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platform_system_core
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Fix an error when overflows occur. 

Bug: 169657723

Test: Ran original test case and verified it does not leak.
Change-Id: I7a315bc3a2c380c207696ce06cc4aeb5b27937ac
This commit is contained in:
Christopher Ferris 2020-10-01 18:39:33 -07:00
parent 8ba33eb34b
commit 9b6abd50d8
1 changed files with 21 additions and 5 deletions
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26
libunwindstack/tests/fuzz/UnwinderComponentCreator.cpp
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@ -116,8 +116,12 @@ ElfFake* PopulateElfFake(FuzzedDataProvider* data_provider) {
static constexpr size_t kPageSize = 4096;
static constexpr uint64_t AlignToPage(uint64_t address) {
return (address + kPageSize - 1) & ~(kPageSize - 1);
static inline bool AlignToPage(uint64_t address, uint64_t* aligned_address) {
if (__builtin_add_overflow(address, kPageSize - 1, aligned_address)) {
return false;
}
*aligned_address &= ~(kPageSize - 1);
return true;
}
std::unique_ptr<Maps> GetMaps(FuzzedDataProvider* data_provider) {
@ -125,8 +129,16 @@ std::unique_ptr<Maps> GetMaps(FuzzedDataProvider* data_provider) {
std::map<uint64_t, uint64_t> map_ends;
uint8_t entry_count = data_provider->ConsumeIntegralInRange<uint8_t>(0, kMaxMapEntryCount);
for (uint8_t i = 0; i < entry_count; i++) {
uint64_t start = AlignToPage(data_provider->ConsumeIntegral<uint64_t>());
uint64_t end = AlignToPage(data_provider->ConsumeIntegralInRange<uint64_t>(start, UINT64_MAX));
uint64_t start;
if (!AlignToPage(data_provider->ConsumeIntegral<uint64_t>(), &start)) {
// Overflowed.
continue;
}
uint64_t end;
if (!AlignToPage(data_provider->ConsumeIntegralInRange<uint64_t>(start, UINT64_MAX), &end)) {
// Overflowed.
continue;
}
if (start == end) {
// It's impossible to see start == end in the real world, so
// make sure the map contains at least one page of data.
@ -142,7 +154,11 @@ std::unique_ptr<Maps> GetMaps(FuzzedDataProvider* data_provider) {
}
map_ends[end] = start;
uint64_t offset = AlignToPage(data_provider->ConsumeIntegral<uint64_t>());
uint64_t offset;
if (!AlignToPage(data_provider->ConsumeIntegral<uint64_t>(), &offset)) {
// Overflowed.
continue;
}
std::string map_info_name = data_provider->ConsumeRandomLengthString(kMaxMapInfoNameLen);
uint8_t flags = PROT_READ | PROT_WRITE;