X-Git-Url: http://git.linux-vserver.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Frpm-fake.c;fp=src%2Frpm-fake.c;h=2c1310639fca46623a44620571a6fc0a1646ed94;hb=9c78378bebc1a9f3d400f422df8ede9efea57dea;hp=0000000000000000000000000000000000000000;hpb=faa778968d1a7dfeaebc9fe4b847e691dc62fd15;p=util-vserver.git diff --git a/src/rpm-fake.c b/src/rpm-fake.c new file mode 100644 index 0000000..2c13106 --- /dev/null +++ b/src/rpm-fake.c @@ -0,0 +1,726 @@ +// $Id$ --*- c++ -*-- + +// Copyright (C) 2003 Enrico Scholz +// +// This program is free software; you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation; version 2 of the License. +// +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this program; if not, write to the Free Software +// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. +// + +#ifdef HAVE_CONFIG_H +# include +#endif + +#include "pathconfig.h" +#include "util.h" + +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + + + // from selinux.h + // FIXME: add configure autodetection and include directly +int rpm_execcon(unsigned int verified, + const char *filename, + char *const argv[], char *const envp[]); + + +#define ENSC_WRAPPERS_PREFIX "rpm-fake.so: " +#define ENSC_WRAPPERS_VSERVER 1 +#define ENSC_WRAPPERS_UNISTD 1 +#include + +#undef _POSIX_SOURCE +#include "capability-compat.h" + +#ifndef CLONE_NEWNS +# define CLONE_NEWNS 0x00020000 +#endif + +#define LIBNAME "rpm-fake.so" +#define PLATFORM_FILE "/etc/rpm/platform" + +#define INIT(FILE,FUNC) FUNC##_func = ((__typeof__(FUNC) *) (xdlsym(FILE, #FUNC))) +#define DECLARE(FUNC) static __typeof__(FUNC) * FUNC##_func = 0 + +#define DEBUG 1 + +#define DBG_INIT 0x0001 +#define DBG_VARIABLES 0x0002 +#define DBG_RESOLVER 0x0004 +#define DBG_EXECV 0x0008 +#define DBG_ENV 0x0010 +#define DBG_VERBOSE0 0x8000 +#define DBG_VERBOSE1 (0x4000 | DBG_VERBOSE0) +#define DBG_VERBOSE2 (0x2000 | DBG_VERBOSE1) + +int wrapper_exit_code = 255; + +static xid_t ctx = VC_NOCTX; +static uint32_t caps = ~0; +static int flags = 0; +static char const * mnts = 0; +static char const * root = 0; +static int pw_sock = -1; +static int sync_sock = -1; +static unsigned int debug_level = 0; + +static bool is_initialized = false; + + //DECLARE(rpm_execcon); + //DECLARE(execv); +DECLARE(getpwnam); +DECLARE(getgrnam); +DECLARE(endpwent); +DECLARE(endgrent); + +static void initRPMFake() __attribute__((__constructor__)); +static void exitRPMFake() __attribute__((__destructor__)); + +static inline bool +isDbgLevel(unsigned int level) +{ + return ((debug_level&level)==level); +} + +static void * +xdlsym(void *handle, const char *symbol) +{ + void *res = dlsym(handle, symbol); + if (res==0) { + char const *error = dlerror(); + Vwrite(2, symbol, strlen(symbol)); + Vwrite(2, ": ", 2); + Vwrite(2, error, strlen(error)); + Vwrite(2, "\n", 2); + + _exit(255); + } + + return res; +} + +static void +showHelp() +{ + WRITE_MSG(1, + "Usage: LD_PRELOAD=" LIBNAME " *\n\n" + LIBNAME " unterstands the following environment variables:\n" + " $RPM_FAKE_RESOLVER ... program which does the NSS resolving (defaults\n" + " to " RESOLVER_PROG ")\n" + " $RPM_FAKE_RESOLVER_UID ... uid of the resolver program\n" + " $RPM_FAKE_RESOLVER_GID ... gid of the resolver program\n" + " $RPM_FAKE_CTX ... vserver context which shall be used for resolver\n" + " and scriptlets\n" + " $RPM_FAKE_CAP ... linux capability remove-mask for the context\n" + " $RPM_FAKE_FLAGS ... vserver flags of the context\n" + " $RPM_FAKE_CHROOT ... directory of the chroot environment\n" + " $RPM_FAKE_NAMESPACE_MOUNTS\n" + " ... colon separated list of directories which will\n" + " umounted before scriptlet execution\n\n" + " $RPM_FAKE_HELP ... shows this message\n" + " $RPM_FAKE_VERSION ... shows the version of this program\n\n" + " $RPM_FAKE_DEBUG ... sets the debuglevel bitmask\n\n" + "Please report bugs to " PACKAGE_BUGREPORT "\n"); + exit(0); +} + +static void +showVersion() +{ + WRITE_MSG(1, + LIBNAME " " VERSION " -- wrapper around rpm\n" + "This program is part of " PACKAGE_STRING "\n\n" + "Copyright (C) 2003 Enrico Scholz\n" + VERSION_COPYRIGHT_DISCLAIMER); + exit(0); +} + +static void +unsetPreloadEnv() +{ + char *env = getenv("LD_PRELOAD"); + char *pos; + + // the const <-> non-const assignment is not an issue since the following + // modifying operations will not be executed in the const-case + env = env ? env : ""; + pos = strstr(env, LIBNAME); + + if (pos!=0) { + char *end_pos = pos + sizeof(LIBNAME); + bool is_end = (end_pos[-1]=='\0'); + char *start_pos; + + end_pos[-1] = '\0'; + start_pos = strrchr(env, ':'); + if (start_pos==0) start_pos = env; + else if (!is_end) ++start_pos; + + if (is_end) *start_pos = '\0'; + else memmove(start_pos, end_pos, strlen(end_pos)+1); + } + +#ifdef DEBUG + if (isDbgLevel(DBG_VERBOSE1|DBG_VARIABLES)) { + WRITE_MSG(2, "env='"); + WRITE_STR(2, env); + WRITE_MSG(2, "'\n"); + } +#endif + + if (*env=='\0') unsetenv("LD_PRELOAD"); +} + +static void +clearEnv() +{ + if (isDbgLevel(DBG_ENV)) WRITE_MSG(2, "clearEnv()\n"); + + unsetenv("RPM_FAKE_S_CONTEXT_REV"); + unsetenv("RPM_FAKE_S_CONTEXT_NR"); + unsetenv("RPM_FAKE_CTX"); + unsetenv("RPM_FAKE_FLAGS"); + unsetenv("RPM_FAKE_CHROOT"); + unsetenv("RPM_FAKE_NAMESPACE_MOUNTS"); + + unsetenv("RPM_FAKE_RESOLVER_GID"); + unsetenv("RPM_FAKE_RESOLVER_UID"); + unsetenv("RPM_FAKE_RESOLVER"); + unsetenv("RPM_FAKE_PWSOCKET"); + + unsetenv("RPM_FAKE_DEBUG"); + + unsetPreloadEnv(); +} + +static int +getDefaultEnv(char const *key, int dflt) +{ + char *env = getenv(key); + int res; + + if (env==0 || env[0]=='\0') res = dflt; + else res = atoi(env); + + return res; +} + + /// \returns true iff we are in ctx after leaving this function +static bool +setupContext(xid_t xid, char const **xid_str) +{ + bool res = false; + + if (vc_isSupported(vcFEATURE_MIGRATE)) { + xid_t rc=VC_NOCTX; + + if ((xid==VC_DYNAMIC_XID || !vc_is_dynamic_xid(xid)) && + (rc=vc_ctx_create(xid))==VC_NOCTX && + errno!=EEXIST) { + perror(ENSC_WRAPPERS_PREFIX "vc_create_context()"); + exit(255); + } + + if (rc!=VC_NOCTX) { + char buf[sizeof(xid_t)*3 + 128]; + size_t l; + struct vc_ctx_caps caps; + + strcpy(buf, "rpm-fake.so #"); + l = utilvserver_fmt_uint(buf+sizeof("rpm-fake.so #")-1, getppid()); + Evc_set_vhi_name(rc, vcVHI_CONTEXT, buf, sizeof("rpm-fake.so #")+l-1); + + caps.ccaps = 0ull; + caps.cmask = ~0ull; + caps.bcaps = ~vc_get_insecurebcaps(); + caps.bmask = ~0ull; + Evc_set_ccaps(rc, &caps); + + // context will be activated later... + + xid = rc; + res = true; + } + } + + if (xid==VC_DYNAMIC_XID) + *xid_str = 0; + else { + char buf[sizeof(xid_t)*3 + 2]; + size_t l; + + l = utilvserver_fmt_uint(buf, xid); buf[l] = '\0'; + *xid_str = strdup(buf); + } + + Ewrite(3, &xid, sizeof xid); + return res; +} + +#if 0 +static void +initPwSocket() +{ + char const * sock_name = getenv("RPM_FAKE_PWSOCKET"); + if (sock_name!=0) { + int flag; + struct sockaddr_un addr = { + .sun_family = AF_UNIX, + }; + + strncpy(addr.sun_path, sock_name, sizeof(addr.sun_path)-1); + addr.sun_path[sizeof(addr.sun_path)-1]='\0'; + + if ((pw_sock=socket(AF_UNIX, SOCK_STREAM, 0))==-1 || + connect(pw_sock, (struct sockaddr *)(&addr), sizeof addr)==-1 || + (flag=fcntl(pw_sock, F_GETFD))==-1 || + fcntl(pw_sock, F_SETFD, flag | FD_CLOEXEC)==-1) { + perror(ENSC_WRAPPERS_PREFIX "error while initializing pw-socket"); + exit(255); + } + } +} +#else +static void +initPwSocket() +{ + char const * resolver = getenv("RPM_FAKE_RESOLVER"); + if (resolver==0) resolver=RESOLVER_PROG; + + if (resolver!=0 && *resolver!='\0') { + int res_sock[2]; + int sync_pipe[2]; + pid_t pid; + char const * uid=0; + char const * gid=0; + + uid=getenv("RPM_FAKE_RESOLVER_UID"); + gid=getenv("RPM_FAKE_RESOLVER_GID"); + + if (socketpair(AF_UNIX, SOCK_STREAM, 0, res_sock)==-1 || + pipe(sync_pipe)==-1 || + fcntl(res_sock[0], F_SETFD, FD_CLOEXEC)==-1 || + fcntl(sync_pipe[0], F_SETFD, FD_CLOEXEC)==-1) { + perror(ENSC_WRAPPERS_PREFIX "failed to create/initialize resolver-socket or pipe"); + exit(255); + } + + pid = fork(); + if (pid==-1) { + perror(ENSC_WRAPPERS_PREFIX "fork()"); + exit(255); + } + + if (pid==0) { + char const *args[20]; + char const **ptr = args; + char const *env[] = { "HOME=/", "PATH=/bin:/usr/bin", 0 }; + char const *xid_str; + char flag_str[ sizeof(flags)*3 + 2]; + char caps_str[ sizeof(caps)*3 + 2]; + + clearEnv(); + + setsid(); + dup2(res_sock[1], 0); + dup2(res_sock[1], 1); + if (sync_pipe[1]!=3) { + close(3); + dup2(sync_pipe[1], 3); + close(sync_pipe[1]); + } + close(res_sock[1]); + /* ... *socket[0] are marked as close-on-exec ...*/ + + flag_str[utilvserver_fmt_uint(flag_str, flags)] = '\0'; + caps_str[utilvserver_fmt_uint(caps_str, caps)] = '\0'; + + *ptr++ = resolver; + *ptr++ = "-F"; *ptr++ = flag_str; + *ptr++ = "-C"; *ptr++ = caps_str; + if (root) { *ptr++ = "-r"; *ptr++ = "."; } + if (uid) { *ptr++ = "-u"; *ptr++ = uid; } + if (gid) { *ptr++ = "-g"; *ptr++ = gid; } + + if (root) Echdir(root); + + if (setupContext(ctx, &xid_str)) { *ptr++ = "-s"; } + else if (xid_str) { *ptr++ = "-c"; *ptr++ = xid_str; } + + *ptr++ = 0; + execve(resolver, (char **)args, (char **)env); + perror(ENSC_WRAPPERS_PREFIX "failed to exec resolver"); + exit(255); + } + else { + uint8_t c; + + close(res_sock[1]); + close(sync_pipe[1]); + pw_sock = res_sock[0]; + sync_sock = sync_pipe[0]; + + if (read(sync_sock, &ctx, sizeof ctx)!=sizeof(ctx) || + read(sync_sock, &c, 1)!=1 || + write(pw_sock, ".", 1)!=1 || + read(pw_sock, &c, 1)!=1 || + c!='.') { + WRITE_MSG(2, ENSC_WRAPPERS_PREFIX "failed to initialize communication with resolver\n"); + exit(255); + } + + if (wait4(pid, 0, WNOHANG,0)==-1) { + WRITE_MSG(2, ENSC_WRAPPERS_PREFIX" unexpected initialization-error of resolver\n"); + exit(255); + } + } + } +} +#endif + +static void +reduceCapabilities() +{ + struct __user_cap_header_struct header; + struct __user_cap_data_struct user; + + header.version = _LINUX_CAPABILITY_VERSION; + header.pid = 0; + + if (capget(&header, &user)==-1) { + perror("capget()"); + exit(wrapper_exit_code); + } + + user.effective &= ~(1<>>>> initRPMFake <<<<<\n"); + + reduceCapabilities(); + initSymbols(); + initEnvironment(); + initPwSocket(); + +#if 0 + if (isDbgLevel(DBG_VARIABLES|DBG_VERBOSE2)) { + + } +#endif +} + +void +exitRPMFake() +{ + if (isDbgLevel(DBG_INIT)) WRITE_MSG(2, ">>>>> exitRPMFake <<<<<\n"); + if (pw_sock!=-1) { + uint8_t c; + if (read(sync_sock, &c, 1)!=1) { /*...*/ } + if (write(pw_sock, "Q", 1)!=1) { /*...*/ } + } +} + + + //============ the worker part =========== + + +static bool +doPwStringRequest(uint32_t *result, char style, char const *name) +{ + uint32_t len = strlen(name); + uint8_t code; + uint8_t c; + + return (TEMP_FAILURE_RETRY(read (sync_sock, &c, 1))==1 && + TEMP_FAILURE_RETRY(write(pw_sock, &style, 1))==1 && + TEMP_FAILURE_RETRY(write(pw_sock, &len, sizeof len))==sizeof(len) && + TEMP_FAILURE_RETRY(write(pw_sock, name, len))==(ssize_t)(len) && + TEMP_FAILURE_RETRY(read (pw_sock, &code, sizeof code))==sizeof(code) && + TEMP_FAILURE_RETRY(read (pw_sock, result, sizeof *result))==sizeof(*result) && + code!=0); +} + +struct passwd * +getpwnam(const char * name) +{ + if (pw_sock==-1) return getpwnam_func(name); + else { + uint32_t id; + static struct passwd res = { + .pw_passwd = "*", + .pw_gid = -1, + .pw_gecos = "", + .pw_dir = "/", + .pw_shell = "/bin/false" + }; + + res.pw_name = (char *)(name); + if (!doPwStringRequest(&id, 'P', name)) return 0; + res.pw_uid = id; + + return &res; + } +} + +struct group * +getgrnam(const char * name) +{ + if (pw_sock==-1) return getgrnam_func(name); + else { + uint32_t id; + static struct group res = { + .gr_passwd = "*", + .gr_mem = 0 + }; + + res.gr_name = (char *)(name); + if (!doPwStringRequest(&id, 'G', name)) return 0; + res.gr_gid = id; + + return &res; + } +} + +void +endgrent() +{ + if (pw_sock==-1) endgrent_func(); + TEMP_FAILURE_RETRY(write(pw_sock, "Cg", 2)); +} + +void +endpwent() +{ + if (pw_sock==-1) endpwent_func(); + TEMP_FAILURE_RETRY(write(pw_sock, "Cp", 2)); +} + + +static int +execvWorker(char const *path, char * const argv[], char * const envp[]) +{ + int res = -1; + + if (vc_isSupported(vcFEATURE_MIGRATE)) + res = vc_ctx_migrate(ctx); + else { +#ifdef VC_ENABLE_API_COMPAT + res = vc_new_s_context(ctx,caps,flags); +#else + WRITE_MSG(2, ENSC_WRAPPERS_PREFIX "can not change context: migrate kernel feature missing and 'compat' API disabled\n"); +#endif + } + + clearEnv(); + + if (res!=-1) + res=execve(path, argv, envp); + + return res; +} + +struct ExecvParams +{ + char const * path; + char * const * argv; + char * const * envp; + char const * mnts; +}; + +static int +removeNamespaceMountsChild(struct ExecvParams const *params) +{ + char buf[strlen(params->mnts)+1], *ptr; + + strcpy(buf, params->mnts); + ptr = strtok(buf, ":"); + while (ptr) { + if (umount2(ptr, 0)==-1) { + // FIXME: What is the semantic for CLONE_NEWNS? Is it ok that mounts in + // chroots are visible only, when chroot is on /dev/root? + // + // For now, ignore any errors, but future versions should handle them. + + //return -1; + } + ptr = strtok(0, ":"); + } + + return execvWorker(params->path, params->argv, params->envp); +} + +static int +removeNamespaceMounts(char const *path, + char * const argv[], char * const envp[]) +{ + if (mnts==0) return execvWorker(path, argv, envp); + + { + int status; + pid_t p, pid; + struct ExecvParams params; + + params.path = path; + params.argv = argv; + params.envp = envp; + params.mnts = mnts; + + // the rpmlib signal-handler is still active; use the default one to + // make wait4() working... + signal(SIGCHLD, SIG_DFL); + +#ifdef NDEBUG + pid = sys_clone(CLONE_NEWNS|SIGCHLD|CLONE_VFORK, 0); +#else + pid = sys_clone(CLONE_NEWNS|SIGCHLD, 0); +#endif + + switch (pid) { + case -1 : return -1; + case 0 : _exit(removeNamespaceMountsChild(¶ms)); + default : break; + } + + while ((p=wait4(pid, &status, 0,0))==-1 && + (errno==EINTR || errno==EAGAIN)) ; + + if (p==-1) return -1; + + if (WIFEXITED(status)) _exit(WEXITSTATUS(status)); + if (WIFSIGNALED(status)) kill(getpid(), WTERMSIG(status)); + + return -1; + } +} + + +int +execv(char const *path, char * const argv[]) +{ + extern char **environ; + + if (isDbgLevel(DBG_EXECV)) { + WRITE_MSG(2, "execv('"); + WRITE_STR(2, path); + WRITE_MSG(2, "', ...)\n"); + } + + return removeNamespaceMounts(path, argv, environ); +} + +int +rpm_execcon(unsigned int UNUSED verified, + const char *filename, + char *const argv[], char *const envp[]) +{ + if (isDbgLevel(DBG_EXECV)) { + WRITE_MSG(2, "rpm_execcon(..., '"); + WRITE_STR(2, filename); + WRITE_MSG(2, "', ...)\n"); + } + + return removeNamespaceMounts(filename, argv, envp); +} + +int +is_selinux_enabled() +{ + return 0; +}