clamav/libclamav/pe.h
Valerie Snyder aa7b7e9421
Swap clean cache from MD5 to SHA2-256
Change the clean-cache to use SHA2-256 instead of MD5.
Note that all references are changed to specify "SHA2-256" now instead
of "SHA256", for clarity. But there is no plan to add support for SHA3
algorithms at this time.

Significant code cleanup. E.g.:
- Implemented goto-done error handling.
- Used `uint8_t *` instead of `unsigned char *`.
- Use `bool` for boolean checks, rather than `int.
- Used `#defines` instead of magic numbers.
- Removed duplicate `#defines` for things like hash length.

Add new option to calculate and record additional hash types when the
"generate metadata JSON" feature is enabled:
- libclamav option: `CL_SCAN_GENERAL_STORE_EXTRA_HASHES`
- clamscan option: `--json-store-extra-hashes` (default off)
- clamd.conf option: `JsonStoreExtraHashes` (default 'no')

Renamed the sigtool option `--sha256` to `--sha2-256`.
The original option is still functional, but is deprecated.

For the "generate metadata JSON" feature, the file hash is now stored as
"sha2-256" instead of "FileMD5". If you enable the "extra hashes" option,
then it will also record "md5" and "sha1".

Deprecate and disable the internal "SHA collect" feature.
This option had been hidden behind C #ifdef checks for an option that
wasn't exposed through CMake, so it was basically unavailable anyways.

Changes to calculate file hashes when they're needed and no sooner.

For the FP feature in the matcher module, I have mimiced the
optimization in the FMAP scan routine which makes it so that it can
calculate multiple hashes in a single pass of the file.

The `HandlerType` feature stores a hash of the file in the scan ctx to
prevent retyping the exact same data more than once.
I removed that hash field and replaced it with an attribute flag that is
applied to the new recursion stack layer when retyping a file.
This also closes a minor bug that would prevent retyping a file with an
all-zero hash. :)

The work upgrading cache.c to support SHA2-256 sized hashes thanks to:
https://github.com/m-sola

CLAM-255
CLAM-1858
CLAM-1859
CLAM-1860
2025-08-14 21:23:30 -04:00

99 lines
4.2 KiB
C

/*
* Copyright (C) 2013-2025 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
* Copyright (C) 2007-2013 Sourcefire, Inc.
*
* Authors: Alberto Wu, Tomasz Kojm, Andrew Williams
*
* Acknowledgements: The header structures were based upon a PE format
* analysis by B. Luevelsmeyer.
*
* This program is free software; you can redistribute it and/or modify
* it 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
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
#ifndef __PE_H
#define __PE_H
#include "clamav.h"
#include "others.h"
#include "fmap.h"
#include "bcfeatures.h"
#include "pe_structs.h"
#include "execs.h"
/** Data for the bytecode PE hook
* \group_pe
*
* NOTE: This structure must stay in-sync with the ones defined within the
* clamav-bytecode-compiler source at:
* - clang/lib/Headers/bytecode_pe.h
* - llvm/tools/clang/lib/Headers/bytecode_pe.h
* We allocate space for this, populate the values via cli_peheader, and pass
* it to the bytecode sig runtime for use.
*
* TODO Next time we are making changes to the clamav-bytecode-compiler
* source, update pe_image_optional_hdr32 and pe_image_optional_hdr64 to
* remove DataDirectory from both (like with the definitions here). Then,
* remove opt32_dirs and opt64_dirs below. There's no need to have these
* bytes in 3 places! Also, consider using a union to hold opt32 and opt64,
* since you never need more than one at a time.
*/
struct cli_pe_hook_data {
uint32_t offset;
uint32_t ep; /**< EntryPoint as file offset */
uint16_t nsections; /**< Number of sections */
uint16_t dummy; /* align */
struct pe_image_file_hdr file_hdr; /**< Header for this PE file */
struct pe_image_optional_hdr32 opt32; /**< 32-bit PE optional header */
/** Our opt32 no longer includes DataDirectory[16], but the one in the
* bytecode compiler source still does. Add this here as a placeholder (and
* it gets used, so we need to populate it also */
struct pe_image_data_dir opt32_dirs[16];
uint32_t dummy2; /* align */
struct pe_image_optional_hdr64 opt64; /**< 64-bit PE optional header */
struct pe_image_data_dir opt64_dirs[16]; /** See note about opt32_dirs */
struct pe_image_data_dir dirs[16]; /**< PE data directory header */
uint32_t e_lfanew; /**< address of new exe header */
uint32_t overlays; /**< number of overlays */
int32_t overlays_sz; /**< size of overlays */
uint32_t hdr_size; /**< internally needed by rawaddr */
};
int cli_scanpe(cli_ctx *ctx);
enum {
CL_GENHASH_PE_CLASS_SECTION,
CL_GENHASH_PE_CLASS_IMPTBL,
/* place new class types above this line */
CL_GENHASH_PE_CLASS_LAST
};
// For info about these, see the cli_peheader definition in pe.c
#define CLI_PEHEADER_OPT_NONE 0x0
#define CLI_PEHEADER_OPT_COLLECT_JSON 0x1
#define CLI_PEHEADER_OPT_DBG_PRINT_INFO 0x2
#define CLI_PEHEADER_OPT_EXTRACT_VINFO 0x4
#define CLI_PEHEADER_OPT_STRICT_ON_PE_ERRORS 0x8
#define CLI_PEHEADER_OPT_REMOVE_MISSING_SECTIONS 0x10
cl_error_t cli_pe_targetinfo(cli_ctx *ctx, struct cli_exe_info *peinfo);
cl_error_t cli_peheader(fmap_t *map, struct cli_exe_info *peinfo, uint32_t opts, cli_ctx *ctx);
cl_error_t cli_check_auth_header(cli_ctx *ctx, struct cli_exe_info *peinfo);
cl_error_t cli_genhash_pe(cli_ctx *ctx, unsigned int class, cli_hash_type_t type, stats_section_t *hashes);
uint32_t cli_rawaddr(uint32_t, const struct cli_exe_section *, uint16_t, unsigned int *, size_t, uint32_t);
void findres(uint32_t, uint32_t, fmap_t *map, struct cli_exe_info *, int (*)(void *, uint32_t, uint32_t, uint32_t, uint32_t), void *);
#endif