diff options
Diffstat (limited to 'plugins/sudoers/editor.c')
| -rw-r--r-- | plugins/sudoers/editor.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/plugins/sudoers/editor.c b/plugins/sudoers/editor.c new file mode 100644 index 0000000..ec8e7b0 --- /dev/null +++ b/plugins/sudoers/editor.c @@ -0,0 +1,179 @@ +/* + * Copyright (c) 2010-2015 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 <sys/stat.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 "sudoers.h" + +/* + * Search for the specified editor in the user's PATH, checking + * the result against whitelist if non-NULL. An argument vector + * suitable for execve() is allocated and stored in argv_out. + * If nfiles is non-zero, files[] is added to the end of argv_out. + * + * Returns the path to be executed on success, else NULL. + * The caller is responsible for freeing the returned editor path + * as well as the argument vector. + */ +static char * +resolve_editor(const char *ed, size_t edlen, int nfiles, char **files, + int *argc_out, char ***argv_out, char * const *whitelist) +{ + char **nargv, *editor, *editor_path = NULL; + const char *cp, *ep, *tmp; + const char *edend = ed + edlen; + struct stat user_editor_sb; + int nargc; + debug_decl(resolve_editor, SUDOERS_DEBUG_UTIL) + + /* + * Split editor into an argument vector, including files to edit. + * The EDITOR and VISUAL environment variables may contain command + * line args so look for those and alloc space for them too. + */ + cp = sudo_strsplit(ed, edend, " \t", &ep); + if (cp == NULL) + debug_return_str(NULL); + editor = strndup(cp, (size_t)(ep - cp)); + if (editor == NULL) { + sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory")); + debug_return_str(NULL); + } + + /* If we can't find the editor in the user's PATH, give up. */ + if (find_path(editor, &editor_path, &user_editor_sb, getenv("PATH"), 0, whitelist) != FOUND) { + free(editor); + errno = ENOENT; + debug_return_str(NULL); + } + + /* Count rest of arguments and allocate editor argv. */ + for (nargc = 1, tmp = ep; sudo_strsplit(NULL, edend, " \t", &tmp) != NULL; ) + nargc++; + if (nfiles != 0) + nargc += nfiles + 1; + nargv = reallocarray(NULL, nargc + 1, sizeof(char *)); + if (nargv == NULL) { + sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory")); + free(editor); + free(editor_path); + debug_return_str(NULL); + } + + /* Fill in editor argv (assumes files[] is NULL-terminated). */ + nargv[0] = editor; + for (nargc = 1; (cp = sudo_strsplit(NULL, edend, " \t", &ep)) != NULL; nargc++) { + nargv[nargc] = strndup(cp, (size_t)(ep - cp)); + if (nargv[nargc] == NULL) { + sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory")); + free(editor_path); + while (nargc--) + free(nargv[nargc]); + free(nargv); + debug_return_str(NULL); + } + } + if (nfiles != 0) { + nargv[nargc++] = "--"; + while (nfiles--) + nargv[nargc++] = *files++; + } + nargv[nargc] = NULL; + + *argc_out = nargc; + *argv_out = nargv; + debug_return_str(editor_path); +} + +/* + * Determine which editor to use based on the SUDO_EDITOR, VISUAL and + * EDITOR environment variables as well as the editor path in sudoers. + * If env_error is true, an editor environment variable that cannot be + * resolved is an error. + * + * Returns the path to be executed on success, else NULL. + * The caller is responsible for freeing the returned editor path + * as well as the argument vector. + */ +char * +find_editor(int nfiles, char **files, int *argc_out, char ***argv_out, + char * const *whitelist, const char **env_editor, bool env_error) +{ + char *ev[3], *editor_path = NULL; + unsigned int i; + debug_decl(find_editor, SUDOERS_DEBUG_UTIL) + + /* + * If any of SUDO_EDITOR, VISUAL or EDITOR are set, choose the first one. + */ + *env_editor = NULL; + ev[0] = "SUDO_EDITOR"; + ev[1] = "VISUAL"; + ev[2] = "EDITOR"; + for (i = 0; i < nitems(ev); i++) { + char *editor = getenv(ev[i]); + + if (editor != NULL && *editor != '\0') { + *env_editor = editor; + editor_path = resolve_editor(editor, strlen(editor), + nfiles, files, argc_out, argv_out, whitelist); + if (editor_path != NULL) + break; + if (errno != ENOENT) + debug_return_str(NULL); + } + } + if (editor_path == NULL) { + const char *def_editor_end = def_editor + strlen(def_editor); + const char *cp, *ep; + + if (env_error && *env_editor != NULL) { + /* User-specified editor could not be found. */ + debug_return_str(NULL); + } + + /* def_editor could be a path, split it up, avoiding strtok() */ + for (cp = sudo_strsplit(def_editor, def_editor_end, ":", &ep); + cp != NULL; cp = sudo_strsplit(NULL, def_editor_end, ":", &ep)) { + editor_path = resolve_editor(cp, (size_t)(ep - cp), nfiles, + files, argc_out, argv_out, whitelist); + if (editor_path != NULL) + break; + if (errno != ENOENT) + debug_return_str(NULL); + } + } + + debug_return_str(editor_path); +} |