From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48379) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dzm9x-0005Co-Mf for qemu-devel@nongnu.org; Wed, 04 Oct 2017 12:04:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dzm9r-0001ge-MU for qemu-devel@nongnu.org; Wed, 04 Oct 2017 12:04:33 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:31973) by eggs.gnu.org with esmtps (TLS1.0:RSA_ARCFOUR_SHA1:16) (Exim 4.71) (envelope-from ) id 1dzm9r-0001ds-Gq for qemu-devel@nongnu.org; Wed, 04 Oct 2017 12:04:27 -0400 From: Ian Jackson Date: Wed, 4 Oct 2017 16:53:11 +0100 Message-ID: <1507132392-25051-8-git-send-email-ian.jackson@eu.citrix.com> In-Reply-To: <1507132392-25051-1-git-send-email-ian.jackson@eu.citrix.com> References: <1507132392-25051-1-git-send-email-ian.jackson@eu.citrix.com> MIME-Version: 1.0 Content-Type: text/plain Subject: [Qemu-devel] [PATCH 7/8] os-posix: Provide new -runasid option List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Ross Lagerwall , =Anthony PERARD , xen-devel@nongnu.org, Juergen Gross , Stefano Stabellini , Ian Jackson , Ian Jackson This allows the caller to specify a uid and gid to use, even if there is no corresponding password entry. This will be useful in certain Xen configurations. Signed-off-by: Ian Jackson --- v2: Coding style fixes. --- os-posix.c | 31 +++++++++++++++++++++++++++---- qemu-options.hx | 12 ++++++++++++ 2 files changed, 39 insertions(+), 4 deletions(-) diff --git a/os-posix.c b/os-posix.c index 92e9d85..d63680b 100644 --- a/os-posix.c +++ b/os-posix.c @@ -43,6 +43,8 @@ #endif static struct passwd *user_pwd; +static uid_t user_uid = (uid_t)-1; +static gid_t user_gid = (gid_t)-1; static const char *chroot_dir; static int daemonize; static int daemon_pipe; @@ -134,6 +136,9 @@ void os_set_proc_name(const char *s) */ void os_parse_cmd_args(int index, const char *optarg) { + unsigned long lv; + char *ep; + int rc; switch (index) { #ifdef CONFIG_SLIRP case QEMU_OPTION_smb: @@ -150,6 +155,22 @@ void os_parse_cmd_args(int index, const char *optarg) exit(1); } break; + case QEMU_OPTION_runasid: + errno = 0; + lv = strtoul(optarg, &ep, 0); /* can't qemu_strtoul, want *ep=='.' */ + user_uid = lv; /* overflow here is ID in C99 */ + if (errno || *ep != '.' || user_uid != lv || user_uid == (uid_t)-1) { + fprintf(stderr, "Could not obtain uid from \"%s\"", optarg); + exit(1); + } + lv = 0; + rc = qemu_strtoul(ep + 1, 0, 0, &lv); + user_gid = lv; /* overflow here is ID in C99 */ + if (rc || user_gid != lv || user_gid == (gid_t)-1) { + fprintf(stderr, "Could not obtain gid from \"%s\"", optarg); + exit(1); + } + break; case QEMU_OPTION_chroot: chroot_dir = optarg; break; @@ -166,17 +187,19 @@ void os_parse_cmd_args(int index, const char *optarg) static void change_process_uid(void) { - if (user_pwd) { - if (setgid(user_pwd->pw_gid) < 0) { + if (user_pwd || user_uid != (uid_t)-1) { + if (setgid(user_pwd ? user_pwd->pw_gid : user_gid) < 0) { fprintf(stderr, "Failed to setgid(%d)\n", user_pwd->pw_gid); exit(1); } - if (initgroups(user_pwd->pw_name, user_pwd->pw_gid) < 0) { + if ((user_pwd + ? initgroups(user_pwd->pw_name, user_pwd->pw_gid) + : setgroups(1, &user_gid)) < 0) { fprintf(stderr, "Failed to initgroups(\"%s\", %d)\n", user_pwd->pw_name, user_pwd->pw_gid); exit(1); } - if (setuid(user_pwd->pw_uid) < 0) { + if (setuid(user_pwd ? user_pwd->pw_uid : user_gid) < 0) { fprintf(stderr, "Failed to setuid(%d)\n", user_pwd->pw_uid); exit(1); } diff --git a/qemu-options.hx b/qemu-options.hx index 9f6e2ad..34a5329 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -3968,6 +3968,18 @@ Immediately before starting guest execution, drop root privileges, switching to the specified user. ETEXI +#ifndef _WIN32 +DEF("runasid", HAS_ARG, QEMU_OPTION_runasid, \ + "-runasid uid.gid change to numeric uid and gid just before starting the VM\n", + QEMU_ARCH_ALL) +#endif +STEXI +@item -runasid @var{uid}.@var{gid} +@findex -runasid +Immediately before starting guest execution, drop root privileges, switching +to the specified uid and gid. +ETEXI + DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, "-prom-env variable=value\n" " set OpenBIOS nvram variables\n", -- 2.1.4