From 465c2d93e2a2d20ac4844ad0d98b35f00e8063fb Mon Sep 17 00:00:00 2001 From: Su Laus Date: Tue, 8 Mar 2022 17:02:44 +0000 Subject: [PATCH] (CVE-2022-0891) tiffcrop: fix issue #380 and #382 heap buffer overflow in extractImageSection (cherry picked from commit 232282fd8f9c21eefe8d2d2b96cdbbb172fe7b7c) --- tools/tiffcrop.c | 84 ++++++++++++++++++------------------------------ 1 file changed, 32 insertions(+), 52 deletions(-) diff --git a/tools/tiffcrop.c b/tools/tiffcrop.c index a6129148..83cf80ad 100644 --- a/tools/tiffcrop.c +++ b/tools/tiffcrop.c @@ -6668,10 +6668,10 @@ extractImageSection(struct image_data *image, struct pageseg *section, #ifdef DEVELMODE uint32 img_length; #endif - uint32 j, shift1, shift2, trailing_bits; + uint32 j, shift1, trailing_bits; uint32 row, first_row, last_row, first_col, last_col; uint32 src_offset, dst_offset, row_offset, col_offset; - uint32 offset1, offset2, full_bytes; + uint32 offset1, full_bytes; uint32 sect_width; #ifdef DEVELMODE uint32 sect_length; @@ -6681,7 +6681,6 @@ extractImageSection(struct image_data *image, struct pageseg *section, #ifdef DEVELMODE int k; unsigned char bitset; - static char *bitarray = NULL; #endif img_width = image->width; @@ -6699,17 +6698,12 @@ extractImageSection(struct image_data *image, struct pageseg *section, dst_offset = 0; #ifdef DEVELMODE - if (bitarray == NULL) - { - if ((bitarray = (char *)malloc(img_width)) == NULL) - { - TIFFError ("", "DEBUG: Unable to allocate debugging bitarray"); - return (-1); - } - } + char bitarray[39]; #endif - /* rows, columns, width, length are expressed in pixels */ + /* rows, columns, width, length are expressed in pixels + * first_row, last_row, .. are index into image array starting at 0 to width-1, + * last_col shall be also extracted. */ first_row = section->y1; last_row = section->y2; first_col = section->x1; @@ -6719,9 +6713,14 @@ extractImageSection(struct image_data *image, struct pageseg *section, #ifdef DEVELMODE sect_length = last_row - first_row + 1; #endif - img_rowsize = ((img_width * bps + 7) / 8) * spp; + /* The read function loadImage() used copy separate plane data into a buffer as interleaved + * samples rather than separate planes so the same logic works to extract regions + * regardless of the way the data are organized in the input file. + * Furthermore, bytes and bits are arranged in buffer according to COMPRESSION=1 and FILLORDER=1 + */ + img_rowsize = (((img_width * spp * bps) + 7) / 8); /* row size in full bytes of source image */ full_bytes = (sect_width * spp * bps) / 8; /* number of COMPLETE bytes per row in section */ - trailing_bits = (sect_width * bps) % 8; + trailing_bits = (sect_width * spp * bps) % 8; /* trailing bits within the last byte of destination buffer */ #ifdef DEVELMODE TIFFError ("", "First row: %d, last row: %d, First col: %d, last col: %d\n", @@ -6734,10 +6733,9 @@ extractImageSection(struct image_data *image, struct pageseg *section, if ((bps % 8) == 0) { - col_offset = first_col * spp * bps / 8; + col_offset = (first_col * spp * bps) / 8; for (row = first_row; row <= last_row; row++) { - /* row_offset = row * img_width * spp * bps / 8; */ row_offset = row * img_rowsize; src_offset = row_offset + col_offset; @@ -6750,14 +6748,12 @@ extractImageSection(struct image_data *image, struct pageseg *section, } else { /* bps != 8 */ - shift1 = spp * ((first_col * bps) % 8); - shift2 = spp * ((last_col * bps) % 8); + shift1 = ((first_col * spp * bps) % 8); /* shift1 = bits to skip in the first byte of source buffer*/ for (row = first_row; row <= last_row; row++) { /* pull out the first byte */ row_offset = row * img_rowsize; - offset1 = row_offset + (first_col * bps / 8); - offset2 = row_offset + (last_col * bps / 8); + offset1 = row_offset + ((first_col * spp * bps) / 8); /* offset1 = offset into source of byte with first bits to be extracted */ #ifdef DEVELMODE for (j = 0, k = 7; j < 8; j++, k--) @@ -6769,12 +6765,12 @@ extractImageSection(struct image_data *image, struct pageseg *section, sprintf(&bitarray[9], " "); for (j = 10, k = 7; j < 18; j++, k--) { - bitset = *(src_buff + offset2) & (((unsigned char)1 << k)) ? 1 : 0; + bitset = *(src_buff + offset1 + full_bytes) & (((unsigned char)1 << k)) ? 1 : 0; sprintf(&bitarray[j], (bitset) ? "1" : "0"); } bitarray[18] = '\0'; - TIFFError ("", "Row: %3d Offset1: %d, Shift1: %d, Offset2: %d, Shift2: %d\n", - row, offset1, shift1, offset2, shift2); + TIFFError ("", "Row: %3d Offset1: %d, Shift1: %d, Offset2: %d, Trailing_bits: %d\n", + row, offset1, shift1, offset1+full_bytes, trailing_bits); #endif bytebuff1 = bytebuff2 = 0; @@ -6798,11 +6794,12 @@ extractImageSection(struct image_data *image, struct pageseg *section, if (trailing_bits != 0) { - bytebuff2 = src_buff[offset2] & ((unsigned char)255 << (7 - shift2)); + /* Only copy higher bits of samples and mask lower bits of not wanted column samples to zero */ + bytebuff2 = src_buff[offset1 + full_bytes] & ((unsigned char)255 << (8 - trailing_bits)); sect_buff[dst_offset] = bytebuff2; #ifdef DEVELMODE TIFFError ("", " Trailing bits src offset: %8d, Dst offset: %8d\n", - offset2, dst_offset); + offset1 + full_bytes, dst_offset); for (j = 30, k = 7; j < 38; j++, k--) { bitset = *(sect_buff + dst_offset) & (((unsigned char)1 << k)) ? 1 : 0; @@ -6821,8 +6818,10 @@ extractImageSection(struct image_data *image, struct pageseg *section, #endif for (j = 0; j <= full_bytes; j++) { + /* Skip the first shift1 bits and shift the source up by shift1 bits before save to destination.*/ + /* Attention: src_buff size needs to be some bytes larger than image size, because could read behind image here. */ bytebuff1 = src_buff[offset1 + j] & ((unsigned char)255 >> shift1); - bytebuff2 = src_buff[offset1 + j + 1] & ((unsigned char)255 << (7 - shift1)); + bytebuff2 = src_buff[offset1 + j + 1] & ((unsigned char)255 << (8 - shift1)); sect_buff[dst_offset + j] = (bytebuff1 << shift1) | (bytebuff2 >> (8 - shift1)); } #ifdef DEVELMODE @@ -6838,35 +6837,16 @@ extractImageSection(struct image_data *image, struct pageseg *section, #endif dst_offset += full_bytes; + /* Copy the trailing_bits for the last byte in the destination buffer. + Could come from one ore two bytes of the source buffer. */ if (trailing_bits != 0) { #ifdef DEVELMODE - TIFFError ("", " Trailing bits src offset: %8d, Dst offset: %8d\n", offset1 + full_bytes, dst_offset); -#endif - if (shift2 > shift1) - { - bytebuff1 = src_buff[offset1 + full_bytes] & ((unsigned char)255 << (7 - shift2)); - bytebuff2 = bytebuff1 & ((unsigned char)255 << shift1); - sect_buff[dst_offset] = bytebuff2; -#ifdef DEVELMODE - TIFFError ("", " Shift2 > Shift1\n"); + TIFFError("", " Trailing bits %4d src offset: %8d, Dst offset: %8d\n", trailing_bits, offset1 + full_bytes, dst_offset); #endif - } - else - { - if (shift2 < shift1) - { - bytebuff2 = ((unsigned char)255 << (shift1 - shift2 - 1)); - sect_buff[dst_offset] &= bytebuff2; -#ifdef DEVELMODE - TIFFError ("", " Shift2 < Shift1\n"); -#endif - } -#ifdef DEVELMODE - else - TIFFError ("", " Shift2 == Shift1\n"); -#endif - } + /* More than necessary bits are already copied into last destination buffer, + * only masking of last byte in destination buffer is necessary.*/ + sect_buff[dst_offset] &= ((uint8_t)0xFF << (8 - trailing_bits)); } #ifdef DEVELMODE sprintf(&bitarray[28], " "); @@ -7020,7 +7000,7 @@ writeImageSections(TIFF *in, TIFF *out, struct image_data *image, width = sections[i].x2 - sections[i].x1 + 1; length = sections[i].y2 - sections[i].y1 + 1; sectsize = (uint32) - ceil((width * image->bps + 7) / (double)8) * image->spp * length; + ceil((width * image->bps * image->spp + 7) / (double)8) * length; /* allocate a buffer if we don't have one already */ if (createImageSection(sectsize, sect_buff_ptr)) {