diff options
Diffstat (limited to 'vendor/golang.org/x/crypto/ssh/test/sshd_test_pw.c')
| -rw-r--r-- | vendor/golang.org/x/crypto/ssh/test/sshd_test_pw.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/ssh/test/sshd_test_pw.c b/vendor/golang.org/x/crypto/ssh/test/sshd_test_pw.c new file mode 100644 index 000000000..2794a563a --- /dev/null +++ b/vendor/golang.org/x/crypto/ssh/test/sshd_test_pw.c @@ -0,0 +1,173 @@ +// Copyright 2017 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// sshd_test_pw.c +// Wrapper to inject test password data for sshd PAM authentication +// +// This wrapper implements custom versions of getpwnam, getpwnam_r, +// getspnam and getspnam_r. These functions first call their real +// libc versions, then check if the requested user matches test user +// specified in env variable TEST_USER and if so replace the password +// with crypted() value of TEST_PASSWD env variable. +// +// Compile: +// gcc -Wall -shared -o sshd_test_pw.so -fPIC sshd_test_pw.c +// +// Compile with debug: +// gcc -DVERBOSE -Wall -shared -o sshd_test_pw.so -fPIC sshd_test_pw.c +// +// Run sshd: +// LD_PRELOAD="sshd_test_pw.so" TEST_USER="..." TEST_PASSWD="..." sshd ... + +// +build ignore + +#define _GNU_SOURCE +#include <string.h> +#include <pwd.h> +#include <shadow.h> +#include <dlfcn.h> +#include <stdlib.h> +#include <unistd.h> +#include <stdio.h> + +#ifdef VERBOSE +#define DEBUG(X...) fprintf(stderr, X) +#else +#define DEBUG(X...) while (0) { } +#endif + +/* crypt() password */ +static char * +pwhash(char *passwd) { + return strdup(crypt(passwd, "$6$")); +} + +/* Pointers to real functions in libc */ +static struct passwd * (*real_getpwnam)(const char *) = NULL; +static int (*real_getpwnam_r)(const char *, struct passwd *, char *, size_t, struct passwd **) = NULL; +static struct spwd * (*real_getspnam)(const char *) = NULL; +static int (*real_getspnam_r)(const char *, struct spwd *, char *, size_t, struct spwd **) = NULL; + +/* Cached test user and test password */ +static char *test_user = NULL; +static char *test_passwd_hash = NULL; + +static void +init(void) { + /* Fetch real libc function pointers */ + real_getpwnam = dlsym(RTLD_NEXT, "getpwnam"); + real_getpwnam_r = dlsym(RTLD_NEXT, "getpwnam_r"); + real_getspnam = dlsym(RTLD_NEXT, "getspnam"); + real_getspnam_r = dlsym(RTLD_NEXT, "getspnam_r"); + + /* abort if env variables are not defined */ + if (getenv("TEST_USER") == NULL || getenv("TEST_PASSWD") == NULL) { + fprintf(stderr, "env variables TEST_USER and TEST_PASSWD are missing\n"); + abort(); + } + + /* Fetch test user and test password from env */ + test_user = strdup(getenv("TEST_USER")); + test_passwd_hash = pwhash(getenv("TEST_PASSWD")); + + DEBUG("sshd_test_pw init():\n"); + DEBUG("\treal_getpwnam: %p\n", real_getpwnam); + DEBUG("\treal_getpwnam_r: %p\n", real_getpwnam_r); + DEBUG("\treal_getspnam: %p\n", real_getspnam); + DEBUG("\treal_getspnam_r: %p\n", real_getspnam_r); + DEBUG("\tTEST_USER: '%s'\n", test_user); + DEBUG("\tTEST_PASSWD: '%s'\n", getenv("TEST_PASSWD")); + DEBUG("\tTEST_PASSWD_HASH: '%s'\n", test_passwd_hash); +} + +static int +is_test_user(const char *name) { + if (test_user != NULL && strcmp(test_user, name) == 0) + return 1; + return 0; +} + +/* getpwnam */ + +struct passwd * +getpwnam(const char *name) { + struct passwd *pw; + + DEBUG("sshd_test_pw getpwnam(%s)\n", name); + + if (real_getpwnam == NULL) + init(); + if ((pw = real_getpwnam(name)) == NULL) + return NULL; + + if (is_test_user(name)) + pw->pw_passwd = strdup(test_passwd_hash); + + return pw; +} + +/* getpwnam_r */ + +int +getpwnam_r(const char *name, + struct passwd *pwd, + char *buf, + size_t buflen, + struct passwd **result) { + int r; + + DEBUG("sshd_test_pw getpwnam_r(%s)\n", name); + + if (real_getpwnam_r == NULL) + init(); + if ((r = real_getpwnam_r(name, pwd, buf, buflen, result)) != 0 || *result == NULL) + return r; + + if (is_test_user(name)) + pwd->pw_passwd = strdup(test_passwd_hash); + + return 0; +} + +/* getspnam */ + +struct spwd * +getspnam(const char *name) { + struct spwd *sp; + + DEBUG("sshd_test_pw getspnam(%s)\n", name); + + if (real_getspnam == NULL) + init(); + if ((sp = real_getspnam(name)) == NULL) + return NULL; + + if (is_test_user(name)) + sp->sp_pwdp = strdup(test_passwd_hash); + + return sp; +} + +/* getspnam_r */ + +int +getspnam_r(const char *name, + struct spwd *spbuf, + char *buf, + size_t buflen, + struct spwd **spbufp) { + int r; + + DEBUG("sshd_test_pw getspnam_r(%s)\n", name); + + if (real_getspnam_r == NULL) + init(); + if ((r = real_getspnam_r(name, spbuf, buf, buflen, spbufp)) != 0) + return r; + + if (is_test_user(name)) + spbuf->sp_pwdp = strdup(test_passwd_hash); + + return r; +} |