Fix find info resp when called on non-descriptor attributes #148
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src/utility/ATT.cpp
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| @@ -683,7 +683,8 @@ void ATTClass::findInfoReq(uint16_t connectionHandle, uint16_t mtu, uint8_t dlen | |||
| BLELocalAttribute* attribute = GATT.attribute(i); | |||
| uint16_t handle = (i + 1); | |||
| bool isValueHandle = (attribute->type() == BLETypeCharacteristic) && (((BLELocalCharacteristic*)attribute)->valueHandle() == handle); | |||
| int uuidLen = isValueHandle ? 2 : attribute->uuidLength(); | |||
| bool isDescriptor = attribute->type() == BLETypeDescriptor; | |||
| int uuidLen = isValueHandle ? 2 : (isDescriptor ? attribute->uuidLength() : BLE_ATTRIBUTE_TYPE_SIZE); | |||
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I don't think this is correct. If it's a value handle, it should use the attribute's UUID length right?
If we align it with the if logic on 703, value and descriptor handles memcpy the UUID data, so the uuidLen should reflect as such. Otherwise use the type size of 2
int uuidLen = (isValueHandle || isDescriptor) ? attribute->uuidLength() : BLE_ATTRIBUTE_TYPE_SIZE;
// also can update the if on 703 to match
if (isValueHandle || isDescriptor) {
// add the UUID
} else {
// add the type
}There was a problem hiding this comment.
Yes you're definitely right!
I'm going to update the PR
Before this fix, if the 'ATT information request' was called on an handle belonging to a non-descriptor attribute, then the response would contain the uuid of the actual attribute's type but with the format of the attribute uuid (0x01 for 16 bit length, 0x02 for 128 bit length). So, for instance, if the info request was performed on an handle belonging to a service with a uuid of 128 bit, then the response would have been malformed because the size of the attribute's type is 16 bit.
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ThomasGerstenberg
approved these changes
Dec 12, 2020
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Before this fix, if the
ATT information requestwas called on an handle belonging to a non-descriptor attribute, then the response would contain the uuid of the actual attribute's type but with the format of the attribute uuid (0x01 for 16 bit length, 0x02 for 128 bit length).So, for instance, if the info request was performed on an handle belonging to a service with a uuid of 128 bit, then the response would have been malformed because the size of the attribute's type is 16 bit.
From issue discovered by @ThomasGerstenberg
#147