346 lines
12 KiB
Diff
346 lines
12 KiB
Diff
diff -up ./src/exec_monitor.c.symbolic-link-attack-3 ./src/exec_monitor.c
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--- ./src/exec_monitor.c.symbolic-link-attack-3 2019-10-28 13:27:39.000000000 +0100
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+++ ./src/exec_monitor.c 2021-02-02 17:11:32.382020407 +0100
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@@ -613,7 +613,7 @@ exec_monitor(struct command_details *det
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#ifdef HAVE_SELINUX
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if (ISSET(details->flags, CD_RBAC_ENABLED)) {
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if (selinux_setup(details->selinux_role, details->selinux_type,
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- details->tty, io_fds[SFD_SLAVE]) == -1)
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+ details->tty, io_fds[SFD_SLAVE], true) == -1)
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goto bad;
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}
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#endif
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diff -up ./src/exec_nopty.c.symbolic-link-attack-3 ./src/exec_nopty.c
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--- ./src/exec_nopty.c.symbolic-link-attack-3 2019-10-28 13:27:39.000000000 +0100
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+++ ./src/exec_nopty.c 2021-02-02 17:11:32.382020407 +0100
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@@ -381,7 +381,7 @@ exec_nopty(struct command_details *detai
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#ifdef HAVE_SELINUX
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if (ISSET(details->flags, CD_RBAC_ENABLED)) {
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if (selinux_setup(details->selinux_role, details->selinux_type,
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- details->tty, -1) == -1) {
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+ details->tty, -1, true) == -1) {
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cstat->type = CMD_ERRNO;
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cstat->val = errno;
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debug_return;
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diff -up ./src/selinux.c.symbolic-link-attack-3 ./src/selinux.c
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--- ./src/selinux.c.symbolic-link-attack-3 2019-10-28 13:27:39.000000000 +0100
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+++ ./src/selinux.c 2021-02-02 17:11:32.382020407 +0100
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@@ -363,7 +363,7 @@ bad:
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*/
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int
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selinux_setup(const char *role, const char *type, const char *ttyn,
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- int ptyfd)
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+ int ptyfd, bool label_tty)
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{
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int ret = -1;
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debug_decl(selinux_setup, SUDO_DEBUG_SELINUX)
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@@ -392,7 +392,7 @@ selinux_setup(const char *role, const ch
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sudo_debug_printf(SUDO_DEBUG_INFO, "%s: new context %s", __func__,
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se_state.new_context);
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- if (relabel_tty(ttyn, ptyfd) == -1) {
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+ if (label_tty && relabel_tty(ttyn, ptyfd) == -1) {
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sudo_warn(U_("unable to set tty context to %s"), se_state.new_context);
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goto done;
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}
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@@ -408,6 +408,28 @@ done:
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debug_return_int(ret);
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}
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+int
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+selinux_setcon(void)
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+{
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+ debug_decl(selinux_setcon, SUDO_DEBUG_SELINUX);
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+
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+ if (setexeccon(se_state.new_context)) {
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+ sudo_warn(U_("unable to set exec context to %s"), se_state.new_context);
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+ if (se_state.enforcing)
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+ debug_return_int(-1);
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+ }
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+
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+#ifdef HAVE_SETKEYCREATECON
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+ if (setkeycreatecon(se_state.new_context)) {
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+ sudo_warn(U_("unable to set key creation context to %s"), se_state.new_context);
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+ if (se_state.enforcing)
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+ debug_return_int(-1);
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+ }
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+#endif /* HAVE_SETKEYCREATECON */
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+
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+ debug_return_int(0);
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+}
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+
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void
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selinux_execve(int fd, const char *path, char *const argv[], char *envp[],
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bool noexec)
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@@ -424,19 +446,9 @@ selinux_execve(int fd, const char *path,
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debug_return;
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}
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- if (setexeccon(se_state.new_context)) {
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- sudo_warn(U_("unable to set exec context to %s"), se_state.new_context);
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- if (se_state.enforcing)
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- debug_return;
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- }
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-
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-#ifdef HAVE_SETKEYCREATECON
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- if (setkeycreatecon(se_state.new_context)) {
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- sudo_warn(U_("unable to set key creation context to %s"), se_state.new_context);
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- if (se_state.enforcing)
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- debug_return;
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- }
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-#endif /* HAVE_SETKEYCREATECON */
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+ /* Set SELinux exec and keycreate contexts. */
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+ if (selinux_setcon() == -1)
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+ debug_return;
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/*
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* Build new argv with sesh as argv[0].
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diff -up ./src/sudo.c.symbolic-link-attack-3 ./src/sudo.c
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--- ./src/sudo.c.symbolic-link-attack-3 2021-02-02 17:12:32.773182386 +0100
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+++ ./src/sudo.c 2021-02-02 17:12:48.510964009 +0100
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@@ -971,10 +971,6 @@ run_command(struct command_details *deta
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case CMD_WSTATUS:
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/* Command ran, exited or was killed. */
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status = cstat.val;
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-#ifdef HAVE_SELINUX
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- if (ISSET(details->flags, CD_SUDOEDIT_COPY))
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- break;
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-#endif
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sudo_debug_printf(SUDO_DEBUG_DEBUG,
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"calling policy close with wait status %d", status);
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policy_close(&policy_plugin, status, 0);
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diff -up ./src/sudo_edit.c.symbolic-link-attack-3 ./src/sudo_edit.c
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--- ./src/sudo_edit.c.symbolic-link-attack-3 2021-02-02 17:11:32.380020435 +0100
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+++ ./src/sudo_edit.c 2021-02-02 17:11:32.382020407 +0100
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@@ -757,28 +757,54 @@ bad:
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#ifdef HAVE_SELINUX
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static int
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+selinux_run_helper(char *argv[], char *envp[])
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+{
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+ int status, ret = SESH_ERR_FAILURE;
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+ const char *sesh;
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+ pid_t child, pid;
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+ debug_decl(selinux_run_helper, SUDO_DEBUG_EDIT);
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+
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+ sesh = sudo_conf_sesh_path();
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+ if (sesh == NULL) {
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+ sudo_warnx("internal error: sesh path not set");
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+ debug_return_int(-1);
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+ }
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+
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+ child = sudo_debug_fork();
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+ switch (child) {
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+ case -1:
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+ sudo_warn(U_("unable to fork"));
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+ break;
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+ case 0:
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+ /* child runs sesh in new context */
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+ if (selinux_setcon() == 0)
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+ execve(sesh, argv, envp);
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+ _exit(SESH_ERR_FAILURE);
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+ default:
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+ /* parent waits */
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+ do {
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+ pid = waitpid(child, &status, 0);
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+ } while (pid == -1 && errno == EINTR);
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+
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+ ret = WIFSIGNALED(status) ? SESH_ERR_KILLED : WEXITSTATUS(status);
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+ }
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+
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+ debug_return_int(ret);
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+}
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+
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+static int
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selinux_edit_create_tfiles(struct command_details *command_details,
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struct tempfile *tf, char *files[], int nfiles)
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{
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char **sesh_args, **sesh_ap;
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int i, rc, sesh_nargs;
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struct stat sb;
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- struct command_details saved_command_details;
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debug_decl(selinux_edit_create_tfiles, SUDO_DEBUG_EDIT)
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-
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- /* Prepare selinux stuff (setexeccon) */
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- if (selinux_setup(command_details->selinux_role,
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- command_details->selinux_type, NULL, -1) != 0)
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- debug_return_int(-1);
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if (nfiles < 1)
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debug_return_int(0);
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/* Construct common args for sesh */
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- memcpy(&saved_command_details, command_details, sizeof(struct command_details));
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- command_details->command = _PATH_SUDO_SESH;
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- command_details->flags |= CD_SUDOEDIT_COPY;
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-
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sesh_nargs = 4 + (nfiles * 2) + 1;
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sesh_args = sesh_ap = reallocarray(NULL, sesh_nargs, sizeof(char *));
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if (sesh_args == NULL) {
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@@ -791,6 +817,7 @@ selinux_edit_create_tfiles(struct comman
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*sesh_ap++ = "-h";
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*sesh_ap++ = "0";
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+ /* XXX - temp files should be created with user's context */
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for (i = 0; i < nfiles; i++) {
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char *tfile, *ofile = files[i];
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int tfd;
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@@ -820,8 +847,7 @@ selinux_edit_create_tfiles(struct comman
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*sesh_ap = NULL;
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/* Run sesh -e [-h] 0 <o1> <t1> ... <on> <tn> */
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- command_details->argv = sesh_args;
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- rc = run_command(command_details);
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+ rc = selinux_run_helper(sesh_args, command_details->envp);
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switch (rc) {
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case SESH_SUCCESS:
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break;
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@@ -829,15 +855,12 @@ selinux_edit_create_tfiles(struct comman
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sudo_fatalx(U_("sesh: internal error: odd number of paths"));
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case SESH_ERR_NO_FILES:
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sudo_fatalx(U_("sesh: unable to create temporary files"));
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+ case SESH_ERR_KILLED:
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+ sudo_fatalx(U_("sesh: killed by a signal"));
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default:
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sudo_fatalx(U_("sesh: unknown error %d"), rc);
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}
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- /* Restore saved command_details. */
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- command_details->command = saved_command_details.command;
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- command_details->flags = saved_command_details.flags;
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- command_details->argv = saved_command_details.argv;
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-
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/* Chown to user's UID so they can edit the temporary files. */
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for (i = 0; i < nfiles; i++) {
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if (chown(tf[i].tfile, user_details.uid, user_details.gid) != 0) {
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@@ -858,24 +881,14 @@ selinux_edit_copy_tfiles(struct command_
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{
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char **sesh_args, **sesh_ap;
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int i, rc, sesh_nargs, ret = 1;
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- struct command_details saved_command_details;
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struct timespec ts;
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struct stat sb;
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debug_decl(selinux_edit_copy_tfiles, SUDO_DEBUG_EDIT)
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-
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- /* Prepare selinux stuff (setexeccon) */
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- if (selinux_setup(command_details->selinux_role,
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- command_details->selinux_type, NULL, -1) != 0)
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- debug_return_int(1);
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if (nfiles < 1)
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debug_return_int(0);
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/* Construct common args for sesh */
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- memcpy(&saved_command_details, command_details, sizeof(struct command_details));
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- command_details->command = _PATH_SUDO_SESH;
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- command_details->flags |= CD_SUDOEDIT_COPY;
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-
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sesh_nargs = 3 + (nfiles * 2) + 1;
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sesh_args = sesh_ap = reallocarray(NULL, sesh_nargs, sizeof(char *));
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if (sesh_args == NULL) {
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@@ -913,32 +926,29 @@ selinux_edit_copy_tfiles(struct command_
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if (sesh_ap - sesh_args > 3) {
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/* Run sesh -e 1 <t1> <o1> ... <tn> <on> */
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- command_details->argv = sesh_args;
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- rc = run_command(command_details);
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+ rc = selinux_run_helper(sesh_args, command_details->envp);
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switch (rc) {
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case SESH_SUCCESS:
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ret = 0;
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break;
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case SESH_ERR_NO_FILES:
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sudo_warnx(U_("unable to copy temporary files back to their original location"));
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- sudo_warnx(U_("contents of edit session left in %s"), edit_tmpdir);
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break;
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case SESH_ERR_SOME_FILES:
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sudo_warnx(U_("unable to copy some of the temporary files back to their original location"));
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- sudo_warnx(U_("contents of edit session left in %s"), edit_tmpdir);
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+ break;
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+ case SESH_ERR_KILLED:
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+ sudo_warnx(U_("sesh: killed by a signal"));
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break;
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default:
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sudo_warnx(U_("sesh: unknown error %d"), rc);
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break;
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}
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+ if (ret != 0)
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+ sudo_warnx(U_("contents of edit session left in %s"), edit_tmpdir);
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}
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free(sesh_args);
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- /* Restore saved command_details. */
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- command_details->command = saved_command_details.command;
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- command_details->flags = saved_command_details.flags;
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- command_details->argv = saved_command_details.argv;
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-
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debug_return_int(ret);
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}
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#endif /* HAVE_SELINUX */
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@@ -990,6 +1000,15 @@ sudo_edit(struct command_details *comman
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goto cleanup;
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}
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+#ifdef HAVE_SELINUX
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+ /* Compute new SELinux security context. */
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+ if (ISSET(command_details->flags, CD_RBAC_ENABLED)) {
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+ if (selinux_setup(command_details->selinux_role,
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+ command_details->selinux_type, NULL, -1, false) != 0)
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+ goto cleanup;
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+ }
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+#endif
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+
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/* Copy editor files to temporaries. */
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tf = calloc(nfiles, sizeof(*tf));
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if (tf == NULL) {
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@@ -1025,6 +1044,7 @@ sudo_edit(struct command_details *comman
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/*
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* Run the editor with the invoking user's creds,
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* keeping track of the time spent in the editor.
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+ * XXX - should run editor with user's context
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*/
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if (sudo_gettime_real(×[0]) == -1) {
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sudo_warn(U_("unable to read the clock"));
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diff -up ./src/sudo_exec.h.symbolic-link-attack-3 ./src/sudo_exec.h
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--- ./src/sudo_exec.h.symbolic-link-attack-3 2021-02-02 17:11:32.380020435 +0100
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+++ ./src/sudo_exec.h 2021-02-02 17:11:32.382020407 +0100
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@@ -73,6 +73,7 @@
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*/
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#define SESH_SUCCESS 0 /* successful operation */
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#define SESH_ERR_FAILURE 1 /* unspecified error */
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+#define SESH_ERR_KILLED 2 /* killed by a signal */
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#define SESH_ERR_INVALID 30 /* invalid -e arg value */
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#define SESH_ERR_BAD_PATHS 31 /* odd number of paths */
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#define SESH_ERR_NO_FILES 32 /* copy error, no files copied */
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diff -up ./src/sudo.h.symbolic-link-attack-3 ./src/sudo.h
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--- ./src/sudo.h.symbolic-link-attack-3 2019-10-28 13:28:52.000000000 +0100
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+++ ./src/sudo.h 2021-02-02 17:11:32.382020407 +0100
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@@ -135,12 +135,11 @@ struct user_details {
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#define CD_USE_PTY 0x001000
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#define CD_SET_UTMP 0x002000
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#define CD_EXEC_BG 0x004000
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-#define CD_SUDOEDIT_COPY 0x008000
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-#define CD_SUDOEDIT_FOLLOW 0x010000
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-#define CD_SUDOEDIT_CHECKDIR 0x020000
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-#define CD_SET_GROUPS 0x040000
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-#define CD_LOGIN_SHELL 0x080000
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-#define CD_OVERRIDE_UMASK 0x100000
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+#define CD_SUDOEDIT_FOLLOW 0x008000
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+#define CD_SUDOEDIT_CHECKDIR 0x010000
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+#define CD_SET_GROUPS 0x020000
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+#define CD_LOGIN_SHELL 0x040000
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+#define CD_OVERRIDE_UMASK 0x080000
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struct preserved_fd {
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TAILQ_ENTRY(preserved_fd) entries;
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@@ -240,7 +239,8 @@ int os_init_openbsd(int argc, char *argv
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/* selinux.c */
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int selinux_restore_tty(void);
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int selinux_setup(const char *role, const char *type, const char *ttyn,
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- int ttyfd);
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+ int ttyfd, bool label_tty);
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+int selinux_setcon(void);
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void selinux_execve(int fd, const char *path, char *const argv[],
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char *envp[], bool noexec);
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