X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/c8445989f9005acc20e4a123673a93fb3cc57ead..1836f69f0538fd8f9ecdad854e2fd6ed9990546f:/auth.c?ds=sidebyside diff --git a/auth.c b/auth.c index 07e5b8f0..62c184dd 100644 --- a/auth.c +++ b/auth.c @@ -23,7 +23,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: auth.c,v 1.22 2001/05/20 17:20:35 markus Exp $"); +RCSID("$OpenBSD: auth.c,v 1.38 2002/03/18 03:41:08 provos Exp $"); #ifdef HAVE_LOGIN_H #include @@ -32,7 +32,9 @@ RCSID("$OpenBSD: auth.c,v 1.22 2001/05/20 17:20:35 markus Exp $"); #include #endif /* defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) */ +#ifdef HAVE_LIBGEN_H #include +#endif #include "xmalloc.h" #include "match.h" @@ -44,6 +46,8 @@ RCSID("$OpenBSD: auth.c,v 1.22 2001/05/20 17:20:35 markus Exp $"); #include "canohost.h" #include "buffer.h" #include "bufaux.h" +#include "uidswap.h" +#include "tildexpand.h" /* import */ extern ServerOptions options; @@ -61,6 +65,7 @@ int allowed_user(struct passwd * pw) { struct stat st; + const char *hostname = NULL, *ipaddr = NULL; char *shell; int i; #ifdef WITH_AIXAUTHENTICATE @@ -100,36 +105,61 @@ allowed_user(struct passwd * pw) shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; /* deny if shell does not exists or is not executable */ - if (stat(shell, &st) != 0) + if (stat(shell, &st) != 0) { + log("User %.100s not allowed because shell %.100s does not exist", + pw->pw_name, shell); return 0; - if (!((st.st_mode & S_IFREG) && (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)))) + } + if (S_ISREG(st.st_mode) == 0 || + (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) { + log("User %.100s not allowed because shell %.100s is not executable", + pw->pw_name, shell); return 0; + } + + if (options.num_deny_users > 0 || options.num_allow_users > 0) { + hostname = get_canonical_hostname(options.verify_reverse_mapping); + ipaddr = get_remote_ipaddr(); + } /* Return false if user is listed in DenyUsers */ if (options.num_deny_users > 0) { for (i = 0; i < options.num_deny_users; i++) - if (match_pattern(pw->pw_name, options.deny_users[i])) + if (match_user(pw->pw_name, hostname, ipaddr, + options.deny_users[i])) { + log("User %.100s not allowed because listed in DenyUsers", + pw->pw_name); return 0; + } } /* Return false if AllowUsers isn't empty and user isn't listed there */ if (options.num_allow_users > 0) { for (i = 0; i < options.num_allow_users; i++) - if (match_pattern(pw->pw_name, options.allow_users[i])) + if (match_user(pw->pw_name, hostname, ipaddr, + options.allow_users[i])) break; /* i < options.num_allow_users iff we break for loop */ - if (i >= options.num_allow_users) + if (i >= options.num_allow_users) { + log("User %.100s not allowed because not listed in AllowUsers", + pw->pw_name); return 0; + } } if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { /* Get the user's group access list (primary and supplementary) */ - if (ga_init(pw->pw_name, pw->pw_gid) == 0) + if (ga_init(pw->pw_name, pw->pw_gid) == 0) { + log("User %.100s not allowed because not in any group", + pw->pw_name); return 0; + } /* Return false if one of user's groups is listed in DenyGroups */ if (options.num_deny_groups > 0) if (ga_match(options.deny_groups, options.num_deny_groups)) { ga_free(); + log("User %.100s not allowed because a group is listed in DenyGroups", + pw->pw_name); return 0; } /* @@ -140,6 +170,8 @@ allowed_user(struct passwd * pw) if (!ga_match(options.allow_groups, options.num_allow_groups)) { ga_free(); + log("User %.100s not allowed because none of user's groups are listed in AllowGroups", + pw->pw_name); return 0; } ga_free(); @@ -196,7 +228,7 @@ auth_log(Authctxt *authctxt, int authenticated, char *method, char *info) authmsg, method, authctxt->valid ? "" : "illegal user ", - authctxt->valid && authctxt->pw->pw_uid == 0 ? "ROOT" : authctxt->user, + authctxt->user, get_remote_ipaddr(), get_remote_port(), info); @@ -260,7 +292,7 @@ expand_filename(const char *filename, struct passwd *pw) } if (cp[0] == '%' && cp[1] == 'u') { buffer_append(&buffer, pw->pw_name, - strlen(pw->pw_name)); + strlen(pw->pw_name)); cp++; continue; } @@ -295,10 +327,49 @@ authorized_keys_file2(struct passwd *pw) return expand_filename(options.authorized_keys_file2, pw); } +/* return ok if key exists in sysfile or userfile */ +HostStatus +check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host, + const char *sysfile, const char *userfile) +{ + Key *found; + char *user_hostfile; + struct stat st; + HostStatus host_status; + + /* Check if we know the host and its host key. */ + found = key_new(key->type); + host_status = check_host_in_hostfile(sysfile, host, key, found, NULL); + + if (host_status != HOST_OK && userfile != NULL) { + user_hostfile = tilde_expand_filename(userfile, pw->pw_uid); + if (options.strict_modes && + (stat(user_hostfile, &st) == 0) && + ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || + (st.st_mode & 022) != 0)) { + log("Authentication refused for %.100s: " + "bad owner or modes for %.200s", + pw->pw_name, user_hostfile); + } else { + temporarily_use_uid(pw); + host_status = check_host_in_hostfile(user_hostfile, + host, key, found, NULL); + restore_uid(); + } + xfree(user_hostfile); + } + key_free(found); + + debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ? + "ok" : "not found", host); + return host_status; +} + + /* * Check a given file for security. This is defined as all components * of the path to the file must either be owned by either the owner of - * of the file or root and no directories must be world writable. + * of the file or root and no directories must be group or world writable. * * XXX Should any specific check be done for sym links ? * @@ -308,9 +379,11 @@ authorized_keys_file2(struct passwd *pw) * Returns 0 on success and -1 on failure */ int -secure_filename(FILE *f, const char *file, uid_t uid, char *err, size_t errlen) +secure_filename(FILE *f, const char *file, struct passwd *pw, + char *err, size_t errlen) { - char buf[MAXPATHLEN]; + uid_t uid = pw->pw_uid; + char buf[MAXPATHLEN], homedir[MAXPATHLEN]; char *cp; struct stat st; @@ -319,6 +392,11 @@ secure_filename(FILE *f, const char *file, uid_t uid, char *err, size_t errlen) strerror(errno)); return -1; } + if (realpath(pw->pw_dir, homedir) == NULL) { + snprintf(err, errlen, "realpath %s failed: %s", pw->pw_dir, + strerror(errno)); + return -1; + } /* check the open file to avoid races */ if (fstat(fileno(f), &st) < 0 || @@ -341,11 +419,17 @@ secure_filename(FILE *f, const char *file, uid_t uid, char *err, size_t errlen) if (stat(buf, &st) < 0 || (st.st_uid != 0 && st.st_uid != uid) || (st.st_mode & 022) != 0) { - snprintf(err, errlen, + snprintf(err, errlen, "bad ownership or modes for directory %s", buf); return -1; } + /* If are passed the homedir then we can stop */ + if (strcmp(homedir, buf) == 0) { + debug3("secure_filename: terminating check at '%s'", + buf); + break; + } /* * dirname should always complete with a "/" path, * but we can be paranoid and check for "." too @@ -355,3 +439,35 @@ secure_filename(FILE *f, const char *file, uid_t uid, char *err, size_t errlen) } return 0; } + +struct passwd * +getpwnamallow(const char *user) +{ +#ifdef HAVE_LOGIN_CAP + extern login_cap_t *lc; +#ifdef BSD_AUTH + auth_session_t *as; +#endif +#endif + struct passwd *pw; + + pw = getpwnam(user); + if (pw == NULL || !allowed_user(pw)) + return (NULL); +#ifdef HAVE_LOGIN_CAP + if ((lc = login_getclass(pw->pw_class)) == NULL) { + debug("unable to get login class: %s", user); + return (NULL); + } +#ifdef BSD_AUTH + if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 || + auth_approval(NULL, lc, pw->pw_name, "ssh") <= 0) { + debug("Approval failure for %s", user); + pw = NULL; + } + if (as != NULL) + auth_close(as); +#endif +#endif + return (pw); +}