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/*
* 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);
}
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