Bug fixes and cleanups.

[nss_nonlocal.git] / nonlocal-passwd.c

diff --git a/nonlocal-passwd.c b/nonlocal-passwd.c
index cebc81964c34c84ecfb0bbd10802c30903f779c9..05a06bff53218e480e9800a2fb3d186d9ae1f49e 100644 (file)
--- a/nonlocal-passwd.c
+++ b/nonlocal-passwd.c
@@ -2,7 +2,8 @@
  * nonlocal-passwd.c
  * passwd database for nss_nonlocal proxy.
  *
- * Copyright © 2007 Anders Kaseorg <andersk@mit.edu>
+ * Copyright © 2007 Anders Kaseorg <andersk@mit.edu> and Tim Abbott
+ * <tabbott@mit.edu>
  *
  * Permission is hereby granted, free of charge, to any person
  * obtaining a copy of this software and associated documentation
@@ -42,6 +43,8 @@
 #include "nsswitch-internal.h"
 #include "nonlocal.h"
 
+#define MAGIC_LOCAL_PW_BUFLEN (sysconf(_SC_GETPW_R_SIZE_MAX) + 7)
+
 
 static service_user *
 nss_passwd_nonlocal_database(void)
@@ -54,57 +57,60 @@ nss_passwd_nonlocal_database(void)
 }
 
 
-static __thread int local_only = 0;
-
 enum nss_status
-local_getpwuid_r(uid_t uid, struct passwd *pwd,
-                char *buffer, size_t buflen, int *errnop)
+check_nonlocal_uid(const char *user, uid_t uid, int *errnop)
 {
-    int old_local_only = local_only;
-    int old_errno = errno;
+    enum nss_status status = NSS_STATUS_SUCCESS;
+    struct passwd pwbuf;
+    struct passwd *pwbufp = &pwbuf;
     int ret;
-    errno = *errnop;
-    local_only = 1;
-
-    ret = getpwuid_r(uid, pwd, buffer, buflen, &pwd);
-
-    local_only = old_local_only;
-    *errnop = errno;
-    errno = old_errno;
-
-    if (pwd != NULL)
-       return NSS_STATUS_SUCCESS;
-    else if (ret == 0)
-       return NSS_STATUS_NOTFOUND;
-    else
+    int old_errno = errno;
+    int buflen = MAGIC_LOCAL_PW_BUFLEN;
+    char *buf = malloc(buflen);
+    if (buf == NULL) {
+       *errnop = ENOMEM;
+       errno = old_errno;
        return NSS_STATUS_TRYAGAIN;
+    }
+    errno = 0;
+    ret = getpwuid_r(uid, pwbufp, buf, buflen, &pwbufp);
+    if (ret != 0) {
+       *errnop = errno;
+       status = NSS_STATUS_TRYAGAIN;
+    } else if (pwbufp != NULL) {
+       syslog(LOG_ERR, "nss_nonlocal: possible spoofing attack: non-local user %s has same UID as local user %s!\n", user, pwbuf.pw_name);
+       status = NSS_STATUS_NOTFOUND;
+    }
+    free(buf);
+    errno = old_errno;
+    return status;
 }
 
 enum nss_status
-check_nonlocal_uid(const char *user, uid_t uid, int *errnop)
+check_nonlocal_user(const char *user, int *errnop)
 {
-    struct passwd local_pwd;
-    int local_errno = errno;
-    enum nss_status local_status, status = NSS_STATUS_SUCCESS;
-    int local_buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
-    char *local_buffer = malloc(local_buflen);
-    if (local_buffer == NULL) {
+    enum nss_status status = NSS_STATUS_SUCCESS;
+    struct passwd pwbuf;
+    struct passwd *pwbufp = &pwbuf;
+    int ret;
+    int old_errno = errno;
+    int buflen = MAGIC_LOCAL_PW_BUFLEN;
+    char *buf = malloc(buflen);
+    if (buf == NULL) {
        *errnop = ENOMEM;
-       errno = local_errno;
+       errno = old_errno;
        return NSS_STATUS_TRYAGAIN;
     }
-    local_errno = 0;
-    local_status = local_getpwuid_r(uid, &local_pwd, local_buffer,
-                                   local_buflen, &local_errno);
-    if (local_status == NSS_STATUS_SUCCESS) {
-       syslog(LOG_ERR, "nss_nonlocal: possible spoofing attack: non-local user %s has same UID as local user %s!\n", user, local_pwd.pw_name);
+    errno = 0;
+    ret = getpwnam_r(user, pwbufp, buf, buflen, &pwbufp);
+    if (ret != 0) {
+       *errnop = errno;
+       status = NSS_STATUS_TRYAGAIN;
+    } else if (pwbufp != NULL) {
        status = NSS_STATUS_NOTFOUND;
-    } else if (local_status != NSS_STATUS_NOTFOUND &&
-              local_status != NSS_STATUS_UNAVAIL) {
-       *errnop = local_errno;
-       status = local_status;
     }
-    free(local_buffer);
+    free(buf);
+    errno = old_errno;
     return status;
 }
 
@@ -228,6 +234,9 @@ _nss_nonlocal_getpwnam_r(const char *name, struct passwd *pwd,
     } fct;
     int group_errno;
 
+    if (buflen == MAGIC_LOCAL_PW_BUFLEN)
+       return NSS_STATUS_UNAVAIL;
+
     nip = nss_passwd_nonlocal_database();
     if (nip == NULL)
        return NSS_STATUS_UNAVAIL;
@@ -270,7 +279,7 @@ _nss_nonlocal_getpwuid_r(uid_t uid, struct passwd *pwd,
     } fct;
     int group_errno;
 
-    if (local_only == 1)
+    if (buflen == MAGIC_LOCAL_PW_BUFLEN)
        return NSS_STATUS_UNAVAIL;
 
     nip = nss_passwd_nonlocal_database();