Move fuzzing code to fuzz/ subdirectory, improve Makefile.in

fuzz/fuzz-common.c

@@ -0,0 +1,311 @@
+#include "includes.h"
+
+#include "includes.h"
+#include "fuzz.h"
+#include "dbutil.h"
+#include "runopts.h"
+#include "crypto_desc.h"
+#include "session.h"
+#include "dbrandom.h"
+#include "bignum.h"
+#include "atomicio.h"
+#include "fuzz-wrapfd.h"
+
+struct dropbear_fuzz_options fuzz;
+
+static void fuzz_dropbear_log(int UNUSED(priority), const char* format, va_list param);
+static void load_fixed_hostkeys(void);
+static void load_fixed_client_key(void);
+
+void fuzz_common_setup(void) {
+	disallow_core();
+    fuzz.fuzzing = 1;
+    fuzz.wrapfds = 1;
+    fuzz.do_jmp = 1;
+    fuzz.input = m_malloc(sizeof(buffer));
+    _dropbear_log = fuzz_dropbear_log;
+    crypto_init();
+    fuzz_seed();
+    /* let any messages get flushed */
+    setlinebuf(stdout);
+}
+
+int fuzz_set_input(const uint8_t *Data, size_t Size) {
+
+    fuzz.input->data = (unsigned char*)Data;
+    fuzz.input->size = Size;
+    fuzz.input->len = Size;
+    fuzz.input->pos = 0;
+
+    memset(&ses, 0x0, sizeof(ses));
+    memset(&svr_ses, 0x0, sizeof(svr_ses));
+    memset(&cli_ses, 0x0, sizeof(cli_ses));
+    wrapfd_setup(fuzz.input);
+
+    fuzz_seed();
+
+    return DROPBEAR_SUCCESS;
+}
+
+#if DEBUG_TRACE
+static void fuzz_dropbear_log(int UNUSED(priority), const char* format, va_list param) {
+    if (debug_trace) {
+        char printbuf[1024];
+        vsnprintf(printbuf, sizeof(printbuf), format, param);
+        fprintf(stderr, "%s\n", printbuf);
+    }
+}
+#else
+static void fuzz_dropbear_log(int UNUSED(priority), const char* UNUSED(format), va_list UNUSED(param)) {
+    /* No print */
+}
+#endif /* DEBUG_TRACE */
+
+void fuzz_svr_setup(void) {
+    fuzz_common_setup();
+    
+    _dropbear_exit = svr_dropbear_exit;
+
+    char *argv[] = { 
+		"dropbear",
+        "-E", 
+    };
+
+    int argc = sizeof(argv) / sizeof(*argv);
+    svr_getopts(argc, argv);
+
+    load_fixed_hostkeys();
+}
+
+void fuzz_cli_setup(void) {
+    fuzz_common_setup();
+    
+	_dropbear_exit = cli_dropbear_exit;
+	_dropbear_log = cli_dropbear_log;
+
+    char *argv[] = { 
+		"dbclient",
+		"-y",
+        "localhost",
+        "uptime"
+    };
+
+    int argc = sizeof(argv) / sizeof(*argv);
+    cli_getopts(argc, argv);
+
+    load_fixed_client_key();
+    /* Avoid password prompt */
+    setenv(DROPBEAR_PASSWORD_ENV, "password", 1);
+}
+
+#include "fuzz-hostkeys.c"   
+
+static void load_fixed_client_key(void) {
+
+    buffer *b = buf_new(3000);
+    sign_key *key;
+    enum signkey_type keytype;
+
+    key = new_sign_key();
+    keytype = DROPBEAR_SIGNKEY_ANY;
+    buf_putbytes(b, keyed25519, keyed25519_len);
+    buf_setpos(b, 0);
+    if (buf_get_priv_key(b, key, &keytype) == DROPBEAR_FAILURE) {
+        dropbear_exit("failed fixed ed25519 hostkey");
+    }
+    list_append(cli_opts.privkeys, key);
+
+    buf_free(b);
+}
+
+static void load_fixed_hostkeys(void) {
+
+    buffer *b = buf_new(3000);
+    enum signkey_type type;
+
+    TRACE(("load fixed hostkeys"))
+
+    svr_opts.hostkey = new_sign_key();
+
+    buf_setlen(b, 0);
+    buf_putbytes(b, keyr, keyr_len);
+    buf_setpos(b, 0);
+    type = DROPBEAR_SIGNKEY_RSA;
+    if (buf_get_priv_key(b, svr_opts.hostkey, &type) == DROPBEAR_FAILURE) {
+        dropbear_exit("failed fixed rsa hostkey");
+    }
+
+    buf_setlen(b, 0);
+    buf_putbytes(b, keyd, keyd_len);
+    buf_setpos(b, 0);
+    type = DROPBEAR_SIGNKEY_DSS;
+    if (buf_get_priv_key(b, svr_opts.hostkey, &type) == DROPBEAR_FAILURE) {
+        dropbear_exit("failed fixed dss hostkey");
+    }
+
+    buf_setlen(b, 0);
+    buf_putbytes(b, keye, keye_len);
+    buf_setpos(b, 0);
+    type = DROPBEAR_SIGNKEY_ECDSA_NISTP256;
+    if (buf_get_priv_key(b, svr_opts.hostkey, &type) == DROPBEAR_FAILURE) {
+        dropbear_exit("failed fixed ecdsa hostkey");
+    }
+
+    buf_setlen(b, 0);
+    buf_putbytes(b, keyed25519, keyed25519_len);
+    buf_setpos(b, 0);
+    type = DROPBEAR_SIGNKEY_ED25519;
+    if (buf_get_priv_key(b, svr_opts.hostkey, &type) == DROPBEAR_FAILURE) {
+        dropbear_exit("failed fixed ed25519 hostkey");
+    }
+
+    buf_free(b);
+}
+
+void fuzz_kex_fakealgos(void) {
+    ses.newkeys->recv.crypt_mode = &dropbear_mode_none;
+}
+
+void fuzz_get_socket_address(int UNUSED(fd), char **local_host, char **local_port,
+                        char **remote_host, char **remote_port, int UNUSED(host_lookup)) {
+    if (local_host) {
+        *local_host = m_strdup("fuzzlocalhost");
+    }
+    if (local_port) {
+        *local_port = m_strdup("1234");
+    }
+    if (remote_host) {
+        *remote_host = m_strdup("fuzzremotehost");
+    }
+    if (remote_port) {
+        *remote_port = m_strdup("9876");
+    }
+}
+
+/* cut down version of svr_send_msg_kexdh_reply() that skips slow maths. Still populates structures */
+void fuzz_fake_send_kexdh_reply(void) {
+    assert(!ses.dh_K);
+    m_mp_alloc_init_multi(&ses.dh_K, NULL);
+    mp_set_ul(ses.dh_K, 12345678uL);
+    finish_kexhashbuf();
+}
+
+/* fake version of spawn_command() */
+int fuzz_spawn_command(int *ret_writefd, int *ret_readfd, int *ret_errfd, pid_t *ret_pid) {
+    *ret_writefd = wrapfd_new();
+    *ret_readfd = wrapfd_new();
+    if (ret_errfd) {
+        *ret_errfd = wrapfd_new();
+    }
+    *ret_pid = 999;
+    return DROPBEAR_SUCCESS;
+}
+
+int fuzz_run_preauth(const uint8_t *Data, size_t Size, int skip_kexmaths) {
+    static int once = 0;
+    if (!once) {
+        fuzz_svr_setup();
+        fuzz.skip_kexmaths = skip_kexmaths;
+        once = 1;
+    }
+
+    if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) {
+        return 0;
+    }
+
+    /*
+      get prefix, allowing for future extensibility. input format is
+      string prefix
+          uint32 wrapfd seed
+          ... to be extended later
+      [bytes] ssh input stream
+    */
+
+    /* be careful to avoid triggering buffer.c assertions */
+    if (fuzz.input->len < 8) {
+        return 0;
+    }
+    size_t prefix_size = buf_getint(fuzz.input);
+    if (prefix_size != 4) {
+        return 0;
+    }
+    uint32_t wrapseed = buf_getint(fuzz.input);
+    wrapfd_setseed(wrapseed);
+
+    int fakesock = wrapfd_new();
+
+    m_malloc_set_epoch(1);
+    if (setjmp(fuzz.jmp) == 0) {
+        svr_session(fakesock, fakesock);
+        m_malloc_free_epoch(1, 0);
+    } else {
+        m_malloc_free_epoch(1, 1);
+        TRACE(("dropbear_exit longjmped"))
+        /* dropbear_exit jumped here */
+    }
+
+    return 0;
+}
+
+int fuzz_run_client(const uint8_t *Data, size_t Size, int skip_kexmaths) {
+    static int once = 0;
+    if (!once) {
+        fuzz_cli_setup();
+        fuzz.skip_kexmaths = skip_kexmaths;
+        once = 1;
+    }
+
+    if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) {
+        return 0;
+    }
+
+    /*
+      get prefix, allowing for future extensibility. input format is
+      string prefix
+          uint32 wrapfd seed
+          ... to be extended later
+      [bytes] ssh input stream
+    */
+
+    /* be careful to avoid triggering buffer.c assertions */
+    if (fuzz.input->len < 8) {
+        return 0;
+    }
+    size_t prefix_size = buf_getint(fuzz.input);
+    if (prefix_size != 4) {
+        return 0;
+    }
+    uint32_t wrapseed = buf_getint(fuzz.input);
+    wrapfd_setseed(wrapseed);
+
+    int fakesock = wrapfd_new();
+
+    m_malloc_set_epoch(1);
+    if (setjmp(fuzz.jmp) == 0) {
+        cli_session(fakesock, fakesock, NULL, 0);
+        m_malloc_free_epoch(1, 0);
+    } else {
+        m_malloc_free_epoch(1, 1);
+        TRACE(("dropbear_exit longjmped"))
+        /* dropbear_exit jumped here */
+    }
+
+    return 0;
+}
+
+const void* fuzz_get_algo(const algo_type *algos, const char* name) {
+    const algo_type *t;
+    for (t = algos; t->name; t++) {
+        if (strcmp(t->name, name) == 0) {
+            return t->data;
+        }
+    }
+    assert(0);
+}
+
+void fuzz_dump(const unsigned char* data, size_t len) {
+    TRACE(("dump %zu", len))
+    if (fuzz.dumping) {
+        assert(atomicio(vwrite, fuzz.recv_dumpfd, (void*)data, len) == len);
+    }
+}