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64 lines
2.6 KiB
64 lines
2.6 KiB
From 2a3129365d3bc0d4a41f107ef175920d1505d1f7 Mon Sep 17 00:00:00 2001 |
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From: Chris Liddell <chris.liddell@artifex.com> |
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Date: Tue, 1 Jun 2021 19:57:16 +0100 |
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Subject: [PATCH] Bug 703902: Fix op stack management in |
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sampled_data_continue() |
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Replace pop() (which does no checking, and doesn't handle stack extension |
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blocks) with ref_stack_pop() which does do all that. |
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We still use pop() in one case (it's faster), but we have to later use |
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ref_stack_pop() before calling sampled_data_sample() which also accesses the |
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op stack. |
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Fixes: |
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https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=34675 |
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--- |
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psi/zfsample.c | 16 ++++++++++------ |
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1 file changed, 10 insertions(+), 6 deletions(-) |
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diff --git a/psi/zfsample.c b/psi/zfsample.c |
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index 0e8e4bc8d..00cd0cfdd 100644 |
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--- a/psi/zfsample.c |
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+++ b/psi/zfsample.c |
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@@ -533,15 +533,19 @@ sampled_data_continue(i_ctx_t *i_ctx_p) |
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for (j = 0; j < bps; j++) |
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data_ptr[bps * i + j] = (byte)(cv >> ((bps - 1 - j) * 8)); /* MSB first */ |
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} |
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- pop(num_out); /* Move op to base of result values */ |
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- /* Check if we are done collecting data. */ |
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+ pop(num_out); /* Move op to base of result values */ |
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+ /* From here on, we have to use ref_stack_pop() rather than pop() |
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+ so that it handles stack extension blocks properly, before calling |
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+ sampled_data_sample() which also uses the op stack. |
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+ */ |
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+ /* Check if we are done collecting data. */ |
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if (increment_cube_indexes(params, penum->indexes)) { |
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if (stack_depth_adjust == 0) |
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- pop(O_STACK_PAD); /* Remove spare stack space */ |
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+ ref_stack_pop(&o_stack, O_STACK_PAD); /* Remove spare stack space */ |
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else |
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- pop(stack_depth_adjust - num_out); |
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+ ref_stack_pop(&o_stack, stack_depth_adjust - num_out); |
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/* Execute the closing procedure, if given */ |
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code = 0; |
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if (esp_finish_proc != 0) |
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@@ -554,11 +558,11 @@ sampled_data_continue(i_ctx_t *i_ctx_p) |
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if ((O_STACK_PAD - stack_depth_adjust) < 0) { |
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stack_depth_adjust = -(O_STACK_PAD - stack_depth_adjust); |
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check_op(stack_depth_adjust); |
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- pop(stack_depth_adjust); |
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+ ref_stack_pop(&o_stack, stack_depth_adjust); |
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} |
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else { |
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check_ostack(O_STACK_PAD - stack_depth_adjust); |
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- push(O_STACK_PAD - stack_depth_adjust); |
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+ ref_stack_push(&o_stack, O_STACK_PAD - stack_depth_adjust); |
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for (i=0;i<O_STACK_PAD - stack_depth_adjust;i++) |
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make_null(op - i); |
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} |
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-- |
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2.35.1 |
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