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fix: alignment for pairing bufs #61

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Merged
spiral-ladder merged 1 commit into from
Mar 4, 2026
Merged

fix: alignment for pairing bufs #61

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12 changes: 7 additions & 5 deletions src/Pairing.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,10 @@ ctx: *c.blst_pairing,

const Self = @This();

/// Required alignment for the pairing buffer. The opaque C struct contains
/// `uptr_t` (64-bit) fields that require 8-byte alignment.
pub const buf_align = 8;

/// Initializes a pairing context with the provided `buffer` and other parameters.
/// This `Pairing` instance owns the given memory.
///
Expand All @@ -11,7 +15,7 @@ const Self = @This();
/// - it does not have allocator in its api
/// - can use stack allocation at consumer side
/// - can reuse memory if it makes sense at consumer side
pub fn init(buffer: *[Self.sizeOf()]u8, hash_or_encode: bool, dst: []const u8) Self {
pub fn init(buffer: *align(buf_align) [Self.sizeOf()]u8, hash_or_encode: bool, dst: []const u8) Self {
const obj = Self{ .ctx = @ptrCast(buffer) };
c.blst_pairing_init(obj.ctx, hash_or_encode, @ptrCast(dst.ptr), dst.len);

Expand Down Expand Up @@ -129,12 +133,10 @@ pub fn asFp12(self: *Self) *c.blst_fp12 {
}

test "init Pairing" {
const allocator = std.testing.allocator;
const buffer = try allocator.alloc(u8, @This().sizeOf());
defer allocator.free(buffer);
var buffer: [sizeOf()]u8 align(buf_align) = undefined;

const dst = "destination";
_ = @This().init(@ptrCast(buffer), true, dst);
_ = @This().init(&buffer, true, dst);
}

test "sizeOf Pairing" {
Expand Down
8 changes: 4 additions & 4 deletions src/Signature.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -61,7 +61,7 @@ pub fn verify(
pub fn aggregateVerify(
self: *const Self,
sig_groupcheck: bool,
buffer: *[Pairing.sizeOf()]u8,
buffer: *align(Pairing.buf_align) [Pairing.sizeOf()]u8,
msgs: []const [32]u8,
dst: []const u8,
pks: []const PublicKey,
Expand Down Expand Up @@ -105,7 +105,7 @@ pub fn aggregateVerify(
pub fn fastAggregateVerify(
self: *const Self,
sig_groupcheck: bool,
buffer: *[Pairing.sizeOf()]u8,
buffer: *align(Pairing.buf_align) [Pairing.sizeOf()]u8,
msg: *const [32]u8,
dst: []const u8,
pks: []const PublicKey,
Expand All @@ -130,7 +130,7 @@ pub fn fastAggregateVerify(
pub fn fastAggregateVerifyPreAggregated(
self: *const Self,
sig_groupcheck: bool,
buffer: *[Pairing.sizeOf()]u8,
buffer: *align(Pairing.buf_align) [Pairing.sizeOf()]u8,
msg: *const [32]u8,
dst: []const u8,
pk: *const PublicKey,
Expand Down Expand Up @@ -264,7 +264,7 @@ test aggregateVerify {

const num_sigs = 10;

var buffer: [3192]u8 = undefined;
var buffer: [Pairing.sizeOf()]u8 align(Pairing.buf_align) = undefined;

var msgs: [num_sigs][32]u8 = undefined;
var sks: [num_sigs]SecretKey = undefined;
Expand Down
2 changes: 1 addition & 1 deletion src/fast_verify.zig
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Expand Up @@ -10,7 +10,7 @@ const RAND_BITS = 8 * RAND_BYTES;
///
/// Returns true if verification succeeds, false if verification fails, `BlstError` on error.
pub fn verifyMultipleAggregateSignatures(
pairing_buf: *[Pairing.sizeOf()]u8,
pairing_buf: *align(Pairing.buf_align) [Pairing.sizeOf()]u8,
n_elems: usize,
msgs: []const [32]u8,
dst: []const u8,
Expand Down
6 changes: 3 additions & 3 deletions test/spec/test_case.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -85,7 +85,7 @@ pub fn aggregate_verify(gpa: Allocator, path: std.fs.Dir) !void {

var pk_buf: [blst.PublicKey.COMPRESS_SIZE]u8 = undefined;
var sig_buf: [blst.Signature.COMPRESS_SIZE]u8 = undefined;
var pairing_buf: [blst.Pairing.sizeOf()]u8 = undefined;
var pairing_buf: [blst.Pairing.sizeOf()]u8 align(blst.Pairing.buf_align) = undefined;

for (aggregate_verify_test_data.input.pubkeys, 0..) |pk_hex_bytes, i| {
const pk_bytes = try std.fmt.hexToBytes(
Expand Down Expand Up @@ -155,7 +155,7 @@ pub fn fast_aggregate_verify(gpa: Allocator, path: std.fs.Dir) !void {
var msg_bytes: [32]u8 = undefined;
var pk_buf: [blst.PublicKey.COMPRESS_SIZE]u8 = undefined;
var sig_buf: [blst.Signature.COMPRESS_SIZE]u8 = undefined;
var pairing_buf: [blst.Pairing.sizeOf()]u8 = undefined;
var pairing_buf: [blst.Pairing.sizeOf()]u8 align(blst.Pairing.buf_align) = undefined;

for (fast_aggregate_verify_test_data.input.pubkeys, 0..) |pk_hex_bytes, i| {
const pk_bytes = try std.fmt.hexToBytes(
Expand Down Expand Up @@ -381,7 +381,7 @@ pub fn eth_fast_aggregate_verify(gpa: Allocator, path: std.fs.Dir) !void {
var msg_bytes: [32]u8 = undefined;
var pk_buf: [blst.PublicKey.COMPRESS_SIZE]u8 = undefined;
var sig_buf: [blst.Signature.COMPRESS_SIZE]u8 = undefined;
var pairing_buf: [blst.Pairing.sizeOf()]u8 = undefined;
var pairing_buf: [blst.Pairing.sizeOf()]u8 align(blst.Pairing.buf_align) = undefined;

for (eth_fast_aggregate_verify_test_data.input.pubkeys, 0..) |pk_hex_bytes, i| {
const pk_bytes = try std.fmt.hexToBytes(
Expand Down