/* File: file_lnk.c Copyright (C) 2008 Christophe GRENIER This software is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. 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 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_lnk) #ifdef HAVE_CONFIG_H #include #endif #ifdef HAVE_STRING_H #include #endif #include #include "types.h" #include "filegen.h" #include "common.h" #ifdef DEBUG_LNK #include "log.h" #endif /*@ requires valid_register_header_check(file_stat); */ static void register_header_check_lnk(file_stat_t *file_stat); const file_hint_t file_hint_lnk= { .extension="lnk", .description="MS Windows Link", .max_filesize=PHOTOREC_MAX_FILE_SIZE, .recover=1, .enable_by_default=1, .register_header_check=®ister_header_check_lnk }; static const unsigned char lnk_reserved[10]= {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}; struct lnk_header_s { uint32_t magic; /* 0h Always 0000004Ch ‘L’ */ char guid[16]; /* 4h GUID of shortcut files */ uint32_t flags; /* 14h */ uint32_t file_attributes; /* 18h */ uint64_t ctime; /* 1Ch */ uint64_t atime; /* 24h */ uint64_t mtime; /* 2Ch */ uint32_t file_length; /* 34h */ uint32_t icon_number; /* 38h */ uint32_t showWnd_value; /* 3Ch */ uint32_t hot_key; /* 40h */ uint64_t always_zero; /* 44h */ } __attribute__ ((gcc_struct, __packed__)); /* These constants comes from winedump/lnk.c */ #define SLDF_HAS_ID_LIST 1 #define SLDF_HAS_LINK_INFO 2 #define SLDF_HAS_NAME 4 #define SLDF_HAS_RELPATH 8 #define SLDF_HAS_WORKINGDIR 0x10 #define SLDF_HAS_ARGS 0x20 #define SLDF_HAS_ICONLOCATION 0x40 #define SLDF_UNICODE 0x80 #define SLDF_HAS_LOGO3ID 0x800 #define SLDF_HAS_DARWINID 0x1000 /*@ @ requires buffer_size > 0x4c; @ requires \valid_read(buffer + (0 .. buffer_size-1)); @ terminates \true; @ assigns \nothing; @*/ static unsigned int lnk_get_size(const unsigned char *buffer, const unsigned int buffer_size) { const struct lnk_header_s* lnk_head=(const struct lnk_header_s*)buffer; const uint32_t flags=le32(lnk_head->flags); unsigned int i=0x4c; /* .LNK File Header */ /* avoid out of bound read access */ if(i >= buffer_size - 4) return 0; if((flags&SLDF_HAS_ID_LIST)!=0) { /* The Shell Item Id List */ const uint16_t *ptr=(const uint16_t *)&buffer[i]; const unsigned int len=le16(*ptr); #ifdef DEBUG_LNK log_debug("LNK Shell Item Id List at 0x%04x=%04x\n", i, len); #endif i+=2; i+=len; } /* avoid out of bound read access */ if(i >= buffer_size - 4) return 0; if((flags&SLDF_HAS_LINK_INFO)!=0) { /* File location info */ const uint32_t *ptr=(const uint32_t *)&buffer[i]; const unsigned int len=le32(*ptr); #ifdef DEBUG_LNK log_debug("LNK File location info at 0x%04x %u bytes\n", i, len); #endif /* Discard too big files, avoid overflow */ if(len >= 0x10000000) return 0; i+=len; } /* avoid out of bound read access */ if(i >= buffer_size - 2) return 0; if((flags&SLDF_HAS_NAME)!=0) { /* Description string */ const uint16_t *ptr=(const uint16_t *)&buffer[i]; unsigned int len=le16(*ptr); if((flags& SLDF_UNICODE)!=0) len*=2; i+=2; #ifdef DEBUG_LNK log_debug("LNK description string at 0x%04x %u bytes\n", i, len); #endif i+=len; } /* avoid out of bound read access */ if(i >= buffer_size - 2) return 0; if((flags&SLDF_HAS_RELPATH)!=0) { /* Relative path */ const uint16_t *ptr=(const uint16_t *)&buffer[i]; unsigned int len=le16(*ptr); if((flags& SLDF_UNICODE)!=0) len*=2; i+=2; #ifdef DEBUG_LNK log_debug("LNK relative path at 0x%04x=%04x\n", i, len); #endif i+=len; } /* avoid out of bound read access */ if(i >= buffer_size - 2) return 0; if((flags&SLDF_HAS_WORKINGDIR)!=0) { /* Working directory */ const uint16_t *ptr=(const uint16_t *)&buffer[i]; unsigned int len=le16(*ptr); if((flags& SLDF_UNICODE)!=0) len*=2; i+=2; #ifdef DEBUG_LNK log_debug("LNK Working directory at 0x%04x %u bytes\n", i, len); #endif i+=len; } /* avoid out of bound read access */ if(i >= buffer_size - 2) return 0; if((flags&SLDF_HAS_ARGS)!=0) { /* Command line string */ const uint16_t *ptr=(const uint16_t *)&buffer[i]; unsigned int len=le16(*ptr); if((flags& SLDF_UNICODE)!=0) len*=2; i+=2; #ifdef DEBUG_LNK log_debug("LNK Command line string at 0x%04x %u bytes\n", i, len); #endif i+=len; } /* avoid out of bound read access */ if(i >= buffer_size - 2) return 0; if((flags&SLDF_HAS_ICONLOCATION)!=0) { /* Icon filename string */ const uint16_t *ptr=(const uint16_t *)&buffer[i]; unsigned int len=le16(*ptr); if((flags& SLDF_UNICODE)!=0) len*=2; i+=2; #ifdef DEBUG_LNK log_debug("LNK Icon filename string at 0x%04x=%04x\n", i, len); #endif i+=len; } /* avoid out of bound read access */ if(i >= buffer_size - 2) return 0; /*@ @ loop invariant i < buffer_size-2; @ loop assigns i; @ loop variant buffer_size-2 - i; @*/ while(1) { /* avoid out of bound read access */ const uint16_t *ptr; unsigned int len; ptr=(const uint16_t *)&buffer[i]; /*@ assert \valid_read(ptr); */ len=le16(*ptr); #ifdef DEBUG_LNK log_debug("LNK 0x%04x - %u bytes\n", i, len); #endif if(len == 0) { #ifdef DEBUG_LNK log_debug("LNK size %u (0x%04x)\n", i, i); #endif return i; } i+=2; if(i >= buffer_size - 2) return 0; } } /*@ @ requires buffer_size >= 0x4c; @ requires separation: \separated(&file_hint_lnk, buffer+(..), file_recovery, file_recovery_new); @ requires valid_header_check_param(buffer, buffer_size, safe_header_only, file_recovery, file_recovery_new); @ ensures valid_header_check_result(\result, file_recovery_new); @ assigns *file_recovery_new; @*/ static int header_check_lnk(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new) { unsigned int len; if(memcmp(&buffer[0x42], lnk_reserved, sizeof(lnk_reserved))!=0) return 0; len=lnk_get_size(buffer, buffer_size); if(len < 0x4c || len > 1048576) return 0; reset_file_recovery(file_recovery_new); file_recovery_new->extension=file_hint_lnk.extension; file_recovery_new->calculated_file_size=len; file_recovery_new->data_check=&data_check_size; file_recovery_new->file_check=&file_check_size; // file_recovery_new->time=td_ntfs2utc(le64(lnk_head->ctime)); return 1; } static void register_header_check_lnk(file_stat_t *file_stat) { static const unsigned char lnk_header[20]= { 'L', 0x00, 0x00, 0x00, /* magic */ 0x01, 0x14, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x46 /* GUID */ }; register_header_check(0, lnk_header,sizeof(lnk_header), &header_check_lnk, file_stat); } #endif