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-rw-r--r--usr.bin/doas/env.c235
1 files changed, 235 insertions, 0 deletions
diff --git a/usr.bin/doas/env.c b/usr.bin/doas/env.c
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+++ b/usr.bin/doas/env.c
@@ -0,0 +1,235 @@
+/* $OpenBSD: env.c,v 1.10 2019/07/07 19:21:28 tedu Exp $ */
+/*
+ * Copyright (c) 2016 Ted Unangst <tedu@openbsd.org>
+ *
+ * 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.
+ */
+
+#include <sys/types.h>
+#include <sys/tree.h>
+
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <err.h>
+#include <unistd.h>
+#include <errno.h>
+#include <pwd.h>
+
+#include "doas.h"
+
+const char *formerpath;
+
+struct envnode {
+ RB_ENTRY(envnode) node;
+ const char *key;
+ const char *value;
+};
+
+struct env {
+ RB_HEAD(envtree, envnode) root;
+ u_int count;
+};
+
+static void fillenv(struct env *env, const char **envlist);
+
+static int
+envcmp(struct envnode *a, struct envnode *b)
+{
+ return strcmp(a->key, b->key);
+}
+RB_GENERATE_STATIC(envtree, envnode, node, envcmp)
+
+static struct envnode *
+createnode(const char *key, const char *value)
+{
+ struct envnode *node;
+
+ node = malloc(sizeof(*node));
+ if (!node)
+ err(1, NULL);
+ node->key = strdup(key);
+ node->value = strdup(value);
+ if (!node->key || !node->value)
+ err(1, NULL);
+ return node;
+}
+
+static void
+freenode(struct envnode *node)
+{
+ free((char *)node->key);
+ free((char *)node->value);
+ free(node);
+}
+
+static void
+addnode(struct env *env, const char *key, const char *value)
+{
+ struct envnode *node;
+
+ node = createnode(key, value);
+ RB_INSERT(envtree, &env->root, node);
+ env->count++;
+}
+
+static struct env *
+createenv(const struct rule *rule, const struct passwd *mypw,
+ const struct passwd *targpw)
+{
+ static const char *copyset[] = {
+ "DISPLAY", "TERM",
+ NULL
+ };
+ struct env *env;
+ u_int i;
+
+ env = malloc(sizeof(*env));
+ if (!env)
+ err(1, NULL);
+ RB_INIT(&env->root);
+ env->count = 0;
+
+ addnode(env, "DOAS_USER", mypw->pw_name);
+ addnode(env, "HOME", targpw->pw_dir);
+ addnode(env, "LOGNAME", targpw->pw_name);
+ addnode(env, "PATH", getenv("PATH"));
+ addnode(env, "SHELL", targpw->pw_shell);
+ addnode(env, "USER", targpw->pw_name);
+
+ fillenv(env, copyset);
+
+ if (rule->options & KEEPENV) {
+ extern const char **environ;
+
+ for (i = 0; environ[i] != NULL; i++) {
+ struct envnode *node;
+ const char *e, *eq;
+ size_t len;
+ char name[1024];
+
+ e = environ[i];
+
+ /* ignore invalid or overlong names */
+ if ((eq = strchr(e, '=')) == NULL || eq == e)
+ continue;
+ len = eq - e;
+ if (len > sizeof(name) - 1)
+ continue;
+ memcpy(name, e, len);
+ name[len] = '\0';
+
+ node = createnode(name, eq + 1);
+ if (RB_INSERT(envtree, &env->root, node)) {
+ /* ignore any later duplicates */
+ freenode(node);
+ } else {
+ env->count++;
+ }
+ }
+ }
+
+ return env;
+}
+
+static char **
+flattenenv(struct env *env)
+{
+ char **envp;
+ struct envnode *node;
+ u_int i;
+
+ envp = reallocarray(NULL, env->count + 1, sizeof(char *));
+ if (!envp)
+ err(1, NULL);
+ i = 0;
+ RB_FOREACH(node, envtree, &env->root) {
+ if (asprintf(&envp[i], "%s=%s", node->key, node->value) == -1)
+ err(1, NULL);
+ i++;
+ }
+ envp[i] = NULL;
+ return envp;
+}
+
+static void
+fillenv(struct env *env, const char **envlist)
+{
+ struct envnode *node, key;
+ const char *e, *eq;
+ const char *val;
+ char name[1024];
+ u_int i;
+ size_t len;
+
+ for (i = 0; envlist[i]; i++) {
+ e = envlist[i];
+
+ /* parse out env name */
+ if ((eq = strchr(e, '=')) == NULL)
+ len = strlen(e);
+ else
+ len = eq - e;
+ if (len > sizeof(name) - 1)
+ continue;
+ memcpy(name, e, len);
+ name[len] = '\0';
+
+ /* delete previous copies */
+ key.key = name;
+ if (*name == '-')
+ key.key = name + 1;
+ if ((node = RB_FIND(envtree, &env->root, &key))) {
+ RB_REMOVE(envtree, &env->root, node);
+ freenode(node);
+ env->count--;
+ }
+ if (*name == '-')
+ continue;
+
+ /* assign value or inherit from environ */
+ if (eq) {
+ val = eq + 1;
+ if (*val == '$') {
+ if (strcmp(val + 1, "PATH") == 0)
+ val = formerpath;
+ else
+ val = getenv(val + 1);
+ }
+ } else {
+ if (strcmp(name, "PATH") == 0)
+ val = formerpath;
+ else
+ val = getenv(name);
+ }
+ /* at last, we have something to insert */
+ if (val) {
+ node = createnode(name, val);
+ RB_INSERT(envtree, &env->root, node);
+ env->count++;
+ }
+ }
+}
+
+char **
+prepenv(const struct rule *rule, const struct passwd *mypw,
+ const struct passwd *targpw)
+{
+ struct env *env;
+
+ env = createenv(rule, mypw, targpw);
+ if (rule->envlist)
+ fillenv(env, rule->envlist);
+
+ return flattenenv(env);
+}