virtfs"); if (!olist) { @@ -2709,6 +2709,10 @@ int main(int argc, char **argv, char **envp) qemu_opt_set(fsdev, "path", qemu_opt_get(opts, "path")); qemu_opt_set(fsdev, "security_model", qemu_opt_get(opts, "security_model")); + socket = qemu_opt_get(opts, "socket"); + if (socket) { + qemu_opt_set(fsdev, "socket", socket); + } sock_fd = qemu_opt_get(opts, "sock_fd"); if (sock_fd) { qemu_opt_set(fsdev, "sock_fd", sock_fd); -- 2.11.4.GIT