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Change build info short-length to be based on real length.

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[ Cherry-pick of v19 http://go/wvgerrit/219592 ]
[ Merge of http://go/wvgerrit/219554 ]

The original CheckBuildInformation_OutputLengthAPI17 test was
written with the assumption that the estimated length would not
be too much larger than the real length of the build info; however
this is not true for some vendors.

This CL changes the short-buffer length to be based on a real
build info length from a successful call to OEMCrypto.

Bug: 411308060
Change-Id: I6504288ca59d7d41facaadc45adc76a5236826d9
This commit is contained in:
Alex Dale
2025-04-21 15:58:05 -07:00
parent 961faf0729
commit 2a6154617f
1 changed files with 28 additions and 15 deletions
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43
libwvdrmengine/oemcrypto/test/oemcrypto_basic_test.cpp
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@@ -399,45 +399,58 @@ TEST_F(OEMCryptoClientTest, CheckBuildInformation_OutputLengthAPI17) {
ASSERT_GT(build_info_length, kZero) ASSERT_GT(build_info_length, kZero)
<< "Signaling ERROR_SHORT_BUFFER should have assigned a length"; << "Signaling ERROR_SHORT_BUFFER should have assigned a length";
// Try again using the size they provided, ensuring that it
// is successful.
const size_t initial_estimate_length = build_info_length;
build_info.assign(build_info_length, kNullChar);
result = OEMCrypto_BuildInformation(&build_info[0], &build_info_length);
ASSERT_EQ(result, OEMCrypto_SUCCESS)
<< "initial_estimate_length = " << initial_estimate_length
<< ", build_info_length (output) = " << build_info_length;
ASSERT_GT(build_info_length, kZero) << "Build info cannot be empty";
// Ensure the real length is within the size originally specified.
// OK if final length is smaller than estimated length.
ASSERT_LE(build_info_length, initial_estimate_length);
const size_t expected_length = build_info_length;
// Force a ERROR_SHORT_BUFFER using a non-zero value. // Force a ERROR_SHORT_BUFFER using a non-zero value.
// Note: It is assumed that vendors will provide more than a single // Note: It is assumed that vendors will provide more than a single
// character of info. // character of info.
const size_t second_attempt_length = const size_t short_length = (expected_length >= 2) ? expected_length / 2 : 1;
(build_info_length >= 2) ? build_info_length / 2 : 1; build_info.assign(short_length, kNullChar);
build_info.assign(second_attempt_length, kNullChar);
build_info_length = build_info.size(); build_info_length = build_info.size();
result = OEMCrypto_BuildInformation(&build_info[0], &build_info_length); result = OEMCrypto_BuildInformation(&build_info[0], &build_info_length);
ASSERT_EQ(result, OEMCrypto_ERROR_SHORT_BUFFER) ASSERT_EQ(result, OEMCrypto_ERROR_SHORT_BUFFER)
<< "second_attempt_length = " << second_attempt_length << "short_length = " << short_length
<< ", build_info_length" << build_info_length; << ", expected_length = " << expected_length << ", build_info_length"
<< build_info_length;
// OEM specified build info length should be larger than the // OEM specified build info length should be larger than the
// original length if returning ERROR_SHORT_BUFFER. // original length if returning ERROR_SHORT_BUFFER.
ASSERT_GT(build_info_length, second_attempt_length); ASSERT_GT(build_info_length, short_length);
// Final attempt with a buffer large enough buffer, padding to // Final attempt with a buffer large enough buffer, padding to
// ensure the caller truncates. // ensure the caller truncates.
constexpr size_t kBufferPadSize = 42; constexpr size_t kBufferPadSize = 42;
const size_t expected_length = build_info_length; const size_t oversize_length = expected_length + kBufferPadSize;
const size_t final_attempt_length = expected_length + kBufferPadSize; build_info.assign(oversize_length, kNullChar);
build_info.assign(final_attempt_length, kNullChar);
build_info_length = build_info.size(); build_info_length = build_info.size();
result = OEMCrypto_BuildInformation(&build_info[0], &build_info_length); result = OEMCrypto_BuildInformation(&build_info[0], &build_info_length);
ASSERT_EQ(result, OEMCrypto_SUCCESS) ASSERT_EQ(result, OEMCrypto_SUCCESS)
<< "final_attempt_length = " << final_attempt_length << "oversize_length = " << oversize_length
<< ", expected_length = " << expected_length << ", expected_length = " << expected_length
<< ", build_info_length = " << build_info_length; << ", build_info_length (output) = " << build_info_length;
// Ensure not empty. // Ensure not empty.
ASSERT_GT(build_info_length, kZero) << "Build info cannot be empty"; ASSERT_GT(build_info_length, kZero) << "Build info cannot be empty";
// Ensure it was truncated down from the padded length. // Ensure it was truncated down from the padded length.
ASSERT_LT(build_info_length, final_attempt_length) ASSERT_LT(build_info_length, oversize_length)
<< "Should have truncated from oversized buffer: expected_length = " << "Should have truncated from oversized buffer: expected_length = "
<< expected_length; << expected_length;
// Ensure the real length is within the size originally specified. // Ensure that length is equal to the length of the previous
// OK if final length is smaller than estimated length. // successful call.
ASSERT_LE(build_info_length, expected_length); ASSERT_EQ(build_info_length, expected_length);
} }
// Verifies that OEMCrypto_BuildInformation() is behaving as expected // Verifies that OEMCrypto_BuildInformation() is behaving as expected