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openenclave / oeedger8r-cpp

An implementation of oeedger8r in C++
MIT License
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Add OE_ADD_ARG_SIZE macro #70

Closed mingweishih closed 3 years ago

mingweishih commented 3 years ago

Address comments from https://github.com/openenclave/openenclave/pull/3831

Signed-off-by: Ming-Wei Shih mishih@microsoft.com

mingweishih commented 3 years ago

@CodeMonkeyLeet Can you take a look? We need to retain OE_COMPUTE_ARG_SIZE. If we use OE_ADD_ARG_SIZE to calculate _size (say argcount=1, argsize=4), OE_ADD will apply the alignment (16) to the result, making the _size become 16 instead 4. This will cause memory overwritten in memcpy.

#define OE_READ_OUT_PARAM(argname, argcount, argsize)                          \
    if (argname)                                                               \
    {                                                                          \
        size_t _size = 0;                                                      \
        OE_COMPUTE_ARG_SIZE(_size, argcount, argsize);                         \
        memcpy((void*)argname, _output_buffer + _output_buffer_offset, _size); \
        OE_ADD_SIZE(_output_buffer_offset, _size);                             \
    }
oe-ci-robot commented 3 years ago

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: CodeMonkeyLeet, mingweishih

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