This enables v8_enable_seeded_array_index_hash and add a test for it.
Fixes: https://hackerone.com/reports/3511792
deps: V8: backport 0a8b1cdcc8b2
Original commit message:
implement rapidhash secret generation
Bug: 409717082
Change-Id: I471f33d66de32002f744aeba534c1d34f71e27d2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/6733490
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: snek <snek@chromium.org>
Cr-Commit-Position: refs/heads/main@{#101499}
Refs: 0a8b1cdcc8
Co-authored-by: Joyee Cheung <joyeec9h3@gmail.com>
deps: V8: backport 185f0fe09b72
Original commit message:
[numbers] Refactor HashSeed as a lightweight view over ByteArray
Instead of copying the seed and secrets into a struct with value
fields, HashSeed now stores a pointer pointing either into the
read-only ByteArray, or the static default seed for off-heap
HashSeed::Default() calls. The underlying storage is always
8-byte aligned so we can cast it directly into a struct.
Change-Id: I5896a7f2ae24296eb4c80b757a5d90ac70a34866
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/7609720
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Joyee Cheung <joyee@igalia.com>
Cr-Commit-Position: refs/heads/main@{#105531}
Refs: 185f0fe09b
Co-authored-by: Joyee Cheung <joyeec9h3@gmail.com>
deps: V8: backport 1361b2a49d02
Original commit message:
[strings] improve array index hash distribution
Previously, the hashes stored in a Name's raw_hash_field for decimal
numeric strings (potential array indices) consist of the literal
integer value along with the length of the string. This means
consecutive numeric strings can have consecutive hash values, which
can lead to O(n^2) probing for insertion in the worst case when e.g.
a non-numeric string happen to land in the these buckets.
This patch adds a build-time flag v8_enable_seeded_array_index_hash that
scrambles the 24-bit array-index value stored in a Name's raw_hash_field
to improve the distribution.
x ^= x >> kShift; x = (x * m1) & kMask; // round 1
x ^= x >> kShift; x = (x * m2) & kMask; // round 2
x ^= x >> kShift; // finalize
To decode, apply the same steps with the modular inverses of m1 and m2
in reverse order.
x ^= x >> kShift; x = (x * m2_inv) & kMask; // round 1
x ^= x >> kShift; x = (x * m1_inv) & kMask; // round 2
x ^= x >> kShift; // finalize
where kShift = kArrayIndexValueBits / 2, kMask = kArrayIndexValueMask,
m1, m2 (both odd) are the lower bits of the rapidhash secrets, m1_inv,
m2_inv (modular inverses) are precomputed modular inverse of m1 and m2.
The pre-computed values are appended to the hash_seed ByteArray in
ReadOnlyRoots and accessed in generated code to reduce overhead.
In call sites that don't already have access to the seeds, we read them
from the current isolate group/isolate's read only roots.
To consolidate the code that encode/decode these hashes, this patch
adds MakeArrayIndexHash/DecodeArrayIndexFromHashField in C++ and CSA
that perform seeding/unseeding if enabled, and updates places where
encoding/decoding of array index is needed to use them.
Bug: 477515021
Change-Id: I350afe511951a54c4378396538152cc56565fd55
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/7564330
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Joyee Cheung <joyee@igalia.com>
Cr-Commit-Position: refs/heads/main@{#105596}
Refs: 1361b2a49d
Co-authored-by: Joyee Cheung <joyeec9h3@gmail.com>
deps: V8: cherry-pick aac14dd95e5b
Original commit message:
[string] add 3rd round to seeded array index hash
Since we already have 3 derived secrets, and arithmetics are
relatively cheap, add a 3rd round to the xorshift-multiply
seeding scheme. This brings the bias from ~3.4 to ~0.4.
Bug: 477515021
Change-Id: I1ef48954bcee8768d8c90db06ac8adb02f06cebf
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/7655117
Reviewed-by: Chengzhong Wu <cwu631@bloomberg.net>
Commit-Queue: Joyee Cheung <joyee@igalia.com>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#105824}
Refs: aac14dd95e
PR-URL: https://github.com/nodejs-private/node-private/pull/834
CVE-ID: CVE-2026-21717
af5c144ebc
