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validate checks against system users

Greg Wiley authored on 06/04/2017 22:10:16
Showing 3 changed files
test_support.h
History View file @ cb40315
... ... 
@@ -4,19 +4,27 @@
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 #ifndef _TEST_SUPPORT_H
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 #define _TEST_SUPPORT_H
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+#include <stdlib.h>
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+// SYSLOG
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 void fake_openlog(const char *ident, int logopt, int facility);
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 void fake_syslog(int priority, const char *format, ...);
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 void fake_closelog(void);
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-/*
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- * replace C library functions with fake counterparts when UINT_TEST symbol
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- * is defined
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- */
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+// PWD
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+struct passwd;
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+int fake_getpwnam_r(const char *nam, struct passwd *pwd, char *buffer, size_t bufsize, struct passwd **result);
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+
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+
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 #ifdef UNIT_TEST
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+// SYSLOG
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 #define openlog(IDENT, LOGOPT, FACILITY) fake_openlog(IDENT, LOGOPT, FACILITY)
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 #define syslog(PRIORITY, ...) fake_syslog(PRIORITY, __VA_ARGS__)
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 #define closelog() fake_closelog()
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+
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+// PWD
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+#define getpwnam_r(USER, PASSWD, BUFFER, BUFSIZE, PRESULT) fake_getpwnam_r(USER, PASSWD, BUFFER, BUFSIZE, PRESULT)
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+
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 #endif
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 #endif
token.c
History View file @ cb40315
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@@ -1,10 +1,61 @@
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+#include <stdlib.h>
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+#include <string.h>
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 #include <security/pam_modules.h>
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+#include <pwd.h>
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+#include <unistd.h>
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 #include "token.h"
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+#include "test_support.h"
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+
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+int user_is_known(const char *user) {
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+    struct passwd *passwd = (struct passwd *) malloc(sizeof(struct passwd));
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+    size_t bufsize = (size_t) sysconf(_SC_GETPW_R_SIZE_MAX);
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+    char * buffer = (char *) malloc(bufsize * sizeof(char));
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+    struct passwd *found_passwd = 0;
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+    getpwnam_r(user, passwd, buffer, bufsize, &found_passwd);
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+    int known = found_passwd != 0;
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+
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+    free(buffer);
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+    free(passwd);
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+
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+    return known;
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+
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+}
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+
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 int validate_token(const char *token) {
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-    return 1;
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+    int ok = 0;
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+
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+    char *user = 0;
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+
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+    // duplicate
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+    int token_length = strlen(token);
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+    user = (char *) malloc((token_length + 1) * sizeof(char));
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+    strcpy(user, token);
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+
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+    // find the first colon
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+    char *colon = strchr(user, ':');
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+    if (!colon) {
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+        goto finally;
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+    }
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+
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+    // poke a zero so dup is the username
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+    *colon = 0;
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+
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+    // check if user is known
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+    if(!user_is_known(user)) {
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+       goto finally;
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+    }
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+
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+    ok = 1;
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+
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+    // determine if user is system user
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+    // fail if not
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+    finally:
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+
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+    free(user);
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+    return ok;
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 }
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token_test.c
History View file @ cb40315
... ... 
@@ -1,12 +1,18 @@
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+#include <string.h>
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 #include "token.h"
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 #include "test_util.h"
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 const char *fake_user = "";
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 const char *fake_user_token = "";
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+struct passwd;
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 // all the fake system calls
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-
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+int fake_getpwnam_r(const char *nam, struct passwd *pwd, char *buffer, size_t bufsize, struct passwd **result) {
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+  int ok = !strcmp(nam, fake_user);
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+  *result = ok ? (struct passwd *)"" : 0;
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+  return !ok;
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+}
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 RESET_VARS_START
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 fake_user = "";
... ... 
@@ -30,9 +36,22 @@ int validate_compares_to_user_token() {
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 }
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+int validates_from_the_right_user() {
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+    //given
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+    fake_user = "jbalcita";
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+    fake_user_token = "123456";
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+
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+    //when
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+    int valid = validate_token("msmith:12346");
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+
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+    //then
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+    check(!valid, "expected result to be invalid");
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+    succeed();
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+}
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 int runtests() {
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     test(validate_compares_to_user_token);
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+    test(validates_from_the_right_user);
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     succeed();
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 }
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