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Summary: Variable-length array (VLA) should have a size that fits into a size_t value. According to the standard: "std::size_t can store the maximum size of a theoretically possible object of any type (including array)" (this is applied to C too). The size expression is evaluated at the definition of the VLA type even if this is a typedef. The evaluation of the size expression in itself might cause problems if it overflows. Reviewers: Szelethus, baloghadamsoftware, martong, gamesh411 Reviewed By: Szelethus, martong, gamesh411 Subscribers: whisperity, rnkovacs, xazax.hun, baloghadamsoftware, szepet, a.sidorin, mikhail.ramalho, Szelethus, donat.nagy, dkrupp, gamesh411, Charusso, martong, ASDenysPetrov, cfe-commits Tags: #clang Differential Revision: https://reviews.llvm.org/D79330
26 lines
825 B
C
26 lines
825 B
C
// RUN: %clang_analyze_cc1 -triple x86_64-pc-linux-gnu -analyzer-checker=core -verify %s
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typedef unsigned long size_t;
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#define BIGINDEX 65536U
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size_t check_VLA_overflow_sizeof(unsigned int x) {
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if (x == BIGINDEX) {
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// We expect here that size_t is a 64 bit value.
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// Size of this array should be the first to overflow.
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size_t s = sizeof(char[x][x][x][x]); // expected-warning{{Declared variable-length array (VLA) has too large size [core.VLASize]}}
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return s;
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}
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return 0;
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}
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void check_VLA_overflow_typedef() {
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unsigned int x = BIGINDEX;
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typedef char VLA[x][x][x][x]; // expected-warning{{Declared variable-length array (VLA) has too large size [core.VLASize]}}
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}
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void check_VLA_no_overflow() {
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unsigned int x = BIGINDEX;
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typedef char VLA[x][x][x][x - 1];
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typedef char VLA1[0xffffffffu];
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}
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