From 6f5cf644bebc189bdb16f1caf3d7c47835d7c287 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Mon, 27 Jan 2020 19:01:36 +0100 Subject: [PATCH 065/116] virtiofsd: add --syslog command-line option MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Dr. David Alan Gilbert Message-id: <20200127190227.40942-62-dgilbert@redhat.com> Patchwork-id: 93509 O-Subject: [RHEL-AV-8.2 qemu-kvm PATCH 061/112] virtiofsd: add --syslog command-line option Bugzilla: 1694164 RH-Acked-by: Philippe Mathieu-Daudé RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Sergio Lopez Pascual From: Stefan Hajnoczi Sometimes collecting output from stderr is inconvenient or does not fit within the overall logging architecture. Add syslog(3) support for cases where stderr cannot be used. Signed-off-by: Stefan Hajnoczi dgilbert: Reworked as a logging function Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Daniel P. Berrangé Signed-off-by: Dr. David Alan Gilbert (cherry picked from commit f185621d41f03a23b55795b89e6584253fa23505) Signed-off-by: Miroslav Rezanina --- tools/virtiofsd/fuse_lowlevel.h | 1 + tools/virtiofsd/helper.c | 2 ++ tools/virtiofsd/passthrough_ll.c | 50 +++++++++++++++++++++++++++++++++++++--- tools/virtiofsd/seccomp.c | 32 +++++++++++++++++-------- tools/virtiofsd/seccomp.h | 4 +++- 5 files changed, 76 insertions(+), 13 deletions(-) diff --git a/tools/virtiofsd/fuse_lowlevel.h b/tools/virtiofsd/fuse_lowlevel.h index 0d61df8..f2750bc 100644 --- a/tools/virtiofsd/fuse_lowlevel.h +++ b/tools/virtiofsd/fuse_lowlevel.h @@ -1795,6 +1795,7 @@ struct fuse_cmdline_opts { int show_version; int show_help; int print_capabilities; + int syslog; unsigned int max_idle_threads; }; diff --git a/tools/virtiofsd/helper.c b/tools/virtiofsd/helper.c index 5531425..9692ef9 100644 --- a/tools/virtiofsd/helper.c +++ b/tools/virtiofsd/helper.c @@ -54,6 +54,7 @@ static const struct fuse_opt fuse_helper_opts[] = { FUSE_HELPER_OPT("subtype=", nodefault_subtype), FUSE_OPT_KEY("subtype=", FUSE_OPT_KEY_KEEP), FUSE_HELPER_OPT("max_idle_threads=%u", max_idle_threads), + FUSE_HELPER_OPT("--syslog", syslog), FUSE_OPT_END }; @@ -138,6 +139,7 @@ void fuse_cmdline_help(void) " -V --version print version\n" " --print-capabilities print vhost-user.json\n" " -d -o debug enable debug output (implies -f)\n" + " --syslog log to syslog (default stderr)\n" " -f foreground operation\n" " --daemonize run in background\n" " -o max_idle_threads the maximum number of idle worker " diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index c281d81..0372aca 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -58,6 +58,7 @@ #include #include #include +#include #include #include "passthrough_helpers.h" @@ -138,6 +139,7 @@ static const struct fuse_opt lo_opts[] = { { "norace", offsetof(struct lo_data, norace), 1 }, FUSE_OPT_END }; +static bool use_syslog = false; static void unref_inode(struct lo_data *lo, struct lo_inode *inode, uint64_t n); @@ -2262,11 +2264,12 @@ static void setup_mounts(const char *source) * Lock down this process to prevent access to other processes or files outside * source directory. This reduces the impact of arbitrary code execution bugs. */ -static void setup_sandbox(struct lo_data *lo, struct fuse_session *se) +static void setup_sandbox(struct lo_data *lo, struct fuse_session *se, + bool enable_syslog) { setup_namespaces(lo, se); setup_mounts(lo->source); - setup_seccomp(); + setup_seccomp(enable_syslog); } /* Raise the maximum number of open file descriptors */ @@ -2298,6 +2301,42 @@ static void setup_nofile_rlimit(void) } } +static void log_func(enum fuse_log_level level, const char *fmt, va_list ap) +{ + if (use_syslog) { + int priority = LOG_ERR; + switch (level) { + case FUSE_LOG_EMERG: + priority = LOG_EMERG; + break; + case FUSE_LOG_ALERT: + priority = LOG_ALERT; + break; + case FUSE_LOG_CRIT: + priority = LOG_CRIT; + break; + case FUSE_LOG_ERR: + priority = LOG_ERR; + break; + case FUSE_LOG_WARNING: + priority = LOG_WARNING; + break; + case FUSE_LOG_NOTICE: + priority = LOG_NOTICE; + break; + case FUSE_LOG_INFO: + priority = LOG_INFO; + break; + case FUSE_LOG_DEBUG: + priority = LOG_DEBUG; + break; + } + vsyslog(priority, fmt, ap); + } else { + vfprintf(stderr, fmt, ap); + } +} + int main(int argc, char *argv[]) { struct fuse_args args = FUSE_ARGS_INIT(argc, argv); @@ -2336,6 +2375,11 @@ int main(int argc, char *argv[]) if (fuse_parse_cmdline(&args, &opts) != 0) { return 1; } + fuse_set_log_func(log_func); + use_syslog = opts.syslog; + if (use_syslog) { + openlog("virtiofsd", LOG_PID, LOG_DAEMON); + } if (opts.show_help) { printf("usage: %s [options]\n\n", argv[0]); fuse_cmdline_help(); @@ -2424,7 +2468,7 @@ int main(int argc, char *argv[]) /* Must be before sandbox since it wants /proc */ setup_capng(); - setup_sandbox(&lo, se); + setup_sandbox(&lo, se, opts.syslog); /* Block until ctrl+c or fusermount -u */ ret = virtio_loop(se); diff --git a/tools/virtiofsd/seccomp.c b/tools/virtiofsd/seccomp.c index 691fb63..2d9d4a7 100644 --- a/tools/virtiofsd/seccomp.c +++ b/tools/virtiofsd/seccomp.c @@ -107,11 +107,28 @@ static const int syscall_whitelist[] = { SCMP_SYS(writev), }; -void setup_seccomp(void) +/* Syscalls used when --syslog is enabled */ +static const int syscall_whitelist_syslog[] = { + SCMP_SYS(sendto), +}; + +static void add_whitelist(scmp_filter_ctx ctx, const int syscalls[], size_t len) { - scmp_filter_ctx ctx; size_t i; + for (i = 0; i < len; i++) { + if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, syscalls[i], 0) != 0) { + fuse_log(FUSE_LOG_ERR, "seccomp_rule_add syscall %d failed\n", + syscalls[i]); + exit(1); + } + } +} + +void setup_seccomp(bool enable_syslog) +{ + scmp_filter_ctx ctx; + #ifdef SCMP_ACT_KILL_PROCESS ctx = seccomp_init(SCMP_ACT_KILL_PROCESS); /* Handle a newer libseccomp but an older kernel */ @@ -126,13 +143,10 @@ void setup_seccomp(void) exit(1); } - for (i = 0; i < G_N_ELEMENTS(syscall_whitelist); i++) { - if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, - syscall_whitelist[i], 0) != 0) { - fuse_log(FUSE_LOG_ERR, "seccomp_rule_add syscall %d", - syscall_whitelist[i]); - exit(1); - } + add_whitelist(ctx, syscall_whitelist, G_N_ELEMENTS(syscall_whitelist)); + if (enable_syslog) { + add_whitelist(ctx, syscall_whitelist_syslog, + G_N_ELEMENTS(syscall_whitelist_syslog)); } /* libvhost-user calls this for post-copy migration, we don't need it */ diff --git a/tools/virtiofsd/seccomp.h b/tools/virtiofsd/seccomp.h index 86bce72..d47c8ea 100644 --- a/tools/virtiofsd/seccomp.h +++ b/tools/virtiofsd/seccomp.h @@ -9,6 +9,8 @@ #ifndef VIRTIOFSD_SECCOMP_H #define VIRTIOFSD_SECCOMP_H -void setup_seccomp(void); +#include + +void setup_seccomp(bool enable_syslog); #endif /* VIRTIOFSD_SECCOMP_H */ -- 1.8.3.1