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Diffstat (limited to 'src/suauth.c')
| -rw-r--r-- | src/suauth.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/src/suauth.c b/src/suauth.c new file mode 100644 index 0000000..a5bbe4c --- /dev/null +++ b/src/suauth.c @@ -0,0 +1,239 @@ +/* + * Copyright (c) 1990 - 1994, Julianne Frances Haugh + * Copyright (c) 1996 - 2000, Marek Michałkiewicz + * Copyright (c) 2002 - 2005, Tomasz Kłoczko + * Copyright (c) 2007 - 2008, Nicolas François + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the copyright holders or contributors may not be used to + * endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A + * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include <config.h> +#include <errno.h> +#include <grp.h> +#include <pwd.h> +#include <stdio.h> +#include <sys/types.h> +#include "defines.h" +#include "prototypes.h" + +#ifndef SUAUTHFILE +#define SUAUTHFILE "/etc/suauth" +#endif + +#define NOACTION 0 +#define NOPWORD 1 +#define DENY -1 +#define OWNPWORD 2 + +#ifdef SU_ACCESS + +/* Really, I could do with a few const char's here defining all the + * strings output to the user or the syslog. -- chris + */ +static int applies (const char *, char *); + +static int isgrp (const char *, const char *); + +static int lines = 0; + + +int check_su_auth (const char *actual_id, + const char *wanted_id, + bool su_to_root) +{ + int posn, endline; + const char field[] = ":"; + FILE *authfile_fd; + char temp[1024]; + char *to_users; + char *from_users; + char *action; + + if (!(authfile_fd = fopen (SUAUTHFILE, "r"))) { + int err = errno; + /* + * If the file doesn't exist - default to the standard su + * behaviour (no access control). If open fails for some + * other reason - maybe someone is trying to fool us with + * file descriptors limit etc., so deny access. --marekm + */ + if (ENOENT == err) { + return NOACTION; + } + SYSLOG ((LOG_ERR, + "could not open/read config file '%s': %s\n", + SUAUTHFILE, strerror (err))); + return DENY; + } + + while (fgets (temp, sizeof (temp), authfile_fd) != NULL) { + lines++; + + if (temp[endline = strlen (temp) - 1] != '\n') { + SYSLOG ((LOG_ERR, + "%s, line %d: line too long or missing newline", + SUAUTHFILE, lines)); + continue; + } + + while (endline > 0 && (temp[endline - 1] == ' ' + || temp[endline - 1] == '\t' + || temp[endline - 1] == '\n')) + endline--; + temp[endline] = '\0'; + + posn = 0; + while (temp[posn] == ' ' || temp[posn] == '\t') + posn++; + + if (temp[posn] == '\n' || temp[posn] == '#' + || temp[posn] == '\0') { + continue; + } + if (!(to_users = strtok (temp + posn, field)) + || !(from_users = strtok ((char *) NULL, field)) + || !(action = strtok ((char *) NULL, field)) + || strtok ((char *) NULL, field)) { + SYSLOG ((LOG_ERR, + "%s, line %d. Bad number of fields.\n", + SUAUTHFILE, lines)); + continue; + } + + if (!applies (wanted_id, to_users)) + continue; + if (!applies (actual_id, from_users)) + continue; + if (!strcmp (action, "DENY")) { + SYSLOG ((su_to_root ? LOG_WARN : LOG_NOTICE, + "DENIED su from '%s' to '%s' (%s)\n", + actual_id, wanted_id, SUAUTHFILE)); + fputs (_("Access to su to that account DENIED.\n"), + stderr); + fclose (authfile_fd); + return DENY; + } else if (!strcmp (action, "NOPASS")) { + SYSLOG ((su_to_root ? LOG_NOTICE : LOG_INFO, + "NO password asked for su from '%s' to '%s' (%s)\n", + actual_id, wanted_id, SUAUTHFILE)); + fputs (_("Password authentication bypassed.\n"),stderr); + fclose (authfile_fd); + return NOPWORD; + } else if (!strcmp (action, "OWNPASS")) { + SYSLOG ((su_to_root ? LOG_NOTICE : LOG_INFO, + "su from '%s' to '%s': asking for user's own password (%s)\n", + actual_id, wanted_id, SUAUTHFILE)); + fputs (_("Please enter your OWN password as authentication.\n"), + stderr); + fclose (authfile_fd); + return OWNPWORD; + } else { + SYSLOG ((LOG_ERR, + "%s, line %d: unrecognised action!\n", + SUAUTHFILE, lines)); + } + } + fclose (authfile_fd); + return NOACTION; +} + +static int applies (const char *single, char *list) +{ + const char split[] = ", "; + char *tok; + + int state = 0; + + for (tok = strtok (list, split); tok != NULL; + tok = strtok (NULL, split)) { + + if (!strcmp (tok, "ALL")) { + if (state != 0) { + SYSLOG ((LOG_ERR, + "%s, line %d: ALL in bad place\n", + SUAUTHFILE, lines)); + return 0; + } + state = 1; + } else if (!strcmp (tok, "EXCEPT")) { + if (state != 1) { + SYSLOG ((LOG_ERR, + "%s, line %d: EXCEPT in bas place\n", + SUAUTHFILE, lines)); + return 0; + } + state = 2; + } else if (!strcmp (tok, "GROUP")) { + if ((state != 0) && (state != 2)) { + SYSLOG ((LOG_ERR, + "%s, line %d: GROUP in bad place\n", + SUAUTHFILE, lines)); + return 0; + } + state = (state == 0) ? 3 : 4; + } else { + switch (state) { + case 0: /* No control words yet */ + if (!strcmp (tok, single)) + return 1; + break; + case 1: /* An all */ + SYSLOG ((LOG_ERR, + "%s, line %d: expect another token after ALL\n", + SUAUTHFILE, lines)); + return 0; + case 2: /* All except */ + if (!strcmp (tok, single)) + return 0; + break; + case 3: /* Group */ + if (isgrp (single, tok)) + return 1; + break; + case 4: /* All except group */ + if (isgrp (single, tok)) + return 0; + /* FALL THRU */ + } + } + } + if ((state != 0) && (state != 3)) + return 1; + return 0; +} + +static int isgrp (const char *name, const char *group) +{ + struct group *grp; + + grp = getgrnam (group); /* local, no need for xgetgrnam */ + + if (!grp || !grp->gr_mem) + return 0; + + return is_on_list (grp->gr_mem, name); +} +#endif /* SU_ACCESS */ |