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-rw-r--r--src/env_hooks.c297
1 files changed, 297 insertions, 0 deletions
diff --git a/src/env_hooks.c b/src/env_hooks.c
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+++ b/src/env_hooks.c
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+/*
+ * Copyright (c) 2010, 2012-2016 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * 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 <config.h>
+
+#include <sys/types.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef HAVE_STRING_H
+# include <string.h>
+#endif /* HAVE_STRING_H */
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif /* HAVE_STRINGS_H */
+#include <errno.h>
+
+#include "sudo.h"
+#include "sudo_plugin.h"
+#include "sudo_dso.h"
+
+extern char **environ; /* global environment pointer */
+static char **priv_environ; /* private environment pointer */
+
+/*
+ * NOTE: we don't use dlsym() to find the libc getenv()
+ * since this may allocate memory on some systems (glibc)
+ * which leads to a hang if malloc() calls getenv (jemalloc).
+ */
+char *
+getenv_unhooked(const char *name)
+{
+ char **ep, *val = NULL;
+ size_t namelen = 0;
+
+ /* For BSD compatibility, treat '=' in name like end of string. */
+ while (name[namelen] != '\0' && name[namelen] != '=')
+ namelen++;
+ for (ep = environ; *ep != NULL; ep++) {
+ if (strncmp(*ep, name, namelen) == 0 && (*ep)[namelen] == '=') {
+ val = *ep + namelen + 1;
+ break;
+ }
+ }
+ return val;
+}
+
+__dso_public char *
+getenv(const char *name)
+{
+ char *val = NULL;
+
+ switch (process_hooks_getenv(name, &val)) {
+ case SUDO_HOOK_RET_STOP:
+ return val;
+ case SUDO_HOOK_RET_ERROR:
+ return NULL;
+ default:
+ return getenv_unhooked(name);
+ }
+}
+
+static int
+rpl_putenv(PUTENV_CONST char *string)
+{
+ char **ep;
+ size_t len;
+ bool found = false;
+
+ /* Look for existing entry. */
+ len = (strchr(string, '=') - string) + 1;
+ for (ep = environ; *ep != NULL; ep++) {
+ if (strncmp(string, *ep, len) == 0) {
+ *ep = (char *)string;
+ found = true;
+ break;
+ }
+ }
+ /* Prune out duplicate variables. */
+ if (found) {
+ while (*ep != NULL) {
+ if (strncmp(string, *ep, len) == 0) {
+ char **cur = ep;
+ while ((*cur = *(cur + 1)) != NULL)
+ cur++;
+ } else {
+ ep++;
+ }
+ }
+ }
+
+ /* Append at the end if not already found. */
+ if (!found) {
+ size_t env_len = (size_t)(ep - environ);
+ char **envp = reallocarray(priv_environ, env_len + 2, sizeof(char *));
+ if (envp == NULL)
+ return -1;
+ if (environ != priv_environ)
+ memcpy(envp, environ, env_len * sizeof(char *));
+ envp[env_len++] = (char *)string;
+ envp[env_len] = NULL;
+ priv_environ = environ = envp;
+ }
+ return 0;
+}
+
+typedef int (*sudo_fn_putenv_t)(PUTENV_CONST char *);
+
+static int
+putenv_unhooked(PUTENV_CONST char *string)
+{
+ sudo_fn_putenv_t fn;
+
+ fn = (sudo_fn_putenv_t)sudo_dso_findsym(SUDO_DSO_NEXT, "putenv");
+ if (fn != NULL)
+ return fn(string);
+ return rpl_putenv(string);
+}
+
+__dso_public int
+putenv(PUTENV_CONST char *string)
+{
+ switch (process_hooks_putenv((char *)string)) {
+ case SUDO_HOOK_RET_STOP:
+ return 0;
+ case SUDO_HOOK_RET_ERROR:
+ return -1;
+ default:
+ return putenv_unhooked(string);
+ }
+}
+
+static int
+rpl_setenv(const char *var, const char *val, int overwrite)
+{
+ char *envstr, *dst;
+ const char *src;
+ size_t esize;
+
+ if (!var || *var == '\0') {
+ errno = EINVAL;
+ return -1;
+ }
+
+ /*
+ * POSIX says a var name with '=' is an error but BSD
+ * just ignores the '=' and anything after it.
+ */
+ for (src = var; *src != '\0' && *src != '='; src++)
+ continue;
+ esize = (size_t)(src - var) + 2;
+ if (val) {
+ esize += strlen(val); /* glibc treats a NULL val as "" */
+ }
+
+ /* Allocate and fill in envstr. */
+ if ((envstr = malloc(esize)) == NULL)
+ return -1;
+ for (src = var, dst = envstr; *src != '\0' && *src != '=';)
+ *dst++ = *src++;
+ *dst++ = '=';
+ if (val) {
+ for (src = val; *src != '\0';)
+ *dst++ = *src++;
+ }
+ *dst = '\0';
+
+ if (!overwrite && getenv(var) != NULL) {
+ free(envstr);
+ return 0;
+ }
+ if (rpl_putenv(envstr) == -1) {
+ free(envstr);
+ return -1;
+ }
+ return 0;
+}
+
+typedef int (*sudo_fn_setenv_t)(const char *, const char *, int);
+
+static int
+setenv_unhooked(const char *var, const char *val, int overwrite)
+{
+ sudo_fn_setenv_t fn;
+
+ fn = (sudo_fn_setenv_t)sudo_dso_findsym(SUDO_DSO_NEXT, "setenv");
+ if (fn != NULL)
+ return fn(var, val, overwrite);
+ return rpl_setenv(var, val, overwrite);
+}
+
+__dso_public int
+setenv(const char *var, const char *val, int overwrite)
+{
+ switch (process_hooks_setenv(var, val, overwrite)) {
+ case SUDO_HOOK_RET_STOP:
+ return 0;
+ case SUDO_HOOK_RET_ERROR:
+ return -1;
+ default:
+ return setenv_unhooked(var, val, overwrite);
+ }
+}
+
+static int
+rpl_unsetenv(const char *var)
+{
+ char **ep = environ;
+ size_t len;
+
+ if (var == NULL || *var == '\0' || strchr(var, '=') != NULL) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ len = strlen(var);
+ while (*ep != NULL) {
+ if (strncmp(var, *ep, len) == 0 && (*ep)[len] == '=') {
+ /* Found it; shift remainder + NULL over by one. */
+ char **cur = ep;
+ while ((*cur = *(cur + 1)) != NULL)
+ cur++;
+ /* Keep going, could be multiple instances of the var. */
+ } else {
+ ep++;
+ }
+ }
+ return 0;
+}
+
+#ifdef UNSETENV_VOID
+typedef void (*sudo_fn_unsetenv_t)(const char *);
+#else
+typedef int (*sudo_fn_unsetenv_t)(const char *);
+#endif
+
+static int
+unsetenv_unhooked(const char *var)
+{
+ int ret = 0;
+ sudo_fn_unsetenv_t fn;
+
+ fn = (sudo_fn_unsetenv_t)sudo_dso_findsym(SUDO_DSO_NEXT, "unsetenv");
+ if (fn != NULL) {
+# ifdef UNSETENV_VOID
+ fn(var);
+# else
+ ret = fn(var);
+# endif
+ } else {
+ ret = rpl_unsetenv(var);
+ }
+ return ret;
+}
+
+#ifdef UNSETENV_VOID
+__dso_public void
+#else
+__dso_public int
+#endif
+unsetenv(const char *var)
+{
+ int ret;
+
+ switch (process_hooks_unsetenv(var)) {
+ case SUDO_HOOK_RET_STOP:
+ ret = 0;
+ break;
+ case SUDO_HOOK_RET_ERROR:
+ ret = -1;
+ break;
+ default:
+ ret = unsetenv_unhooked(var);
+ break;
+ }
+#ifndef UNSETENV_VOID
+ return ret;
+#endif
+}
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