51 lines
2.3 KiB
Diff
51 lines
2.3 KiB
Diff
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Jeroen Hofstee <jhofstee@victronenergy.com>
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Date: Tue, 1 Apr 2025 20:09:31 +0000
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Subject: zlib: fix pointer alignment
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The function AllocForBrotli prefixes the allocated memory with its
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size, and returns a pointer to the region after it. This pointer can
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however no longer be suitably aligned. Correct this by allocating
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the maximum of the the size of the size_t and the max alignment.
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On Arm 32bits the size_t is 4 bytes long, but the alignment is 8 for
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some NEON instructions. When Brotli is compiled with optimizations
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enabled newer GCC versions will use the NEON instructions and trigger
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a bus error killing node.
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see https://github.com/google/brotli/issues/1159
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diff --git a/src/node_zlib.cc b/src/node_zlib.cc
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index 90307cd4984ae5aa55386f2980ad9cd540322dfd..6f12b5034d1a98da50c064cf2cfdf12fc88137eb 100644
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--- a/src/node_zlib.cc
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+++ b/src/node_zlib.cc
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@@ -493,7 +493,8 @@ class CompressionStream : public AsyncWrap, public ThreadPoolWork {
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}
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static void* AllocForBrotli(void* data, size_t size) {
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- size += sizeof(size_t);
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+ constexpr size_t offset = std::max(sizeof(size_t), alignof(max_align_t));
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+ size += offset;
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CompressionStream* ctx = static_cast<CompressionStream*>(data);
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char* memory = UncheckedMalloc(size);
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if (memory == nullptr) [[unlikely]] {
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@@ -502,7 +503,7 @@ class CompressionStream : public AsyncWrap, public ThreadPoolWork {
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*reinterpret_cast<size_t*>(memory) = size;
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ctx->unreported_allocations_.fetch_add(size,
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std::memory_order_relaxed);
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- return memory + sizeof(size_t);
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+ return memory + offset;
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}
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static void FreeForZlib(void* data, void* pointer) {
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@@ -510,7 +511,8 @@ class CompressionStream : public AsyncWrap, public ThreadPoolWork {
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return;
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}
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CompressionStream* ctx = static_cast<CompressionStream*>(data);
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- char* real_pointer = static_cast<char*>(pointer) - sizeof(size_t);
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+ constexpr size_t offset = std::max(sizeof(size_t), alignof(max_align_t));
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+ char* real_pointer = static_cast<char*>(pointer) - offset;
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size_t real_size = *reinterpret_cast<size_t*>(real_pointer);
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ctx->unreported_allocations_.fetch_sub(real_size,
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std::memory_order_relaxed);
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