denyhosts/clamav/libclamav/cpio.c

/*
 *  Copyright (C) 2013-2022 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
 *  Copyright (C) 2009-2013 Sourcefire, Inc.
 *
 *  Authors: Tomasz Kojm <tkojm@clamav.net>
 *
 *  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.
 */

#if HAVE_CONFIG_H
#include "clamav-config.h"
#endif

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include "clamav.h"
#include "others.h"
#include "cpio.h"
#include "scanners.h"
#include "matcher.h"

struct cpio_hdr_old {
    uint16_t magic;
    uint16_t dev;
    uint16_t ino;
    uint16_t mode;
    uint16_t uid;
    uint16_t gid;
    uint16_t nlink;
    uint16_t rdev;
    uint16_t mtime[2];
    uint16_t namesize;
    uint16_t filesize[2];
};

struct cpio_hdr_odc {
    char magic[6];
    char dev[6];
    char ino[6];
    char mode[6];
    char uid[6];
    char gid[6];
    char nlink[6];
    char rdev[6];
    char mtime[11];
    char namesize[6];
    char filesize[11];
};

struct cpio_hdr_newc {
    char magic[6];
    char ino[8];
    char mode[8];
    char uid[8];
    char gid[8];
    char nlink[8];
    char mtime[8];
    char filesize[8];
    char devmajor[8];
    char devminor[8];
    char rdevmajor[8];
    char rdevminor[8];
    char namesize[8];
    char check[8];
};

#define EC16(v, conv) (conv ? cbswap16(v) : v)

static void sanitname(char *name)
{
    while (*name) {
        if (!isascii(*name) || strchr("%\\\t\n\r", *name))
            *name = '_';
        name++;
    }
}

cl_error_t cli_scancpio_old(cli_ctx *ctx)
{
    cl_error_t status = CL_SUCCESS;
    struct cpio_hdr_old hdr_old;
    char *fmap_name = NULL;
    char name[513];
    unsigned int file = 0, trailer = 0;
    uint32_t filesize, namesize, hdr_namesize;
    int conv;
    size_t pos = 0;

    memset(name, 0, sizeof(name));

    while (fmap_readn(ctx->fmap, &hdr_old, pos, sizeof(hdr_old)) == sizeof(hdr_old)) {
        pos += sizeof(hdr_old);
        if (!hdr_old.magic && trailer) {
            status = CL_SUCCESS;
            goto done;
        }

        if (hdr_old.magic == 070707) {
            conv = 0;
        } else if (hdr_old.magic == 0143561) {
            conv = 1;
        } else {
            cli_dbgmsg("cli_scancpio_old: Invalid magic number\n");
            status = CL_EFORMAT;
            goto done;
        }

        cli_dbgmsg("CPIO: -- File %u --\n", ++file);

        if (hdr_old.namesize) {
            hdr_namesize = EC16(hdr_old.namesize, conv);
            namesize     = MIN(sizeof(name), hdr_namesize);
            if (fmap_readn(ctx->fmap, &name, pos, namesize) != namesize) {
                cli_dbgmsg("cli_scancpio_old: Can't read file name\n");
                status = CL_EFORMAT;
                goto done;
            }
            pos += namesize;
            name[namesize - 1] = 0;
            sanitname(name);
            cli_dbgmsg("CPIO: Name: %s\n", name);
            if (!strcmp(name, "TRAILER!!!")) {
                trailer = 1;
            }

            if (namesize < hdr_namesize) {
                if (hdr_namesize % 2) {
                    hdr_namesize++;
                }
                pos += hdr_namesize - namesize;
            } else if (hdr_namesize % 2) {
                pos++;
            }

            fmap_name = name;
        }
        filesize = (uint32_t)((uint32_t)EC16(hdr_old.filesize[0], conv) << 16 | EC16(hdr_old.filesize[1], conv));
        cli_dbgmsg("CPIO: Filesize: %u\n", filesize);
        if (!filesize)
            continue;

        status = cli_matchmeta(ctx, name, filesize, filesize, 0, file, 0, NULL);
        if (status != CL_SUCCESS) {
            goto done;
        }

        if ((EC16(hdr_old.mode, conv) & 0170000) != 0100000) {
            cli_dbgmsg("CPIO: Not a regular file, skipping\n");
        } else {
            status = cli_magic_scan_nested_fmap_type(ctx->fmap, pos, filesize, ctx, CL_TYPE_ANY, fmap_name, LAYER_ATTRIBUTES_NONE);
            if (status != CL_SUCCESS) {
                goto done;
            }
        }
        if (filesize % 2) {
            filesize++;
        }

        pos += filesize;
    }

done:

    return status;
}

cl_error_t cli_scancpio_odc(cli_ctx *ctx)
{
    cl_error_t status = CL_SUCCESS;
    struct cpio_hdr_odc hdr_odc;
    char name[513] = {0}, buff[12] = {0};
    unsigned int file = 0, trailer = 0;
    uint32_t filesize = 0, namesize = 0, hdr_namesize = 0;
    size_t pos = 0;

    memset(&hdr_odc, 0, sizeof(hdr_odc));

    while (fmap_readn(ctx->fmap, &hdr_odc, pos, sizeof(hdr_odc)) == sizeof(hdr_odc)) {
        pos += sizeof(hdr_odc);
        if (!hdr_odc.magic[0] && trailer) {
            status = CL_SUCCESS;
            goto done;
        }

        if (strncmp(hdr_odc.magic, "070707", 6)) {
            cli_dbgmsg("cli_scancpio_odc: Invalid magic string\n");
            status = CL_EFORMAT;
            goto done;
        }

        cli_dbgmsg("CPIO: -- File %u --\n", ++file);

        strncpy(buff, hdr_odc.namesize, 6);
        buff[6] = 0;
        if (sscanf(buff, "%o", &hdr_namesize) != 1) {
            cli_dbgmsg("cli_scancpio_odc: Can't convert name size\n");
            status = CL_EFORMAT;
            goto done;
        }
        if (hdr_namesize) {
            namesize = MIN(sizeof(name), hdr_namesize);
            if (fmap_readn(ctx->fmap, &name, pos, namesize) != namesize) {
                cli_dbgmsg("cli_scancpio_odc: Can't read file name\n");
                status = CL_EFORMAT;
                goto done;
            }
            pos += namesize;
            name[namesize - 1] = 0;
            sanitname(name);
            cli_dbgmsg("CPIO: Name: %s\n", name);
            if (!strcmp(name, "TRAILER!!!")) {
                trailer = 1;
            }

            if (namesize < hdr_namesize) {
                pos += hdr_namesize - namesize;
            }
        }

        strncpy(buff, hdr_odc.filesize, 11);
        buff[11] = 0;
        if (sscanf(buff, "%o", &filesize) != 1) {
            cli_dbgmsg("cli_scancpio_odc: Can't convert file size\n");
            status = CL_EFORMAT;
            goto done;
        }
        cli_dbgmsg("CPIO: Filesize: %u\n", filesize);
        if (!filesize) {
            continue;
        }

        status = cli_matchmeta(ctx, name, filesize, filesize, 0, file, 0, NULL);
        if (status == CL_VIRUS) {
            goto done;
        }

        status = cli_magic_scan_nested_fmap_type(ctx->fmap, pos, filesize, ctx, CL_TYPE_ANY, name, LAYER_ATTRIBUTES_NONE);
        if (status != CL_SUCCESS) {
            goto done;
        }

        pos += filesize;
    }

done:

    return status;
}

cl_error_t cli_scancpio_newc(cli_ctx *ctx, int crc)
{
    cl_error_t status = CL_SUCCESS;
    struct cpio_hdr_newc hdr_newc;
    char name[513], buff[9];
    unsigned int file = 0, trailer = 0;
    uint32_t filesize, namesize, hdr_namesize, pad;
    size_t pos = 0;

    memset(name, 0, 513);

    while (fmap_readn(ctx->fmap, &hdr_newc, pos, sizeof(hdr_newc)) == sizeof(hdr_newc)) {
        pos += sizeof(hdr_newc);
        if (!hdr_newc.magic[0] && trailer) {
            status = CL_SUCCESS;
            goto done;
        }

        if ((!crc && strncmp(hdr_newc.magic, "070701", 6)) || (crc && strncmp(hdr_newc.magic, "070702", 6))) {
            cli_dbgmsg("cli_scancpio_newc: Invalid magic string\n");
            status = CL_EFORMAT;
            goto done;
        }

        cli_dbgmsg("CPIO: -- File %u --\n", ++file);

        strncpy(buff, hdr_newc.namesize, 8);
        buff[8] = 0;
        if (sscanf(buff, "%x", &hdr_namesize) != 1) {
            cli_dbgmsg("cli_scancpio_newc: Can't convert name size\n");
            status = CL_EFORMAT;
            goto done;
        }
        if (hdr_namesize) {
            namesize = MIN(sizeof(name), hdr_namesize);
            if (fmap_readn(ctx->fmap, &name, pos, namesize) != namesize) {
                cli_dbgmsg("cli_scancpio_newc: Can't read file name\n");
                status = CL_EFORMAT;
                goto done;
            }
            pos += namesize;
            name[namesize - 1] = 0;
            sanitname(name);
            cli_dbgmsg("CPIO: Name: %s\n", name);
            if (!strcmp(name, "TRAILER!!!")) {
                trailer = 1;
            }

            pad = (4 - (sizeof(hdr_newc) + hdr_namesize) % 4) % 4;
            if (namesize < hdr_namesize) {
                if (pad) {
                    hdr_namesize += pad;
                }
                pos += hdr_namesize - namesize;
            } else if (pad) {
                pos += pad;
            }
        }

        strncpy(buff, hdr_newc.filesize, 8);
        buff[8] = 0;
        if (sscanf(buff, "%x", &filesize) != 1) {
            cli_dbgmsg("cli_scancpio_newc: Can't convert file size\n");
            status = CL_EFORMAT;
            goto done;
        }
        cli_dbgmsg("CPIO: Filesize: %u\n", filesize);
        if (!filesize) {
            continue;
        }

        status = cli_matchmeta(ctx, name, filesize, filesize, 0, file, 0, NULL);
        if (status == CL_VIRUS) {
            goto done;
        }

        status = cli_magic_scan_nested_fmap_type(ctx->fmap, pos, filesize, ctx, CL_TYPE_ANY, name, LAYER_ATTRIBUTES_NONE);
        if (status != CL_SUCCESS) {
            goto done;
        }

        if ((pad = filesize % 4)) {
            filesize += (4 - pad);
        }

        pos += filesize;
    }

done:

    return status;
}