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author | Christopher Ferris <cferris@google.com> | 2015-05-06 16:36:34 -0700 |
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committer | Christopher Ferris <cferris@google.com> | 2015-05-06 19:08:52 -0700 |
commit | 8bd4a4ecdc48ead03ca4e90ad585324bcd63b9f0 (patch) | |
tree | efcd32fdaab3d283b2148e9d8829e675a72aa358 /libbacktrace/backtrace_test.cpp | |
parent | af67fb247540ef084a0b644e1d3bf225db4de6bd (diff) | |
download | system_core-8bd4a4ecdc48ead03ca4e90ad585324bcd63b9f0.tar.gz system_core-8bd4a4ecdc48ead03ca4e90ad585324bcd63b9f0.tar.bz2 system_core-8bd4a4ecdc48ead03ca4e90ad585324bcd63b9f0.zip |
Fix small ptrace reads.
The BacktracePtrace::Read function crashes if the number of bytes to
read is less than the number of bytes needed to align the read to
a word_t boundary.
Fix this and add a test for this case.
Change-Id: I50808849ece44928f65dba1d25309e3885c829a2
(cherry picked from commit 944f417ccb86441060ffb670b4bdc2975fda08fc)
Diffstat (limited to 'libbacktrace/backtrace_test.cpp')
-rw-r--r-- | libbacktrace/backtrace_test.cpp | 38 |
1 files changed, 29 insertions, 9 deletions
diff --git a/libbacktrace/backtrace_test.cpp b/libbacktrace/backtrace_test.cpp index ebcb1f888..ba3cbb58d 100644 --- a/libbacktrace/backtrace_test.cpp +++ b/libbacktrace/backtrace_test.cpp @@ -882,6 +882,17 @@ TEST(libbacktrace, verify_map_remote) { ASSERT_EQ(waitpid(pid, nullptr, 0), pid); } +void InitMemory(uint8_t* memory, size_t bytes) { + for (size_t i = 0; i < bytes; i++) { + memory[i] = i; + if (memory[i] == '\0') { + // Don't use '\0' in our data so we can verify that an overread doesn't + // occur by using a '\0' as the character after the read data. + memory[i] = 23; + } + } +} + void* ThreadReadTest(void* data) { thread_t* thread_data = reinterpret_cast<thread_t*>(data); @@ -900,9 +911,7 @@ void* ThreadReadTest(void* data) { } // Set up a simple pattern in memory. - for (size_t i = 0; i < pagesize; i++) { - memory[i] = i; - } + InitMemory(memory, pagesize); thread_data->data = memory; @@ -930,9 +939,8 @@ void RunReadTest(Backtrace* backtrace, uintptr_t read_addr) { // Create a page of data to use to do quick compares. uint8_t* expected = new uint8_t[pagesize]; - for (size_t i = 0; i < pagesize; i++) { - expected[i] = i; - } + InitMemory(expected, pagesize); + uint8_t* data = new uint8_t[2*pagesize]; // Verify that we can only read one page worth of data. size_t bytes_read = backtrace->Read(read_addr, data, 2 * pagesize); @@ -946,6 +954,20 @@ void RunReadTest(Backtrace* backtrace, uintptr_t read_addr) { ASSERT_TRUE(memcmp(data, &expected[i], 2 * sizeof(word_t)) == 0) << "Offset at " << i << " failed"; } + + // Verify small unaligned reads. + for (size_t i = 1; i < sizeof(word_t); i++) { + for (size_t j = 1; j < sizeof(word_t); j++) { + // Set one byte past what we expect to read, to guarantee we don't overread. + data[j] = '\0'; + bytes_read = backtrace->Read(read_addr + i, data, j); + ASSERT_EQ(j, bytes_read); + ASSERT_TRUE(memcmp(data, &expected[i], j) == 0) + << "Offset at " << i << " length " << j << " miscompared"; + ASSERT_EQ('\0', data[j]) + << "Offset at " << i << " length " << j << " wrote too much data"; + } + } delete data; delete expected; } @@ -989,9 +1011,7 @@ void ForkedReadTest() { } // Set up a simple pattern in memory. - for (size_t i = 0; i < pagesize; i++) { - memory[i] = i; - } + InitMemory(memory, pagesize); g_addr = reinterpret_cast<uintptr_t>(memory); g_ready = 1; |