From 51cc94bf2ac85cf70f77b5a9ee08fff672091530 Mon Sep 17 00:00:00 2001 From: n1073645 Date: Fri, 8 Nov 2019 13:38:17 +0000 Subject: [PATCH 1/3] Made GIF extractor more robust --- src/core/lib/FileSignatures.mjs | 39 ++++++++++++++++++--------------- 1 file changed, 21 insertions(+), 18 deletions(-) diff --git a/src/core/lib/FileSignatures.mjs b/src/core/lib/FileSignatures.mjs index 8c0a3aff..7942ebb3 100644 --- a/src/core/lib/FileSignatures.mjs +++ b/src/core/lib/FileSignatures.mjs @@ -2455,10 +2455,11 @@ export function extractGIF(bytes, offset) { //Move to Graphic Control Extension for frame #1. stream.continueUntil([0x21, 0xf9]); + stream.moveForwardsBy(2); while (stream.hasMore()) { //Move to Image descriptor. - stream.continueUntil(0x2c); + stream.moveForwardsBy(stream.getBytes(1)[0]+1); //Move past Image descriptor to the image data. stream.moveForwardsBy(11); @@ -2474,7 +2475,7 @@ export function extractGIF(bytes, offset) { //When the end of the file is [0x00, 0x3b], end. if (stream.getBytes(1)[0] === 0x3b) break; - stream.moveBackwardsBy(1); + stream.moveForwardsBy(1); } return stream.carve(); } @@ -2818,37 +2819,39 @@ export function extractGZIP(bytes, offset) { /** + * BZIP2 extractor. + * * @param {Uint8Array} bytes * @param {Number} offset * @returns {Uint8Array} */ -export function extractBZIP2(bytes, offset){ +export function extractBZIP2(bytes, offset) { const stream = new Stream(bytes.slice(offset)); - + //The EOFs shifted between all possible combinations. - var lookingfor = [ - [0x77, 0x24, 0x53, 0x85, 0x09], - [0xee, 0x48, 0xa7, 0x0a, 0x12], - [0xdc, 0x91, 0x4e, 0x14, 0x24], - [0xb9, 0x22, 0x9c, 0x28, 0x48], - [0x72, 0x45, 0x38, 0x50, 0x90], - [0xbb, 0x92, 0x29, 0xc2, 0x84], - [0x5d, 0xc9, 0x14, 0xe1, 0x42], - [0x2e, 0xe4, 0x8a, 0x70, 0xa1], - [0x17, 0x72, 0x45, 0x38, 0x50]]; - - for(let i = 0; i < 9; i++){ + const lookingfor = [ + [0x77, 0x24, 0x53, 0x85, 0x09], + [0xee, 0x48, 0xa7, 0x0a, 0x12], + [0xdc, 0x91, 0x4e, 0x14, 0x24], + [0xb9, 0x22, 0x9c, 0x28, 0x48], + [0x72, 0x45, 0x38, 0x50, 0x90], + [0xbb, 0x92, 0x29, 0xc2, 0x84], + [0x5d, 0xc9, 0x14, 0xe1, 0x42], + [0x2e, 0xe4, 0x8a, 0x70, 0xa1], + [0x17, 0x72, 0x45, 0x38, 0x50]]; + + for (let i = 0; i < lookingfor.length; i++) { //Continue until an EOF. stream.continueUntil(lookingfor[i]); - if(stream.getBytes(5).join("") == lookingfor[i].join("")) + if (stream.getBytes(5).join("") === lookingfor[i].join("")) break; //Jump back to the start if invalid EOF. stream.moveTo(0); } stream.moveForwardsBy(4); - + console.log("test: ", stream.position.toString(16)); return stream.carve(); } From f3864b00feacb77fc0987e58c9c64f7efded9a5d Mon Sep 17 00:00:00 2001 From: n1073645 Date: Fri, 8 Nov 2019 13:40:09 +0000 Subject: [PATCH 2/3] Made GIF extractor more robust --- src/core/lib/FileSignatures.mjs | 1 - 1 file changed, 1 deletion(-) diff --git a/src/core/lib/FileSignatures.mjs b/src/core/lib/FileSignatures.mjs index 7942ebb3..d4f0ee22 100644 --- a/src/core/lib/FileSignatures.mjs +++ b/src/core/lib/FileSignatures.mjs @@ -2851,7 +2851,6 @@ export function extractBZIP2(bytes, offset) { stream.moveTo(0); } stream.moveForwardsBy(4); - console.log("test: ", stream.position.toString(16)); return stream.carve(); } From 04f1fa06adec69550fed0e01b6f94625288968e0 Mon Sep 17 00:00:00 2001 From: n1474335 Date: Fri, 8 Nov 2019 13:49:39 +0000 Subject: [PATCH 3/3] Tidied up GIF and BZIP2 extractors --- src/core/lib/FileSignatures.mjs | 34 +++++++++++++++++---------------- 1 file changed, 18 insertions(+), 16 deletions(-) diff --git a/src/core/lib/FileSignatures.mjs b/src/core/lib/FileSignatures.mjs index d4f0ee22..d8b819bb 100644 --- a/src/core/lib/FileSignatures.mjs +++ b/src/core/lib/FileSignatures.mjs @@ -2450,31 +2450,33 @@ export function extractJPEG(bytes, offset) { export function extractGIF(bytes, offset) { const stream = new Stream(bytes.slice(offset)); - //Move to application extension block. + // Move to application extension block. stream.continueUntil([0x21, 0xff]); - //Move to Graphic Control Extension for frame #1. + // Move to Graphic Control Extension for frame #1. stream.continueUntil([0x21, 0xf9]); stream.moveForwardsBy(2); + while (stream.hasMore()) { + // Move to Image descriptor. + stream.moveForwardsBy(stream.readInt(1) + 1); - //Move to Image descriptor. - stream.moveForwardsBy(stream.getBytes(1)[0]+1); - - //Move past Image descriptor to the image data. + // Move past Image descriptor to the image data. stream.moveForwardsBy(11); - //Loop until next Graphic Control Extension. + // Loop until next Graphic Control Extension. while (stream.getBytes(2) !== [0x21, 0xf9]) { stream.moveBackwardsBy(2); - stream.moveForwardsBy(stream.getBytes(1)[0]); - if (!stream.getBytes(1)[0]) + stream.moveForwardsBy(stream.readInt(1)); + if (!stream.readInt(1)) break; stream.moveBackwardsBy(1); } - //When the end of the file is [0x00, 0x3b], end. - if (stream.getBytes(1)[0] === 0x3b) + + // When the end of the file is [0x00, 0x3b], end. + if (stream.readInt(1) === 0x3b) break; + stream.moveForwardsBy(1); } return stream.carve(); @@ -2828,7 +2830,7 @@ export function extractGZIP(bytes, offset) { export function extractBZIP2(bytes, offset) { const stream = new Stream(bytes.slice(offset)); - //The EOFs shifted between all possible combinations. + // The EOFs shifted between all possible combinations. const lookingfor = [ [0x77, 0x24, 0x53, 0x85, 0x09], [0xee, 0x48, 0xa7, 0x0a, 0x12], @@ -2838,16 +2840,16 @@ export function extractBZIP2(bytes, offset) { [0xbb, 0x92, 0x29, 0xc2, 0x84], [0x5d, 0xc9, 0x14, 0xe1, 0x42], [0x2e, 0xe4, 0x8a, 0x70, 0xa1], - [0x17, 0x72, 0x45, 0x38, 0x50]]; + [0x17, 0x72, 0x45, 0x38, 0x50] + ]; for (let i = 0; i < lookingfor.length; i++) { - - //Continue until an EOF. + // Continue until an EOF. stream.continueUntil(lookingfor[i]); if (stream.getBytes(5).join("") === lookingfor[i].join("")) break; - //Jump back to the start if invalid EOF. + // Jump back to the start if invalid EOF. stream.moveTo(0); } stream.moveForwardsBy(4);