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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 | 1x 1x 1x 1x 1x 1x 1x 1x 42x 42x 42x 42x 84x 84x 84x 84x 84x 42x 42x 1x 1x 7x 7x 7x 7x 7x 5x 7x 10x 10x 10x 9x 10x 10x 7x 7x 1x 1x 20x 20x 20x 12x 8x 8x 20x 20x 4x 4x 4x 20x 20x 1x 1x 1x 20x 20x 20x 20x 2x 2x 2x 20x 20x 2x 2x 20x 13x 20x 1x 1x 13x 12x 1x 1x 13x 13x 13x 13x 6x 6x 6x 6x 6x 13x 7x 7x 7x 7x 7x 13x | import type { FileRangeReader } from "../file-range-reader.js";
import type { ElfHashSource, ElfHashTable } from "./hash-types.js";
import type { ElfBinaryLayout } from "./binary-layout-types.js";
import { validateElfHashTable } from "./hash-validation.js";
// Both hash headers use Elf32_Word even in ELF64. GNU Bloom words use the ELF address size.
// https://raw.githubusercontent.com/bminor/glibc/master/elf/dl-lookup.c
const readWords = async (
reader: FileRangeReader, offset: number, count: number, width: number, layout: ElfBinaryLayout
): Promise<bigint[]> => {
const words: bigint[] = [];
for (let index = 0; index < count; index += 1) {
const view = await reader.read(offset + index * width, width);
if (view.byteLength !== width) break;
words.push(width === 8 ? view.getBigUint64(0, layout.byteOrder === "little") :
BigInt(view.getUint32(0, layout.byteOrder === "little")));
}
return words;
};
const readGnuChains = async (
reader: FileRangeReader, source: ElfHashSource, table: Extract<ElfHashTable, { kind: "gnu" }>,
chainOffset: number, layout: ElfBinaryLayout
): Promise<void> => {
const maximumBucket = table.buckets.reduce((maximum, bucket) => Math.max(maximum, bucket), 0);
if (!maximumBucket) return;
const available = Math.floor((source.size - chainOffset) / 4);
for (let index = 0; index < available; index += 1) {
const view = await reader.read(source.offset + chainOffset + index * 4, 4);
if (view.byteLength < 4) break;
const value = view.getUint32(0, layout.byteOrder === "little");
table.chains.push(value);
if (index >= maximumBucket - table.symbolOffset && (value & 1)) return;
}
table.issues.push("GNU hash chain is unterminated or truncated.");
};
export const readElfHashTable = async (
reader: FileRangeReader, source: ElfHashSource, layout: ElfBinaryLayout
): Promise<ElfHashTable> => {
const table: ElfHashTable = source.kind === "sysv"
? { kind: "sysv", offset: source.offset, buckets: [], chains: [], issues: [] }
: { kind: "gnu", offset: source.offset, buckets: [], chains: [], issues: [],
symbolOffset: 0, bloomShift: 0, bloom: [] };
const headerSize = source.kind === "sysv" ? 8 : 16;
if (source.size < headerSize) {
table.issues.push("Hash table header is truncated or outside the file.");
return table;
}
const header = await readWords(reader, source.offset, headerSize / 4, 4, layout);
if (header.length !== headerSize / 4) {
table.issues.push("Hash table header is truncated.");
return table;
}
const bucketCount = Number(header[0]);
const extraCount = Number(header[table.kind === "gnu" ? 2 : 1]);
const extraWidth = table.kind === "gnu" ? layout.wordSize : 4;
if (headerSize + bucketCount * 4 + extraCount * extraWidth > source.size) {
table.issues.push("Hash table dimensions exceed the file range.");
return table;
}
await readHashArrays(reader, source, table, header, layout);
if (!completeArrays(table, bucketCount, extraCount)) {
table.issues.push("Hash table arrays are truncated.");
}
validateElfHashTable(table);
return table;
};
const completeArrays = (table: ElfHashTable, buckets: number, extra: number): boolean =>
table.buckets.length === buckets &&
(table.kind === "gnu" ? table.bloom.length : table.chains.length) === extra;
const readHashArrays = async (
reader: FileRangeReader, source: ElfHashSource, table: ElfHashTable,
header: bigint[], layout: ElfBinaryLayout
): Promise<void> => {
if (table.kind === "sysv") {
table.buckets = (await readWords(reader, source.offset + 8, Number(header[0]), 4, layout)).map(Number);
table.chains = (await readWords(reader, source.offset + 8 + Number(header[0]) * 4,
Number(header[1]), 4, layout)).map(Number);
return;
}
table.symbolOffset = Number(header[1]);
table.bloomShift = Number(header[3]);
table.bloom = await readWords(reader, source.offset + 16, Number(header[2]), layout.wordSize, layout);
const bucketOffset = 16 + Number(header[2]) * layout.wordSize;
table.buckets = (await readWords(reader, source.offset + bucketOffset, Number(header[0]), 4, layout)).map(Number);
await readGnuChains(reader, source, table, bucketOffset + Number(header[0]) * 4, layout);
};
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