48 lines
1.5 KiB
Diff
48 lines
1.5 KiB
Diff
From 3831354113db8803fb1f5ba196cf0bbb537578dd Mon Sep 17 00:00:00 2001
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From: Garret Rieger <grieger@google.com>
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Date: Thu, 31 May 2018 17:54:06 -0700
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Subject: [PATCH] [subset] Check for overflow when decoding glyf.
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---
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src/woff2_dec.cc | 19 ++++++++++++++++---
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1 file changed, 16 insertions(+), 3 deletions(-)
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diff --git a/src/woff2_dec.cc b/src/woff2_dec.cc
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index 8186c8e..25e18c6 100644
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--- a/src/woff2_dec.cc
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+++ b/src/woff2_dec.cc
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@@ -111,6 +111,16 @@ int WithSign(int flag, int baseval) {
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return (flag & 1) ? baseval : -baseval;
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}
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+bool _SafeIntAddition(int a, int b, int* result) {
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+ if (PREDICT_FALSE(
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+ ((a > 0) && (b > std::numeric_limits<int>::max() - a)) ||
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+ ((a < 0) && (b < std::numeric_limits<int>::min() - a)))) {
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+ return false;
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+ }
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+ *result = a + b;
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+ return true;
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+}
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+
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bool TripletDecode(const uint8_t* flags_in, const uint8_t* in, size_t in_size,
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unsigned int n_points, Point* result, size_t* in_bytes_consumed) {
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int x = 0;
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@@ -166,9 +176,12 @@ bool TripletDecode(const uint8_t* flags_in, const uint8_t* in, size_t in_size,
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(in[triplet_index + 2] << 8) + in[triplet_index + 3]);
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}
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triplet_index += n_data_bytes;
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- // Possible overflow but coordinate values are not security sensitive
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- x += dx;
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- y += dy;
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+ if (!_SafeIntAddition(x, dx, &x)) {
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+ return false;
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+ }
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+ if (!_SafeIntAddition(y, dy, &y)) {
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+ return false;
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+ }
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*result++ = {x, y, on_curve};
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}
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*in_bytes_consumed = triplet_index;
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