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/* Copyright (C) 2016-2023 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 Justin Viiret <justin.viiret@intel.com>
*
* Single pattern matcher that uses the Hyperscan regex matcher.
*/
#include "suricata-common.h"
#include "util-hyperscan.h"
#include "util-spm.h"
#include "util-spm-hs.h"
#include "util-debug.h"
#ifdef BUILD_HYPERSCAN
#include <hs.h>
/**
* \internal
* \brief Hyperscan match callback, called by hs_scan.
*/
static int MatchEvent(unsigned int id, unsigned long long from,
unsigned long long to, unsigned int flags, void *context)
{
uint64_t *match_offset = context;
BUG_ON(*match_offset != UINT64_MAX);
*match_offset = to;
return 1; /* Terminate matching. */
}
typedef struct SpmHsCtx_ {
hs_database_t *db;
uint16_t needle_len;
} SpmHsCtx;
static void HSDestroyCtx(SpmCtx *ctx)
{
if (ctx == NULL) {
return;
}
SpmHsCtx *sctx = ctx->ctx;
if (sctx) {
hs_free_database(sctx->db);
SCFree(sctx);
}
SCFree(ctx);
}
static int HSBuildDatabase(const uint8_t *needle, uint16_t needle_len,
int nocase, SpmHsCtx *sctx,
SpmGlobalThreadCtx *global_thread_ctx)
{
char *expr = HSRenderPattern(needle, needle_len);
if (expr == NULL) {
SCLogDebug("HSRenderPattern returned NULL");
return -1;
}
unsigned flags = nocase ? HS_FLAG_CASELESS : 0;
hs_database_t *db = NULL;
hs_compile_error_t *compile_err = NULL;
hs_error_t err = hs_compile(expr, flags, HS_MODE_BLOCK, NULL, &db,
&compile_err);
if (err != HS_SUCCESS) {
SCLogError("Unable to compile '%s' with Hyperscan, "
"returned %d.",
expr, err);
return -1;
}
SCFree(expr);
/* Update scratch for this database. */
hs_scratch_t *scratch = global_thread_ctx->ctx;
err = hs_alloc_scratch(db, &scratch);
if (err != HS_SUCCESS) {
/* If scratch allocation failed, this is not recoverable: other SPM
* contexts may need this scratch space. */
SCLogError("Unable to alloc scratch for Hyperscan, returned %d.", err);
return -1;
}
global_thread_ctx->ctx = scratch;
sctx->db = db;
sctx->needle_len = needle_len;
return 0;
}
static SpmCtx *HSInitCtx(const uint8_t *needle, uint16_t needle_len, int nocase,
SpmGlobalThreadCtx *global_thread_ctx)
{
SpmCtx *ctx = SCMalloc(sizeof(SpmCtx));
if (ctx == NULL) {
SCLogDebug("Unable to alloc SpmCtx.");
return NULL;
}
memset(ctx, 0, sizeof(SpmCtx));
ctx->matcher = SPM_HS;
SpmHsCtx *sctx = SCMalloc(sizeof(SpmHsCtx));
if (sctx == NULL) {
SCLogDebug("Unable to alloc SpmHsCtx.");
SCFree(ctx);
return NULL;
}
ctx->ctx = sctx;
memset(sctx, 0, sizeof(SpmHsCtx));
if (HSBuildDatabase(needle, needle_len, nocase, sctx,
global_thread_ctx) != 0) {
SCLogDebug("HSBuildDatabase failed.");
HSDestroyCtx(ctx);
return NULL;
}
return ctx;
}
static uint8_t *HSScan(const SpmCtx *ctx, SpmThreadCtx *thread_ctx,
const uint8_t *haystack, uint32_t haystack_len)
{
const SpmHsCtx *sctx = ctx->ctx;
hs_scratch_t *scratch = thread_ctx->ctx;
if (unlikely(haystack_len == 0)) {
return NULL;
}
uint64_t match_offset = UINT64_MAX;
hs_error_t err = hs_scan(sctx->db, (const char *)haystack, haystack_len, 0,
scratch, MatchEvent, &match_offset);
if (err != HS_SUCCESS && err != HS_SCAN_TERMINATED) {
/* An error value (other than HS_SCAN_TERMINATED) from hs_scan()
* indicates that it was passed an invalid database or scratch region,
* which is not something we can recover from at scan time. */
SCLogError("Hyperscan returned fatal error %d.", err);
exit(EXIT_FAILURE);
}
if (match_offset == UINT64_MAX) {
return NULL;
}
BUG_ON(match_offset < sctx->needle_len);
/* Note: existing API returns non-const ptr */
return (uint8_t *)haystack + (match_offset - sctx->needle_len);
}
static SpmGlobalThreadCtx *HSInitGlobalThreadCtx(void)
{
SpmGlobalThreadCtx *global_thread_ctx = SCMalloc(sizeof(SpmGlobalThreadCtx));
if (global_thread_ctx == NULL) {
SCLogDebug("Unable to alloc SpmGlobalThreadCtx.");
return NULL;
}
memset(global_thread_ctx, 0, sizeof(*global_thread_ctx));
global_thread_ctx->matcher = SPM_HS;
/* We store scratch in the HS-specific ctx. This will be initialized as
* patterns are compiled by SpmInitCtx. */
global_thread_ctx->ctx = NULL;
return global_thread_ctx;
}
static void HSDestroyGlobalThreadCtx(SpmGlobalThreadCtx *global_thread_ctx)
{
if (global_thread_ctx == NULL) {
return;
}
hs_free_scratch(global_thread_ctx->ctx);
SCFree(global_thread_ctx);
}
static void HSDestroyThreadCtx(SpmThreadCtx *thread_ctx)
{
if (thread_ctx == NULL) {
return;
}
hs_free_scratch(thread_ctx->ctx);
SCFree(thread_ctx);
}
static SpmThreadCtx *HSMakeThreadCtx(const SpmGlobalThreadCtx *global_thread_ctx)
{
SpmThreadCtx *thread_ctx = SCMalloc(sizeof(SpmThreadCtx));
if (thread_ctx == NULL) {
SCLogDebug("Unable to alloc SpmThreadCtx.");
return NULL;
}
memset(thread_ctx, 0, sizeof(*thread_ctx));
thread_ctx->matcher = SPM_HS;
if (global_thread_ctx->ctx != NULL) {
hs_scratch_t *scratch = NULL;
hs_error_t err = hs_clone_scratch(global_thread_ctx->ctx, &scratch);
if (err != HS_SUCCESS) {
SCLogError("Unable to clone scratch (error %d).", err);
exit(EXIT_FAILURE);
}
thread_ctx->ctx = scratch;
}
return thread_ctx;
}
void SpmHSRegister(void)
{
spm_table[SPM_HS].name = "hs";
spm_table[SPM_HS].InitGlobalThreadCtx = HSInitGlobalThreadCtx;
spm_table[SPM_HS].DestroyGlobalThreadCtx = HSDestroyGlobalThreadCtx;
spm_table[SPM_HS].MakeThreadCtx = HSMakeThreadCtx;
spm_table[SPM_HS].DestroyThreadCtx = HSDestroyThreadCtx;
spm_table[SPM_HS].InitCtx = HSInitCtx;
spm_table[SPM_HS].DestroyCtx = HSDestroyCtx;
spm_table[SPM_HS].Scan = HSScan;
}
#endif /* BUILD_HYPERSCAN */
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