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Diffstat (limited to '')
| -rw-r--r-- | src/hooks.c | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/src/hooks.c b/src/hooks.c new file mode 100644 index 0000000..1216980 --- /dev/null +++ b/src/hooks.c @@ -0,0 +1,251 @@ +/* + * Copyright (c) 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 <unistd.h> +#include <errno.h> + +#include "sudo.h" +#include "sudo_plugin.h" +#include "sudo_plugin_int.h" + +/* Singly linked hook list. */ +struct sudo_hook_entry { + SLIST_ENTRY(sudo_hook_entry) entries; + union { + sudo_hook_fn_t generic_fn; + sudo_hook_fn_setenv_t setenv_fn; + sudo_hook_fn_unsetenv_t unsetenv_fn; + sudo_hook_fn_getenv_t getenv_fn; + sudo_hook_fn_putenv_t putenv_fn; + } u; + void *closure; +}; +SLIST_HEAD(sudo_hook_list, sudo_hook_entry); + +/* Each hook type gets own hook list. */ +static struct sudo_hook_list sudo_hook_setenv_list = + SLIST_HEAD_INITIALIZER(sudo_hook_setenv_list); +static struct sudo_hook_list sudo_hook_unsetenv_list = + SLIST_HEAD_INITIALIZER(sudo_hook_unsetenv_list); +static struct sudo_hook_list sudo_hook_getenv_list = + SLIST_HEAD_INITIALIZER(sudo_hook_getenv_list); +static struct sudo_hook_list sudo_hook_putenv_list = + SLIST_HEAD_INITIALIZER(sudo_hook_putenv_list); + +/* NOTE: must not anything that might call setenv() */ +int +process_hooks_setenv(const char *name, const char *value, int overwrite) +{ + struct sudo_hook_entry *hook; + int rc = SUDO_HOOK_RET_NEXT; + + /* First process the hooks. */ + SLIST_FOREACH(hook, &sudo_hook_setenv_list, entries) { + rc = hook->u.setenv_fn(name, value, overwrite, hook->closure); + if (rc == SUDO_HOOK_RET_STOP || rc == SUDO_HOOK_RET_ERROR) + break; + } + return rc; +} + +/* NOTE: must not anything that might call putenv() */ +int +process_hooks_putenv(char *string) +{ + struct sudo_hook_entry *hook; + int rc = SUDO_HOOK_RET_NEXT; + + /* First process the hooks. */ + SLIST_FOREACH(hook, &sudo_hook_putenv_list, entries) { + rc = hook->u.putenv_fn(string, hook->closure); + if (rc == SUDO_HOOK_RET_STOP || rc == SUDO_HOOK_RET_ERROR) + break; + } + return rc; +} + +/* NOTE: must not anything that might call getenv() */ +int +process_hooks_getenv(const char *name, char **value) +{ + struct sudo_hook_entry *hook; + char *val = NULL; + int rc = SUDO_HOOK_RET_NEXT; + + /* First process the hooks. */ + SLIST_FOREACH(hook, &sudo_hook_getenv_list, entries) { + rc = hook->u.getenv_fn(name, &val, hook->closure); + if (rc == SUDO_HOOK_RET_STOP || rc == SUDO_HOOK_RET_ERROR) + break; + } + if (val != NULL) + *value = val; + return rc; +} + +/* NOTE: must not anything that might call unsetenv() */ +int +process_hooks_unsetenv(const char *name) +{ + struct sudo_hook_entry *hook; + int rc = SUDO_HOOK_RET_NEXT; + + /* First process the hooks. */ + SLIST_FOREACH(hook, &sudo_hook_unsetenv_list, entries) { + rc = hook->u.unsetenv_fn(name, hook->closure); + if (rc == SUDO_HOOK_RET_STOP || rc == SUDO_HOOK_RET_ERROR) + break; + } + return rc; +} + +/* Hook registration internals. */ +static int +register_hook_internal(struct sudo_hook_list *head, + int (*hook_fn)(), void *closure) +{ + struct sudo_hook_entry *hook; + debug_decl(register_hook_internal, SUDO_DEBUG_HOOKS) + + if ((hook = calloc(1, sizeof(*hook))) == NULL) { + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO, + "unable to allocate memory"); + debug_return_int(-1); + } + hook->u.generic_fn = hook_fn; + hook->closure = closure; + SLIST_INSERT_HEAD(head, hook, entries); + + debug_return_int(0); +} + +/* Register the specified hook. */ +int +register_hook(struct sudo_hook *hook) +{ + int ret; + debug_decl(register_hook, SUDO_DEBUG_HOOKS) + + if (SUDO_API_VERSION_GET_MAJOR(hook->hook_version) != SUDO_HOOK_VERSION_MAJOR) { + /* Major versions must match. */ + errno = EINVAL; + ret = -1; + } else { + switch (hook->hook_type) { + case SUDO_HOOK_GETENV: + ret = register_hook_internal(&sudo_hook_getenv_list, + hook->hook_fn, hook->closure); + break; + case SUDO_HOOK_PUTENV: + ret = register_hook_internal(&sudo_hook_putenv_list, + hook->hook_fn, hook->closure); + break; + case SUDO_HOOK_SETENV: + ret = register_hook_internal(&sudo_hook_setenv_list, + hook->hook_fn, hook->closure); + break; + case SUDO_HOOK_UNSETENV: + ret = register_hook_internal(&sudo_hook_unsetenv_list, + hook->hook_fn, hook->closure); + break; + default: + /* XXX - use define for unknown value */ + errno = ENOTSUP; + ret = 1; + break; + } + } + + debug_return_int(ret); +} + +/* Hook deregistration internals. */ +static void +deregister_hook_internal(struct sudo_hook_list *head, + int (*hook_fn)(), void *closure) +{ + struct sudo_hook_entry *hook, *prev = NULL; + debug_decl(deregister_hook_internal, SUDO_DEBUG_HOOKS) + + SLIST_FOREACH(hook, head, entries) { + if (hook->u.generic_fn == hook_fn && hook->closure == closure) { + /* Remove from list and free. */ + if (prev == NULL) + SLIST_REMOVE_HEAD(head, entries); + else + SLIST_REMOVE_AFTER(prev, entries); + free(hook); + break; + } + prev = hook; + } + + debug_return; +} + +/* Deregister the specified hook. */ +int +deregister_hook(struct sudo_hook *hook) +{ + int ret = 0; + debug_decl(deregister_hook, SUDO_DEBUG_HOOKS) + + if (SUDO_API_VERSION_GET_MAJOR(hook->hook_version) != SUDO_HOOK_VERSION_MAJOR) { + /* Major versions must match. */ + ret = -1; + } else { + switch (hook->hook_type) { + case SUDO_HOOK_GETENV: + deregister_hook_internal(&sudo_hook_getenv_list, hook->hook_fn, + hook->closure); + break; + case SUDO_HOOK_PUTENV: + deregister_hook_internal(&sudo_hook_putenv_list, hook->hook_fn, + hook->closure); + break; + case SUDO_HOOK_SETENV: + deregister_hook_internal(&sudo_hook_setenv_list, hook->hook_fn, + hook->closure); + break; + case SUDO_HOOK_UNSETENV: + deregister_hook_internal(&sudo_hook_unsetenv_list, hook->hook_fn, + hook->closure); + break; + default: + /* XXX - use define for unknown value */ + ret = 1; + break; + } + } + + debug_return_int(ret); +} |