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/*
* Phusion Passenger - https://www.phusionpassenger.com/
* Copyright (c) 2011-2018 Phusion Holding B.V.
*
* "Passenger", "Phusion Passenger" and "Union Station" are registered
* trademarks of Phusion Holding B.V.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef _PASSENGER_SPAWNING_KIT_USER_SWITCHING_RULES_H_
#define _PASSENGER_SPAWNING_KIT_USER_SWITCHING_RULES_H_
#include <sys/types.h>
#include <pwd.h>
#include <grp.h>
#include <unistd.h>
#include <string>
#include <algorithm>
#include <boost/shared_array.hpp>
#include <oxt/backtrace.hpp>
#include <oxt/system_calls.hpp>
#include <WrapperRegistry/Registry.h>
#include <Exceptions.h>
#include <Utils.h>
#include <Core/SpawningKit/Context.h>
#include <FileTools/PathManip.h>
#include <SystemTools/UserDatabase.h>
namespace Passenger {
namespace SpawningKit {
using namespace std;
using namespace boost;
using namespace oxt;
struct UserSwitchingInfo {
bool enabled;
string username;
string groupname;
uid_t uid;
gid_t gid;
struct passwd lveUserPwd, *lveUserPwdComplete;
boost::shared_array<char> lveUserPwdStrBuf;
};
inline UserSwitchingInfo
prepareUserSwitching(const AppPoolOptions &options,
const WrapperRegistry::Registry &wrapperRegistry)
{
TRACE_POINT();
UserSwitchingInfo info;
if (geteuid() != 0) {
struct passwd &pwd = info.lveUserPwd;
boost::shared_array<char> &strings = info.lveUserPwdStrBuf;
struct passwd *userInfo;
long bufSize;
// _SC_GETPW_R_SIZE_MAX is not a maximum:
// http://tomlee.co/2012/10/problems-with-large-linux-unix-groups-and-getgrgid_r-getgrnam_r/
bufSize = std::max<long>(1024 * 128, sysconf(_SC_GETPW_R_SIZE_MAX));
strings.reset(new char[bufSize]);
userInfo = (struct passwd *) NULL;
if (getpwuid_r(geteuid(), &pwd, strings.get(), bufSize, &userInfo) != 0
|| userInfo == (struct passwd *) NULL)
{
throw RuntimeException("Cannot get user database entry for user " +
lookupSystemUsernameByUid(geteuid()) + "; it looks like your system's " +
"user database is broken, please fix it.");
}
info.enabled = false;
info.username = userInfo->pw_name;
info.groupname = lookupSystemGroupnameByGid(userInfo->pw_gid, true);
info.uid = geteuid();
info.gid = getegid();
return info;
}
UPDATE_TRACE_POINT();
string defaultGroup;
// This is the file that determines what user we lower privilege to.
string referenceFile;
struct passwd &pwd = info.lveUserPwd;
boost::shared_array<char> &pwdBuf = info.lveUserPwdStrBuf;
struct passwd *userInfo;
struct group grp;
gid_t groupId = (gid_t) -1;
long pwdBufSize, grpBufSize;
boost::shared_array<char> grpBuf;
int ret;
if (options.appType.empty()) {
referenceFile = absolutizePath(options.appRoot);
} else {
referenceFile = absolutizePath(options.getStartupFile(wrapperRegistry),
absolutizePath(options.appRoot));
}
// _SC_GETPW_R_SIZE_MAX/_SC_GETGR_R_SIZE_MAX are not maximums:
// http://tomlee.co/2012/10/problems-with-large-linux-unix-groups-and-getgrgid_r-getgrnam_r/
pwdBufSize = std::max<long>(1024 * 128, sysconf(_SC_GETPW_R_SIZE_MAX));
pwdBuf.reset(new char[pwdBufSize]);
grpBufSize = std::max<long>(1024 * 128, sysconf(_SC_GETGR_R_SIZE_MAX));
grpBuf.reset(new char[grpBufSize]);
if (options.defaultGroup.empty()) {
struct passwd *info;
struct group *group;
info = (struct passwd *) NULL;
ret = getpwnam_r(options.defaultUser.c_str(), &pwd, pwdBuf.get(),
pwdBufSize, &info);
if (ret != 0) {
info = (struct passwd *) NULL;
}
if (info == (struct passwd *) NULL) {
throw RuntimeException("Cannot get user database entry for username '" +
options.defaultUser + "'");
}
group = (struct group *) NULL;
ret = getgrgid_r(info->pw_gid, &grp, grpBuf.get(), grpBufSize, &group);
if (ret != 0) {
group = (struct group *) NULL;
}
if (group == (struct group *) NULL) {
throw RuntimeException(string("Cannot get group database entry for ") +
"the default group belonging to username '" +
options.defaultUser + "'");
}
defaultGroup = group->gr_name;
} else {
defaultGroup = options.defaultGroup;
}
UPDATE_TRACE_POINT();
userInfo = (struct passwd *) NULL;
if (!options.userSwitching) {
// Keep userInfo at NULL so that it's set to defaultUser's UID.
} else if (!options.user.empty()) {
ret = getpwnam_r(options.user.c_str(), &pwd, pwdBuf.get(),
pwdBufSize, &userInfo);
if (ret != 0) {
userInfo = (struct passwd *) NULL;
}
} else {
struct stat buf;
if (syscalls::lstat(referenceFile.c_str(), &buf) == -1) {
int e = errno;
throw SystemException("Cannot lstat(\"" + referenceFile +
"\")", e);
}
ret = getpwuid_r(buf.st_uid, &pwd, pwdBuf.get(),
pwdBufSize, &userInfo);
if (ret != 0) {
userInfo = (struct passwd *) NULL;
}
}
if (userInfo == (struct passwd *) NULL || userInfo->pw_uid == 0) {
userInfo = (struct passwd *) NULL;
ret = getpwnam_r(options.defaultUser.c_str(), &pwd,
pwdBuf.get(), pwdBufSize, &userInfo);
if (ret != 0) {
userInfo = (struct passwd *) NULL;
}
}
UPDATE_TRACE_POINT();
if (!options.userSwitching) {
// Keep groupId at -1 so that it's set to defaultGroup's GID.
} else if (!options.group.empty()) {
struct group *groupInfo = (struct group *) NULL;
if (options.group == "!STARTUP_FILE!") {
struct stat buf;
if (syscalls::lstat(referenceFile.c_str(), &buf) == -1) {
int e = errno;
throw SystemException("Cannot lstat(\"" +
referenceFile + "\")", e);
}
ret = getgrgid_r(buf.st_gid, &grp, grpBuf.get(), grpBufSize,
&groupInfo);
if (ret != 0) {
groupInfo = (struct group *) NULL;
}
if (groupInfo != NULL) {
groupId = buf.st_gid;
} else {
groupId = (gid_t) -1;
}
} else {
ret = getgrnam_r(options.group.c_str(), &grp, grpBuf.get(),
grpBufSize, &groupInfo);
if (ret != 0) {
groupInfo = (struct group *) NULL;
}
if (groupInfo != NULL) {
groupId = groupInfo->gr_gid;
} else {
groupId = (gid_t) -1;
}
}
} else if (userInfo != (struct passwd *) NULL) {
groupId = userInfo->pw_gid;
}
if (groupId == 0 || groupId == (gid_t) -1) {
OsGroup osGroup;
if (lookupSystemGroupByName(defaultGroup, osGroup)) {
groupId = osGroup.grp.gr_gid;
} else if (looksLikePositiveNumber(defaultGroup)) {
groupId = atoi(defaultGroup);
} else {
groupId = -1;
}
}
UPDATE_TRACE_POINT();
if (userInfo == (struct passwd *) NULL) {
throw RuntimeException("Cannot determine a user to lower privilege to");
}
if (groupId == (gid_t) -1) {
throw RuntimeException("Cannot determine a group to lower privilege to");
}
UPDATE_TRACE_POINT();
info.enabled = true;
info.username = userInfo->pw_name;
info.groupname = lookupSystemGroupnameByGid(groupId, true);
info.uid = userInfo->pw_uid;
info.gid = groupId;
return info;
}
} // namespace SpawningKit
} // namespace Passenger
#endif /* _PASSENGER_SPAWNING_KIT_USER_SWITCHING_RULES_H_ */
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