diff options
Diffstat (limited to 'lib/security.c')
| -rw-r--r-- | lib/security.c | 604 |
1 files changed, 604 insertions, 0 deletions
diff --git a/lib/security.c b/lib/security.c new file mode 100644 index 000000000..b70310b89 --- /dev/null +++ b/lib/security.c @@ -0,0 +1,604 @@ +/* This source code was modified by Martin Hedenfalk <mhe@stacken.kth.se> for + * use in Curl. His latest changes were done 2000-09-18. + * + * It has since been patched and modified a lot by Daniel Stenberg + * <daniel@haxx.se> to make it better applied to curl conditions, and to make + * it not use globals, pollute name space and more. This source code awaits a + * rewrite to work around the paragraph 2 in the BSD licenses as explained + * below. + * + * Copyright (c) 1998, 1999 Kungliga Tekniska Högskolan + * (Royal Institute of Technology, Stockholm, Sweden). + * + * Copyright (C) 2001 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al. + * + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * 3. Neither the name of the Institute nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. */ + +#include "setup.h" + +#ifndef CURL_DISABLE_FTP +#if defined(HAVE_KRB4) || defined(HAVE_GSSAPI) + +#ifdef HAVE_NETDB_H +#include <netdb.h> +#endif + +#ifdef HAVE_LIMITS_H +#include <limits.h> +#endif + +#include "urldata.h" +#include "curl_base64.h" +#include "curl_memory.h" +#include "krb4.h" +#include "ftp.h" +#include "sendf.h" +#include "rawstr.h" +#include "warnless.h" + +/* The last #include file should be: */ +#include "memdebug.h" + +static const struct { + enum protection_level level; + const char *name; +} level_names[] = { + { PROT_CLEAR, "clear" }, + { PROT_SAFE, "safe" }, + { PROT_CONFIDENTIAL, "confidential" }, + { PROT_PRIVATE, "private" } +}; + +static enum protection_level +name_to_level(const char *name) +{ + int i; + for(i = 0; i < (int)sizeof(level_names)/(int)sizeof(level_names[0]); i++) + if(checkprefix(name, level_names[i].name)) + return level_names[i].level; + return PROT_NONE; +} + +/* Convert a protocol |level| to its char representation. + We take an int to catch programming mistakes. */ +static char level_to_char(int level) { + switch(level) { + case PROT_CLEAR: + return 'C'; + case PROT_SAFE: + return 'S'; + case PROT_CONFIDENTIAL: + return 'E'; + case PROT_PRIVATE: + return 'P'; + case PROT_CMD: + /* Fall through */ + default: + /* Those 2 cases should not be reached! */ + break; + } + DEBUGASSERT(0); + /* Default to the most secure alternative. */ + return 'P'; +} + +static const struct Curl_sec_client_mech * const mechs[] = { +#if defined(HAVE_GSSAPI) + &Curl_krb5_client_mech, +#endif +#if defined(HAVE_KRB4) + &Curl_krb4_client_mech, +#endif + NULL +}; + +/* Send an FTP command defined by |message| and the optional arguments. The + function returns the ftp_code. If an error occurs, -1 is returned. */ +static int ftp_send_command(struct connectdata *conn, const char *message, ...) +{ + int ftp_code; + ssize_t nread; + va_list args; + char print_buffer[50]; + + va_start(args, message); + vsnprintf(print_buffer, sizeof(print_buffer), message, args); + va_end(args); + + if(Curl_ftpsendf(conn, print_buffer) != CURLE_OK) { + ftp_code = -1; + } + else { + if(Curl_GetFTPResponse(&nread, conn, &ftp_code) != CURLE_OK) + ftp_code = -1; + } + + (void)nread; /* Unused */ + return ftp_code; +} + +/* Read |len| from the socket |fd| and store it in |to|. Return a CURLcode + saying whether an error occurred or CURLE_OK if |len| was read. */ +static CURLcode +socket_read(curl_socket_t fd, void *to, size_t len) +{ + char *to_p = to; + CURLcode code; + ssize_t nread; + + while(len > 0) { + code = Curl_read_plain(fd, to_p, len, &nread); + if(code == CURLE_OK) { + len -= nread; + to_p += nread; + } + else { + /* FIXME: We are doing a busy wait */ + if(code == CURLE_AGAIN) + continue; + return code; + } + } + return CURLE_OK; +} + + +/* Write |len| bytes from the buffer |to| to the socket |fd|. Return a + CURLcode saying whether an error occurred or CURLE_OK if |len| was + written. */ +static CURLcode +socket_write(struct connectdata *conn, curl_socket_t fd, const void *to, + size_t len) +{ + const char *to_p = to; + CURLcode code; + ssize_t written; + + while(len > 0) { + code = Curl_write_plain(conn, fd, to_p, len, &written); + if(code == CURLE_OK) { + len -= written; + to_p += written; + } + else { + /* FIXME: We are doing a busy wait */ + if(code == CURLE_AGAIN) + continue; + return code; + } + } + return CURLE_OK; +} + +static CURLcode read_data(struct connectdata *conn, + curl_socket_t fd, + struct krb4buffer *buf) +{ + int len; + void* tmp; + CURLcode ret; + + ret = socket_read(fd, &len, sizeof(len)); + if(ret != CURLE_OK) + return ret; + + len = ntohl(len); + tmp = realloc(buf->data, len); + if(tmp == NULL) + return CURLE_OUT_OF_MEMORY; + + buf->data = tmp; + ret = socket_read(fd, buf->data, len); + if(ret != CURLE_OK) + return ret; + buf->size = conn->mech->decode(conn->app_data, buf->data, len, + conn->data_prot, conn); + buf->index = 0; + return CURLE_OK; +} + +static size_t +buffer_read(struct krb4buffer *buf, void *data, size_t len) +{ + if(buf->size - buf->index < len) + len = buf->size - buf->index; + memcpy(data, (char*)buf->data + buf->index, len); + buf->index += len; + return len; +} + +/* Matches Curl_recv signature */ +static ssize_t sec_recv(struct connectdata *conn, int sockindex, + char *buffer, size_t len, CURLcode *err) +{ + size_t bytes_read; + size_t total_read = 0; + curl_socket_t fd = conn->sock[sockindex]; + + *err = CURLE_OK; + + /* Handle clear text response. */ + if(conn->sec_complete == 0 || conn->data_prot == PROT_CLEAR) + return read(fd, buffer, len); + + if(conn->in_buffer.eof_flag) { + conn->in_buffer.eof_flag = 0; + return 0; + } + + bytes_read = buffer_read(&conn->in_buffer, buffer, len); + len -= bytes_read; + total_read += bytes_read; + buffer += bytes_read; + + while(len > 0) { + if(read_data(conn, fd, &conn->in_buffer) != CURLE_OK) + return -1; + if(conn->in_buffer.size == 0) { + if(bytes_read > 0) + conn->in_buffer.eof_flag = 1; + return bytes_read; + } + bytes_read = buffer_read(&conn->in_buffer, buffer, len); + len -= bytes_read; + total_read += bytes_read; + buffer += bytes_read; + } + /* FIXME: Check for overflow */ + return total_read; +} + +/* Send |length| bytes from |from| to the |fd| socket taking care of encoding + and negociating with the server. |from| can be NULL. */ +/* FIXME: We don't check for errors nor report any! */ +static void do_sec_send(struct connectdata *conn, curl_socket_t fd, + const char *from, int length) +{ + int bytes, htonl_bytes; /* 32-bit integers for htonl */ + char *buffer = NULL; + char *cmd_buffer; + size_t cmd_size = 0; + CURLcode error; + enum protection_level prot_level = conn->data_prot; + bool iscmd = (prot_level == PROT_CMD)?TRUE:FALSE; + + DEBUGASSERT(prot_level > PROT_NONE && prot_level < PROT_LAST); + + if(iscmd) { + if(!strncmp(from, "PASS ", 5) || !strncmp(from, "ACCT ", 5)) + prot_level = PROT_PRIVATE; + else + prot_level = conn->command_prot; + } + bytes = conn->mech->encode(conn->app_data, from, length, prot_level, + (void**)&buffer, conn); + if(!buffer || bytes <= 0) + return; /* error */ + + if(iscmd) { + error = Curl_base64_encode(conn->data, buffer, curlx_sitouz(bytes), + &cmd_buffer, &cmd_size); + if(error) { + free(buffer); + return; /* error */ + } + if(cmd_size > 0) { + static const char *enc = "ENC "; + static const char *mic = "MIC "; + if(prot_level == PROT_PRIVATE) + socket_write(conn, fd, enc, 4); + else + socket_write(conn, fd, mic, 4); + + socket_write(conn, fd, cmd_buffer, cmd_size); + socket_write(conn, fd, "\r\n", 2); + infof(conn->data, "Send: %s%s\n", prot_level == PROT_PRIVATE?enc:mic, + cmd_buffer); + free(cmd_buffer); + } + } + else { + htonl_bytes = htonl(bytes); + socket_write(conn, fd, &htonl_bytes, sizeof(htonl_bytes)); + socket_write(conn, fd, buffer, curlx_sitouz(bytes)); + } + free(buffer); +} + +static ssize_t sec_write(struct connectdata *conn, curl_socket_t fd, + const char *buffer, size_t length) +{ + /* FIXME: Check for overflow */ + ssize_t tx = 0, len = conn->buffer_size; + + len -= conn->mech->overhead(conn->app_data, conn->data_prot, + curlx_sztosi(len)); + if(len <= 0) + len = length; + while(length) { + if(len >= 0 || length < (size_t)len) { + /* FIXME: Check for overflow. */ + len = length; + } + do_sec_send(conn, fd, buffer, curlx_sztosi(len)); + length -= len; + buffer += len; + tx += len; + } + return tx; +} + +/* Matches Curl_send signature */ +static ssize_t sec_send(struct connectdata *conn, int sockindex, + const void *buffer, size_t len, CURLcode *err) +{ + curl_socket_t fd = conn->sock[sockindex]; + *err = CURLE_OK; + return sec_write(conn, fd, buffer, len); +} + +int Curl_sec_read_msg(struct connectdata *conn, char *buffer, + enum protection_level level) +{ + /* decoded_len should be size_t or ssize_t but conn->mech->decode returns an + int */ + int decoded_len; + char *buf; + int ret_code; + size_t decoded_sz = 0; + CURLcode error; + + DEBUGASSERT(level > PROT_NONE && level < PROT_LAST); + + error = Curl_base64_decode(buffer + 4, (unsigned char **)&buf, &decoded_sz); + if(error || decoded_sz == 0) + return -1; + + if(decoded_sz > (size_t)INT_MAX) { + free(buf); + return -1; + } + decoded_len = curlx_uztosi(decoded_sz); + + decoded_len = conn->mech->decode(conn->app_data, buf, decoded_len, + level, conn); + if(decoded_len <= 0) { + free(buf); + return -1; + } + + if(conn->data->set.verbose) { + buf[decoded_len] = '\n'; + Curl_debug(conn->data, CURLINFO_HEADER_IN, buf, decoded_len + 1, conn); + } + + buf[decoded_len] = '\0'; + DEBUGASSERT(decoded_len > 3); + if(buf[3] == '-') + ret_code = 0; + else { + /* Check for error? */ + sscanf(buf, "%d", &ret_code); + } + + if(buf[decoded_len - 1] == '\n') + buf[decoded_len - 1] = '\0'; + /* FIXME: Is |buffer| length always greater than |decoded_len|? */ + strcpy(buffer, buf); + free(buf); + return ret_code; +} + +/* FIXME: The error code returned here is never checked. */ +static int sec_set_protection_level(struct connectdata *conn) +{ + int code; + char* pbsz; + static unsigned int buffer_size = 1 << 20; /* 1048576 */ + enum protection_level level = conn->request_data_prot; + + DEBUGASSERT(level > PROT_NONE && level < PROT_LAST); + + if(!conn->sec_complete) { + infof(conn->data, "Trying to change the protection level after the" + "completion of the data exchange.\n"); + return -1; + } + + /* Bail out if we try to set up the same level */ + if(conn->data_prot == level) + return 0; + + if(level) { + code = ftp_send_command(conn, "PBSZ %u", buffer_size); + if(code < 0) + return -1; + + if(code/100 != 2) { + failf(conn->data, "Failed to set the protection's buffer size."); + return -1; + } + conn->buffer_size = buffer_size; + + pbsz = strstr(conn->data->state.buffer, "PBSZ="); + if(pbsz) { + /* FIXME: Checks for errors in sscanf? */ + sscanf(pbsz, "PBSZ=%u", &buffer_size); + if(buffer_size < conn->buffer_size) + conn->buffer_size = buffer_size; + } + } + + /* Now try to negiociate the protection level. */ + code = ftp_send_command(conn, "PROT %c", level_to_char(level)); + + if(code < 0) + return -1; + + if(code/100 != 2) { + failf(conn->data, "Failed to set the protection level."); + return -1; + } + + conn->data_prot = level; + if(level == PROT_PRIVATE) + conn->command_prot = level; + + return 0; +} + +int +Curl_sec_request_prot(struct connectdata *conn, const char *level) +{ + enum protection_level l = name_to_level(level); + if(l == PROT_NONE) + return -1; + DEBUGASSERT(l > PROT_NONE && l < PROT_LAST); + conn->request_data_prot = l; + return 0; +} + +static CURLcode choose_mech(struct connectdata *conn) +{ + int ret; + struct SessionHandle *data = conn->data; + const struct Curl_sec_client_mech * const *mech; + void *tmp_allocation; + const char *mech_name; + + for(mech = mechs; (*mech); ++mech) { + mech_name = (*mech)->name; + /* We have no mechanism with a NULL name but keep this check */ + DEBUGASSERT(mech_name != NULL); + if(mech_name == NULL) { + infof(data, "Skipping mechanism with empty name (%p)\n", mech); + continue; + } + tmp_allocation = realloc(conn->app_data, (*mech)->size); + if(tmp_allocation == NULL) { + failf(data, "Failed realloc of size %u", (*mech)->size); + mech = NULL; + return CURLE_OUT_OF_MEMORY; + } + conn->app_data = tmp_allocation; + + if((*mech)->init) { + ret = (*mech)->init(conn->app_data); + if(ret != 0) { + infof(data, "Failed initialization for %s. Skipping it.\n", mech_name); + continue; + } + } + + infof(data, "Trying mechanism %s...\n", mech_name); + ret = ftp_send_command(conn, "AUTH %s", mech_name); + if(ret < 0) + /* FIXME: This error is too generic but it is OK for now. */ + return CURLE_COULDNT_CONNECT; + + if(ret/100 != 3) { + switch(ret) { + case 504: + infof(data, "Mechanism %s is not supported by the server (server " + "returned ftp code: 504).\n", mech_name); + break; + case 534: + infof(data, "Mechanism %s was rejected by the server (server returned " + "ftp code: 534).\n", mech_name); + break; + default: + if(ret/100 == 5) { + infof(data, "server does not support the security extensions\n"); + return CURLE_USE_SSL_FAILED; + } + break; + } + continue; + } + + /* Authenticate */ + ret = (*mech)->auth(conn->app_data, conn); + + if(ret == AUTH_CONTINUE) + continue; + else if(ret != AUTH_OK) { + /* Mechanism has dumped the error to stderr, don't error here. */ + return -1; + } + DEBUGASSERT(ret == AUTH_OK); + + conn->mech = *mech; + conn->sec_complete = 1; + conn->recv[FIRSTSOCKET] = sec_recv; + conn->send[FIRSTSOCKET] = sec_send; + conn->recv[SECONDARYSOCKET] = sec_recv; + conn->send[SECONDARYSOCKET] = sec_send; + conn->command_prot = PROT_SAFE; + /* Set the requested protection level */ + /* BLOCKING */ + (void)sec_set_protection_level(conn); + break; + } + + return mech != NULL ? CURLE_OK : CURLE_FAILED_INIT; +} + +CURLcode +Curl_sec_login(struct connectdata *conn) +{ + return choose_mech(conn); +} + + +void +Curl_sec_end(struct connectdata *conn) +{ + if(conn->mech != NULL && conn->mech->end) + conn->mech->end(conn->app_data); + if(conn->app_data) { + free(conn->app_data); + conn->app_data = NULL; + } + if(conn->in_buffer.data) { + free(conn->in_buffer.data); + conn->in_buffer.data = NULL; + conn->in_buffer.size = 0; + conn->in_buffer.index = 0; + /* FIXME: Is this really needed? */ + conn->in_buffer.eof_flag = 0; + } + conn->sec_complete = 0; + conn->data_prot = PROT_CLEAR; + conn->mech = NULL; +} + +#endif /* HAVE_KRB4 || HAVE_GSSAPI */ + +#endif /* CURL_DISABLE_FTP */ |