diff options
| -rw-r--r-- | docs/tools/virtiofsd.rst | 5 | ||||
| -rw-r--r-- | tools/virtiofsd/helper.c | 2 | ||||
| -rw-r--r-- | tools/virtiofsd/passthrough_ll.c | 53 |
3 files changed, 58 insertions, 2 deletions
diff --git a/docs/tools/virtiofsd.rst b/docs/tools/virtiofsd.rst index 378594c422..824e713491 100644 --- a/docs/tools/virtiofsd.rst +++ b/docs/tools/virtiofsd.rst @@ -54,6 +54,11 @@ Options * flock|no_flock - Enable/disable flock. The default is ``no_flock``. + * modcaps=CAPLIST + Modify the list of capabilities allowed; CAPLIST is a colon separated + list of capabilities, each preceded by either + or -, e.g. + ''+sys_admin:-chown''. + * log_level=LEVEL - Print only log messages matching LEVEL or more severe. LEVEL is one of ``err``, ``warn``, ``info``, or ``debug``. The default is ``info``. diff --git a/tools/virtiofsd/helper.c b/tools/virtiofsd/helper.c index 00a1ef666a..3105b6c23a 100644 --- a/tools/virtiofsd/helper.c +++ b/tools/virtiofsd/helper.c @@ -174,6 +174,8 @@ void fuse_cmdline_help(void) " default: no_writeback\n" " -o xattr|no_xattr enable/disable xattr\n" " default: no_xattr\n" + " -o modcaps=CAPLIST Modify the list of capabilities\n" + " e.g. -o modcaps=+sys_admin:-chown\n" " --rlimit-nofile=<num> set maximum number of file descriptors\n" " (0 leaves rlimit unchanged)\n" " default: min(1000000, fs.file-max - 16384)\n" diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index 99d562046a..94e0de2d2b 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -145,6 +145,7 @@ struct lo_data { int posix_lock; int xattr; char *source; + char *modcaps; double timeout; int cache; int timeout_set; @@ -170,6 +171,7 @@ static const struct fuse_opt lo_opts[] = { { "no_posix_lock", offsetof(struct lo_data, posix_lock), 0 }, { "xattr", offsetof(struct lo_data, xattr), 1 }, { "no_xattr", offsetof(struct lo_data, xattr), 0 }, + { "modcaps=%s", offsetof(struct lo_data, modcaps), 0 }, { "timeout=%lf", offsetof(struct lo_data, timeout), 0 }, { "timeout=", offsetof(struct lo_data, timeout_set), 1 }, { "cache=none", offsetof(struct lo_data, cache), CACHE_NONE }, @@ -2570,9 +2572,11 @@ static void setup_mounts(const char *source) /* * Only keep whitelisted capabilities that are needed for file system operation + * The (possibly NULL) modcaps_in string passed in is free'd before exit. */ -static void setup_capabilities(void) +static void setup_capabilities(char *modcaps_in) { + char *modcaps = modcaps_in; pthread_mutex_lock(&cap.mutex); capng_restore_state(&cap.saved); @@ -2604,6 +2608,51 @@ static void setup_capabilities(void) exit(1); } + /* + * The modcaps option is a colon separated list of caps, + * each preceded by either + or -. + */ + while (modcaps) { + capng_act_t action; + int cap; + + char *next = strchr(modcaps, ':'); + if (next) { + *next = '\0'; + next++; + } + + switch (modcaps[0]) { + case '+': + action = CAPNG_ADD; + break; + + case '-': + action = CAPNG_DROP; + break; + + default: + fuse_log(FUSE_LOG_ERR, + "%s: Expecting '+'/'-' in modcaps but found '%c'\n", + __func__, modcaps[0]); + exit(1); + } + cap = capng_name_to_capability(modcaps + 1); + if (cap < 0) { + fuse_log(FUSE_LOG_ERR, "%s: Unknown capability '%s'\n", __func__, + modcaps); + exit(1); + } + if (capng_update(action, CAPNG_PERMITTED | CAPNG_EFFECTIVE, cap)) { + fuse_log(FUSE_LOG_ERR, "%s: capng_update failed for '%s'\n", + __func__, modcaps); + exit(1); + } + + modcaps = next; + } + g_free(modcaps_in); + if (capng_apply(CAPNG_SELECT_BOTH)) { fuse_log(FUSE_LOG_ERR, "%s: capng_apply failed\n", __func__); exit(1); @@ -2627,7 +2676,7 @@ static void setup_sandbox(struct lo_data *lo, struct fuse_session *se, setup_namespaces(lo, se); setup_mounts(lo->source); setup_seccomp(enable_syslog); - setup_capabilities(); + setup_capabilities(g_strdup(lo->modcaps)); } /* Set the maximum number of open file descriptors */ |