diff --git a/MANIFEST b/MANIFEST index be7dad1bf..f1c1ee3e4 100644 --- a/MANIFEST +++ b/MANIFEST @@ -661,6 +661,7 @@ plugins/sudoers/mkdefaults plugins/sudoers/parse.c plugins/sudoers/parse.h plugins/sudoers/parse_ldif.c +plugins/sudoers/pivot.c plugins/sudoers/po/README plugins/sudoers/po/ast.mo plugins/sudoers/po/ast.po diff --git a/plugins/sudoers/Makefile.in b/plugins/sudoers/Makefile.in index 3dcc746f2..b2174332c 100644 --- a/plugins/sudoers/Makefile.in +++ b/plugins/sudoers/Makefile.in @@ -176,7 +176,7 @@ AUTH_OBJS = sudo_auth.lo @AUTH_OBJS@ LIBPARSESUDOERS_OBJS = alias.lo b64_decode.lo defaults.lo digestname.lo \ exptilde.lo filedigest.lo gentime.lo gram.lo \ match.lo match_addr.lo match_command.lo \ - match_digest.lo pwutil.lo pwutil_impl.lo \ + match_digest.lo pivot.lo pwutil.lo pwutil_impl.lo \ redblack.lo strlist.lo sudoers_debug.lo timeout.lo \ timestr.lo toke.lo toke_util.lo @@ -2378,6 +2378,26 @@ passwd.i: $(authdir)/passwd.c $(authdir)/sudo_auth.h $(devdir)/def_data.h \ $(CC) -E -o $@ $(CPPFLAGS) $< passwd.plog: passwd.i rm -f $@; pvs-studio --cfg $(PVS_CFG) --sourcetree-root $(top_srcdir) --skip-cl-exe yes --source-file $(authdir)/passwd.c --i-file $< --output-file $@ +pivot.lo: $(srcdir)/pivot.c $(devdir)/def_data.h $(incdir)/compat/stdbool.h \ + $(incdir)/sudo_compat.h $(incdir)/sudo_conf.h $(incdir)/sudo_debug.h \ + $(incdir)/sudo_eventlog.h $(incdir)/sudo_fatal.h \ + $(incdir)/sudo_gettext.h $(incdir)/sudo_plugin.h \ + $(incdir)/sudo_queue.h $(incdir)/sudo_util.h $(srcdir)/defaults.h \ + $(srcdir)/logging.h $(srcdir)/parse.h $(srcdir)/sudo_nss.h \ + $(srcdir)/sudoers.h $(srcdir)/sudoers_debug.h \ + $(top_builddir)/config.h $(top_builddir)/pathnames.h + $(LIBTOOL) $(LTFLAGS) --mode=compile $(CC) -c $(CPPFLAGS) $(CFLAGS) $(ASAN_CFLAGS) $(PIE_CFLAGS) $(HARDENING_CFLAGS) $(srcdir)/pivot.c +pivot.i: $(srcdir)/pivot.c $(devdir)/def_data.h $(incdir)/compat/stdbool.h \ + $(incdir)/sudo_compat.h $(incdir)/sudo_conf.h $(incdir)/sudo_debug.h \ + $(incdir)/sudo_eventlog.h $(incdir)/sudo_fatal.h \ + $(incdir)/sudo_gettext.h $(incdir)/sudo_plugin.h \ + $(incdir)/sudo_queue.h $(incdir)/sudo_util.h $(srcdir)/defaults.h \ + $(srcdir)/logging.h $(srcdir)/parse.h $(srcdir)/sudo_nss.h \ + $(srcdir)/sudoers.h $(srcdir)/sudoers_debug.h \ + $(top_builddir)/config.h $(top_builddir)/pathnames.h + $(CC) -E -o $@ $(CPPFLAGS) $< +pivot.plog: pivot.i + rm -f $@; pvs-studio --cfg $(PVS_CFG) --sourcetree-root $(top_srcdir) --skip-cl-exe yes --source-file $(srcdir)/pivot.c --i-file $< --output-file $@ policy.lo: $(srcdir)/policy.c $(devdir)/def_data.h $(incdir)/compat/stdbool.h \ $(incdir)/sudo_compat.h $(incdir)/sudo_conf.h \ $(incdir)/sudo_debug.h $(incdir)/sudo_eventlog.h \ @@ -2925,8 +2945,9 @@ sudoreplay.o: $(srcdir)/sudoreplay.c $(incdir)/compat/getopt.h \ $(incdir)/sudo_conf.h $(incdir)/sudo_debug.h \ $(incdir)/sudo_event.h $(incdir)/sudo_eventlog.h \ $(incdir)/sudo_fatal.h $(incdir)/sudo_gettext.h \ - $(incdir)/sudo_iolog.h $(incdir)/sudo_plugin.h \ - $(incdir)/sudo_queue.h $(incdir)/sudo_util.h $(srcdir)/logging.h \ + $(incdir)/sudo_iolog.h $(incdir)/sudo_lbuf.h \ + $(incdir)/sudo_plugin.h $(incdir)/sudo_queue.h \ + $(incdir)/sudo_util.h $(srcdir)/logging.h \ $(top_builddir)/config.h $(top_builddir)/pathnames.h $(CC) -c $(CPPFLAGS) $(CFLAGS) $(ASAN_CFLAGS) $(PIE_CFLAGS) $(HARDENING_CFLAGS) $(srcdir)/sudoreplay.c sudoreplay.i: $(srcdir)/sudoreplay.c $(incdir)/compat/getopt.h \ @@ -2934,8 +2955,9 @@ sudoreplay.i: $(srcdir)/sudoreplay.c $(incdir)/compat/getopt.h \ $(incdir)/sudo_conf.h $(incdir)/sudo_debug.h \ $(incdir)/sudo_event.h $(incdir)/sudo_eventlog.h \ $(incdir)/sudo_fatal.h $(incdir)/sudo_gettext.h \ - $(incdir)/sudo_iolog.h $(incdir)/sudo_plugin.h \ - $(incdir)/sudo_queue.h $(incdir)/sudo_util.h $(srcdir)/logging.h \ + $(incdir)/sudo_iolog.h $(incdir)/sudo_lbuf.h \ + $(incdir)/sudo_plugin.h $(incdir)/sudo_queue.h \ + $(incdir)/sudo_util.h $(srcdir)/logging.h \ $(top_builddir)/config.h $(top_builddir)/pathnames.h $(CC) -E -o $@ $(CPPFLAGS) $< sudoreplay.plog: sudoreplay.i diff --git a/plugins/sudoers/pivot.c b/plugins/sudoers/pivot.c new file mode 100644 index 000000000..b7a01356e --- /dev/null +++ b/plugins/sudoers/pivot.c @@ -0,0 +1,90 @@ +/* + * SPDX-License-Identifier: ISC + * + * Copyright (c) 2023 Todd C. Miller + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +/* + * This is an open source non-commercial project. Dear PVS-Studio, please check it. + * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com + */ + +#include + +#include +#include +#include + +#include "sudoers.h" + +#define OLD_ROOT 0 +#define OLD_CWD 1 + +/* + * Pivot to a new root directory, storing the old root and old cwd + * in fds[2]. Changes current working directory to the new root. + * Returns true on success, else false. + */ +bool +pivot_root(const char *new_root, int fds[2]) +{ + debug_decl(pivot_root, SUDOERS_DEBUG_UTIL); + + fds[OLD_ROOT] = open("/", O_RDONLY); + fds[OLD_CWD] = open(".", O_RDONLY); + if (fds[OLD_ROOT] == -1 || fds[OLD_CWD] == -1 || chroot(new_root) == -1) { + if (fds[OLD_ROOT] != -1) { + close(fds[OLD_ROOT]); + fds[OLD_ROOT] = -1; + } + if (fds[OLD_CWD] != -1) { + close(fds[OLD_CWD]); + fds[OLD_CWD] = -1; + } + debug_return_bool(false); + } + debug_return_bool(chdir("/") == 0); +} + +/* + * Pivot back to the stored root directory and restore the old cwd. + * Returns true on success, else false. + */ +bool +unpivot_root(int fds[2]) +{ + bool ret = true; + debug_decl(unpivot_root, SUDOERS_DEBUG_UTIL); + + /* Order is imporant: restore old root, *then* change cwd. */ + if (fds[OLD_ROOT] != -1) { + if (fchdir(fds[OLD_ROOT]) == -1 || chroot(".") == -1) { + sudo_warn("%s", U_("unable to restore root directory")); + ret = false; + } + close(fds[OLD_ROOT]); + fds[OLD_ROOT] = -1; + } + if (fds[OLD_CWD] != -1) { + if (fchdir(fds[OLD_CWD]) == -1) { + sudo_warn("%s", U_("unable to restore current working directory")); + ret = false; + } + close(fds[OLD_CWD]); + fds[OLD_CWD] = -1; + } + + debug_return_bool(ret); +} diff --git a/plugins/sudoers/sudoers.h b/plugins/sudoers/sudoers.h index df60627c1..5f9e545fd 100644 --- a/plugins/sudoers/sudoers.h +++ b/plugins/sudoers/sudoers.h @@ -489,4 +489,8 @@ void unescape_string(char *str); /* serialize_list.c */ char *serialize_list(const char *varname, struct list_members *members); +/* pivot_root.c */ +bool pivot_root(const char *new_root, int fds[2]); +bool unpivot_root(int fds[2]); + #endif /* SUDOERS_SUDOERS_H */