* Move setuid stuff to libutil.
* Install libexpr header files.
This commit is contained in:
Eelco Dolstra
parent
e5a6c09b12
commit
bafc1690fc
4 changed files with 146 additions and 142 deletions
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@ -1,11 +1,12 @@
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pkglib_LTLIBRARIES = libexpr.la
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libexpr_la_SOURCES = nixexpr.cc nixexpr.hh \
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eval.cc eval.hh primops.cc \
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lexer-tab.cc lexer-tab.hh parser-tab.cc parser-tab.hh \
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get-drvs.cc get-drvs.hh \
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attr-path.cc attr-path.hh \
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expr-to-xml.cc expr-to-xml.hh
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libexpr_la_SOURCES = \
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nixexpr.cc eval.cc primops.cc lexer-tab.cc parser-tab.cc \
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get-drvs.cc attr-path.cc expr-to-xml.cc
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pkginclude_HEADERS = \
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nixexpr.hh eval.hh parser.hh lexer-tab.hh parser-tab.hh \
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get-drvs.hh attr-path.hh expr-to-xml.hh
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libexpr_la_LIBADD = ../libutil/libutil.la ../libstore/libstore.la \
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../boost/format/libformat.la
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@ -207,139 +207,6 @@ static void initAndRun(int argc, char * * argv)
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}
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static bool haveSwitched;
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static uid_t savedUid, nixUid;
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static gid_t savedGid, nixGid;
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#if HAVE_SETRESUID
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#define _setuid(uid) setresuid(uid, uid, savedUid)
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#define _setgid(gid) setresgid(gid, gid, savedGid)
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#else
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/* Only works properly when run by root. */
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#define _setuid(uid) setuid(uid)
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#define _setgid(gid) setgid(gid)
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#endif
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SwitchToOriginalUser::SwitchToOriginalUser()
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{
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#if SETUID_HACK && HAVE_SETRESUID
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/* Temporarily switch the effective uid/gid back to the saved
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uid/gid (which is the uid/gid of the user that executed the Nix
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program; it's *not* the real uid/gid, since we changed that to
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the Nix user in switchToNixUser()). */
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if (haveSwitched) {
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if (setuid(savedUid) == -1)
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throw SysError(format("temporarily restoring uid to `%1%'") % savedUid);
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if (setgid(savedGid) == -1)
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throw SysError(format("temporarily restoring gid to `%1%'") % savedGid);
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}
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#endif
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}
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SwitchToOriginalUser::~SwitchToOriginalUser()
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{
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#if SETUID_HACK && HAVE_SETRESUID
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/* Switch the effective uid/gid back to the Nix user. */
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if (haveSwitched) {
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if (setuid(nixUid) == -1)
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throw SysError(format("restoring uid to `%1%'") % nixUid);
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if (setgid(nixGid) == -1)
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throw SysError(format("restoring gid to `%1%'") % nixGid);
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}
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#endif
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}
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void switchToNixUser()
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{
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#if SETUID_HACK
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/* Don't do anything if this is not a setuid binary. */
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if (getuid() == geteuid() && getgid() == getegid()) return;
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/* Here we set the uid and gid to the Nix user and group,
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respectively, IF the current (real) user is a member of the Nix
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group. Otherwise we just drop all privileges. */
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/* Lookup the Nix gid. */
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struct group * gr = getgrnam(NIX_GROUP);
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if (!gr) {
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cerr << format("missing group `%1%'\n") % NIX_GROUP;
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exit(1);
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}
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/* Get the supplementary group IDs for the current user. */
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int maxGids = 512, nrGids;
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gid_t gids[maxGids];
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if ((nrGids = getgroups(maxGids, gids)) == -1) {
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cerr << format("unable to query gids\n");
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exit(1);
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}
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/* !!! Apparently it is unspecified whether getgroups() includes
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the effective gid. In that case the following test is always
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true *if* the program is installed setgid (which we do when we
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have setresuid()). On Linux this doesn't appear to be the
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case, but we should switch to the real gid before doing this
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test, and then switch back to the saved gid. */
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/* Check that the current user is a member of the Nix group. */
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bool found = false;
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for (int i = 0; i < nrGids; ++i)
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if (gids[i] == gr->gr_gid) {
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found = true;
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break;
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}
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if (!found) {
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/* Not in the Nix group - drop all root/Nix privileges. */
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_setgid(getgid());
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_setuid(getuid());
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return;
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}
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savedUid = getuid();
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savedGid = getgid();
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/* Set the real, effective and saved gids to gr->gr_gid. Also
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make very sure that this succeeded. We switch the gid first
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because we cannot do it after we have dropped root uid. */
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nixGid = gr->gr_gid;
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if (_setgid(nixGid) != 0 || getgid() != nixGid || getegid() != nixGid) {
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cerr << format("unable to set gid to `%1%'\n") % NIX_GROUP;
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exit(1);
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}
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/* Lookup the Nix uid. */
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struct passwd * pw = getpwnam(NIX_USER);
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if (!pw) {
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cerr << format("missing user `%1%'\n") % NIX_USER;
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exit(1);
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}
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/* This will drop all root privileges, setting the real, effective
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and saved uids to pw->pw_uid. Also make very sure that this
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succeeded.*/
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nixUid = pw->pw_uid;
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if (_setuid(nixUid) != 0 || getuid() != nixUid || geteuid() != nixUid) {
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cerr << format("unable to set uid to `%1%'\n") % NIX_USER;
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exit(1);
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}
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/* !!! for setuid operation, we should: 1) wipe the environment;
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2) verify file descriptors 0, 1, 2; 3) etc.
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See: http://www.daemon-systems.org/man/setuid.7.html
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*/
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haveSwitched = true;
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#endif
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}
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}
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@ -850,4 +850,140 @@ bool string2Int(const string & s, int & n)
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}
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//////////////////////////////////////////////////////////////////////
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static bool haveSwitched;
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static uid_t savedUid, nixUid;
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static gid_t savedGid, nixGid;
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#if HAVE_SETRESUID
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#define _setuid(uid) setresuid(uid, uid, savedUid)
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#define _setgid(gid) setresgid(gid, gid, savedGid)
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#else
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/* Only works properly when run by root. */
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#define _setuid(uid) setuid(uid)
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#define _setgid(gid) setgid(gid)
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#endif
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SwitchToOriginalUser::SwitchToOriginalUser()
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{
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#if SETUID_HACK && HAVE_SETRESUID
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/* Temporarily switch the effective uid/gid back to the saved
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uid/gid (which is the uid/gid of the user that executed the Nix
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program; it's *not* the real uid/gid, since we changed that to
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the Nix user in switchToNixUser()). */
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if (haveSwitched) {
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if (setuid(savedUid) == -1)
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throw SysError(format("temporarily restoring uid to `%1%'") % savedUid);
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if (setgid(savedGid) == -1)
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throw SysError(format("temporarily restoring gid to `%1%'") % savedGid);
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}
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#endif
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}
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SwitchToOriginalUser::~SwitchToOriginalUser()
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{
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#if SETUID_HACK && HAVE_SETRESUID
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/* Switch the effective uid/gid back to the Nix user. */
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if (haveSwitched) {
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if (setuid(nixUid) == -1)
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throw SysError(format("restoring uid to `%1%'") % nixUid);
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if (setgid(nixGid) == -1)
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throw SysError(format("restoring gid to `%1%'") % nixGid);
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}
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#endif
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}
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void switchToNixUser()
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{
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#if SETUID_HACK
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/* Don't do anything if this is not a setuid binary. */
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if (getuid() == geteuid() && getgid() == getegid()) return;
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/* Here we set the uid and gid to the Nix user and group,
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respectively, IF the current (real) user is a member of the Nix
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group. Otherwise we just drop all privileges. */
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/* Lookup the Nix gid. */
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struct group * gr = getgrnam(NIX_GROUP);
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if (!gr) {
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cerr << format("missing group `%1%'\n") % NIX_GROUP;
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exit(1);
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}
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/* Get the supplementary group IDs for the current user. */
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int maxGids = 512, nrGids;
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gid_t gids[maxGids];
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if ((nrGids = getgroups(maxGids, gids)) == -1) {
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cerr << format("unable to query gids\n");
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exit(1);
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}
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/* !!! Apparently it is unspecified whether getgroups() includes
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the effective gid. In that case the following test is always
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true *if* the program is installed setgid (which we do when we
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have setresuid()). On Linux this doesn't appear to be the
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case, but we should switch to the real gid before doing this
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test, and then switch back to the saved gid. */
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/* Check that the current user is a member of the Nix group. */
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bool found = false;
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for (int i = 0; i < nrGids; ++i)
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if (gids[i] == gr->gr_gid) {
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found = true;
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break;
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}
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if (!found) {
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/* Not in the Nix group - drop all root/Nix privileges. */
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_setgid(getgid());
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_setuid(getuid());
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return;
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}
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savedUid = getuid();
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savedGid = getgid();
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/* Set the real, effective and saved gids to gr->gr_gid. Also
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make very sure that this succeeded. We switch the gid first
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because we cannot do it after we have dropped root uid. */
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nixGid = gr->gr_gid;
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if (_setgid(nixGid) != 0 || getgid() != nixGid || getegid() != nixGid) {
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cerr << format("unable to set gid to `%1%'\n") % NIX_GROUP;
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exit(1);
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}
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/* Lookup the Nix uid. */
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struct passwd * pw = getpwnam(NIX_USER);
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if (!pw) {
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cerr << format("missing user `%1%'\n") % NIX_USER;
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exit(1);
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}
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/* This will drop all root privileges, setting the real, effective
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and saved uids to pw->pw_uid. Also make very sure that this
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succeeded.*/
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nixUid = pw->pw_uid;
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if (_setuid(nixUid) != 0 || getuid() != nixUid || geteuid() != nixUid) {
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cerr << format("unable to set uid to `%1%'\n") % NIX_USER;
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exit(1);
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}
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/* !!! for setuid operation, we should: 1) wipe the environment;
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2) verify file descriptors 0, 1, 2; 3) etc.
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See: http://www.daemon-systems.org/man/setuid.7.html
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*/
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haveSwitched = true;
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#endif
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}
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}
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@ -246,15 +246,15 @@ string int2String(int n);
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bool string2Int(const string & s, int & n);
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/* !!! HACK HACK HACK - this should be in shared.hh, but it's to
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facilitate a quick hack - will remove this eventually (famous last
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words). */
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/* Setuid support. */
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struct SwitchToOriginalUser
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{
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SwitchToOriginalUser();
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~SwitchToOriginalUser();
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};
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void switchToNixUser();
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}
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