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Diffstat (limited to 'src/app-layer-htp-xff.c')
| -rw-r--r-- | src/app-layer-htp-xff.c | 349 |
1 files changed, 349 insertions, 0 deletions
diff --git a/src/app-layer-htp-xff.c b/src/app-layer-htp-xff.c new file mode 100644 index 0000000..c145e58 --- /dev/null +++ b/src/app-layer-htp-xff.c @@ -0,0 +1,349 @@ +/* Copyright (C) 2014 Open Information Security Foundation + * + * You can copy, redistribute or modify this Program under the terms of + * the GNU General Public License version 2 as published by the Free + * Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * version 2 along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +/** + * \file + * + * \author Ignacio Sanchez <sanchezmartin.ji@gmail.com> + * \author Duarte Silva <duarte.silva@serializing.me> + */ + +#include "suricata-common.h" +#include "conf.h" + +#include "app-layer-parser.h" +#include "app-layer-htp.h" +#include "app-layer-htp-xff.h" + +#ifndef HAVE_MEMRCHR +#include "util-memrchr.h" +#endif + +#include "util-misc.h" +#include "util-unittest.h" + +/** XFF header value minimal length */ +#define XFF_CHAIN_MINLEN 7 +/** XFF header value maximum length */ +#define XFF_CHAIN_MAXLEN 256 +/** Default XFF header name */ +#define XFF_DEFAULT "X-Forwarded-For" + +/** \internal + * \brief parse XFF string + * \param input input string, might be modified + * \param output output buffer + * \param output_size size of output buffer + * \retval bool 1 ok, 0 fail + */ +static int ParseXFFString(char *input, char *output, int output_size) +{ + size_t len = strlen(input); + if (len == 0) + return 0; + + if (input[0] == '[') { + char *end = strchr(input, ']'); + if (end == NULL) // malformed, not closed + return 0; + + if (end != input+(len - 1)) { + SCLogDebug("data after closing bracket"); + // if we ever want to parse the port, we can do it here + } + + /* done, lets wrap up */ + input++; // skip past [ + *end = '\0'; // overwrite ], ignore anything after + + } else { + /* lets see if the xff string ends in a port */ + int c = 0; + int d = 0; + char *p = input; + while (*p != '\0') { + if (*p == ':') + c++; + if (*p == '.') + d++; + p++; + } + /* 3 dots: ipv4, one ':' port */ + if (d == 3 && c == 1) { + SCLogDebug("XFF w port %s", input); + char *x = strchr(input, ':'); + if (x) { + *x = '\0'; + SCLogDebug("XFF w/o port %s", input); + // if we ever want to parse the port, we can do it here + } + } + } + + SCLogDebug("XFF %s", input); + + /** Sanity check on extracted IP for IPv4 and IPv6 */ + uint32_t ip[4]; + if (inet_pton(AF_INET, input, ip) == 1 || + inet_pton(AF_INET6, input, ip) == 1) + { + strlcpy(output, input, output_size); + return 1; // OK + } + return 0; +} + +/** + * \brief Function to return XFF IP if any in the selected transaction. The + * caller needs to lock the flow. + * \retval 1 if the IP has been found and returned in dstbuf + * \retval 0 if the IP has not being found or error + */ +int HttpXFFGetIPFromTx(const Flow *f, uint64_t tx_id, HttpXFFCfg *xff_cfg, + char *dstbuf, int dstbuflen) +{ + uint8_t xff_chain[XFF_CHAIN_MAXLEN]; + HtpState *htp_state = NULL; + htp_tx_t *tx = NULL; + uint64_t total_txs = 0; + uint8_t *p_xff = NULL; + + htp_state = (HtpState *)FlowGetAppState(f); + + if (htp_state == NULL) { + SCLogDebug("no http state, XFF IP cannot be retrieved"); + return 0; + } + + total_txs = AppLayerParserGetTxCnt(f, htp_state); + if (tx_id >= total_txs) + return 0; + + tx = AppLayerParserGetTx(f->proto, ALPROTO_HTTP1, htp_state, tx_id); + if (tx == NULL) { + SCLogDebug("tx is NULL, XFF cannot be retrieved"); + return 0; + } + + htp_header_t *h_xff = NULL; + if (tx->request_headers != NULL) { + h_xff = htp_table_get_c(tx->request_headers, xff_cfg->header); + } + + if (h_xff != NULL && bstr_len(h_xff->value) >= XFF_CHAIN_MINLEN && + bstr_len(h_xff->value) < XFF_CHAIN_MAXLEN) { + + memcpy(xff_chain, bstr_ptr(h_xff->value), bstr_len(h_xff->value)); + xff_chain[bstr_len(h_xff->value)]=0; + + if (xff_cfg->flags & XFF_REVERSE) { + /** Get the last IP address from the chain */ + p_xff = memrchr(xff_chain, ' ', bstr_len(h_xff->value)); + if (p_xff == NULL) { + p_xff = xff_chain; + } else { + p_xff++; + } + } + else { + /** Get the first IP address from the chain */ + p_xff = memchr(xff_chain, ',', bstr_len(h_xff->value)); + if (p_xff != NULL) { + *p_xff = 0; + } + p_xff = xff_chain; + } + return ParseXFFString((char *)p_xff, dstbuf, dstbuflen); + } + return 0; +} + +/** + * \brief Function to return XFF IP if any. The caller needs to lock the flow. + * \retval 1 if the IP has been found and returned in dstbuf + * \retval 0 if the IP has not being found or error + */ +int HttpXFFGetIP(const Flow *f, HttpXFFCfg *xff_cfg, char *dstbuf, int dstbuflen) +{ + HtpState *htp_state = NULL; + uint64_t tx_id = 0; + uint64_t total_txs = 0; + + htp_state = (HtpState *)FlowGetAppState(f); + if (htp_state == NULL) { + SCLogDebug("no http state, XFF IP cannot be retrieved"); + goto end; + } + + total_txs = AppLayerParserGetTxCnt(f, htp_state); + for (; tx_id < total_txs; tx_id++) { + if (HttpXFFGetIPFromTx(f, tx_id, xff_cfg, dstbuf, dstbuflen) == 1) + return 1; + } + +end: + return 0; // Not found +} + +/** + * \brief Function to return XFF configuration from a configuration node. + */ +void HttpXFFGetCfg(ConfNode *conf, HttpXFFCfg *result) +{ + BUG_ON(result == NULL); + + ConfNode *xff_node = NULL; + + if (conf != NULL) + xff_node = ConfNodeLookupChild(conf, "xff"); + + if (xff_node != NULL && ConfNodeChildValueIsTrue(xff_node, "enabled")) { + const char *xff_mode = ConfNodeLookupChildValue(xff_node, "mode"); + + if (xff_mode != NULL && strcasecmp(xff_mode, "overwrite") == 0) { + result->flags |= XFF_OVERWRITE; + } else { + if (xff_mode == NULL) { + SCLogWarning("The XFF mode hasn't been defined, falling back to extra-data mode"); + } + else if (strcasecmp(xff_mode, "extra-data") != 0) { + SCLogWarning( + "The XFF mode %s is invalid, falling back to extra-data mode", xff_mode); + } + result->flags |= XFF_EXTRADATA; + } + + const char *xff_deployment = ConfNodeLookupChildValue(xff_node, "deployment"); + + if (xff_deployment != NULL && strcasecmp(xff_deployment, "forward") == 0) { + result->flags |= XFF_FORWARD; + } else { + if (xff_deployment == NULL) { + SCLogWarning("The XFF deployment hasn't been defined, falling back to reverse " + "proxy deployment"); + } + else if (strcasecmp(xff_deployment, "reverse") != 0) { + SCLogWarning("The XFF mode %s is invalid, falling back to reverse proxy deployment", + xff_deployment); + } + result->flags |= XFF_REVERSE; + } + + const char *xff_header = ConfNodeLookupChildValue(xff_node, "header"); + + if (xff_header != NULL) { + result->header = (char *) xff_header; + } else { + SCLogWarning("The XFF header hasn't been defined, using the default %s", XFF_DEFAULT); + result->header = XFF_DEFAULT; + } + } + else { + result->flags = XFF_DISABLED; + } +} + + +#ifdef UNITTESTS +static int XFFTest01(void) { + char input[] = "1.2.3.4:5678"; + char output[16]; + int r = ParseXFFString(input, output, sizeof(output)); + FAIL_IF_NOT(r == 1 && strcmp(output, "1.2.3.4") == 0); + PASS; +} + +static int XFFTest02(void) { + char input[] = "[12::34]:1234"; // thanks chort! + char output[16]; + int r = ParseXFFString(input, output, sizeof(output)); + FAIL_IF_NOT(r == 1 && strcmp(output, "12::34") == 0); + PASS; +} + +static int XFFTest03(void) { + char input[] = "[2a03:2880:1010:3f02:face:b00c:0:2]:80"; // thanks chort! + char output[46]; + int r = ParseXFFString(input, output, sizeof(output)); + FAIL_IF_NOT(r == 1 && strcmp(output, "2a03:2880:1010:3f02:face:b00c:0:2") == 0); + PASS; +} + +static int XFFTest04(void) { + char input[] = "[2a03:2880:1010:3f02:face:b00c:0:2]"; // thanks chort! + char output[46]; + int r = ParseXFFString(input, output, sizeof(output)); + FAIL_IF_NOT(r == 1 && strcmp(output, "2a03:2880:1010:3f02:face:b00c:0:2") == 0); + PASS; +} + +static int XFFTest05(void) { + char input[] = "[::ffff:1.2.3.4]:1234"; // thanks double-p + char output[46]; + int r = ParseXFFString(input, output, sizeof(output)); + FAIL_IF_NOT(r == 1 && strcmp(output, "::ffff:1.2.3.4") == 0); + PASS; +} + +static int XFFTest06(void) { + char input[] = "12::34"; + char output[46]; + int r = ParseXFFString(input, output, sizeof(output)); + FAIL_IF_NOT(r == 1 && strcmp(output, "12::34") == 0); + PASS; +} + +static int XFFTest07(void) { + char input[] = "1.2.3.4"; + char output[46]; + int r = ParseXFFString(input, output, sizeof(output)); + FAIL_IF_NOT(r == 1 && strcmp(output, "1.2.3.4") == 0); + PASS; +} + +static int XFFTest08(void) { + char input[] = "[1.2.3.4:1234"; + char output[46]; + int r = ParseXFFString(input, output, sizeof(output)); + FAIL_IF_NOT(r == 0); + PASS; +} + +static int XFFTest09(void) { + char input[] = "999.999.999.999:1234"; + char output[46]; + int r = ParseXFFString(input, output, sizeof(output)); + FAIL_IF_NOT(r == 0); + PASS; +} + +#endif + +void HTPXFFParserRegisterTests(void) +{ +#ifdef UNITTESTS + UtRegisterTest("XFFTest01", XFFTest01); + UtRegisterTest("XFFTest02", XFFTest02); + UtRegisterTest("XFFTest03", XFFTest03); + UtRegisterTest("XFFTest04", XFFTest04); + UtRegisterTest("XFFTest05", XFFTest05); + UtRegisterTest("XFFTest06", XFFTest06); + UtRegisterTest("XFFTest07", XFFTest07); + UtRegisterTest("XFFTest08", XFFTest08); + UtRegisterTest("XFFTest09", XFFTest09); +#endif +} |