Aws-sdk-cpp: Signed integer overflow

[mihaimaruseac]

https://github.com/aws/aws-sdk-cpp/blob/5eef9454a4048258b68de0402d6e02a20c91942f/aws-cpp-sdk-core/source/utils/HashingUtils.cpp#L240

external/aws/aws-cpp-sdk-core/source/utils/HashingUtils.cpp:240:31: runtime error: signed integer overflow: 31 * 94752355 cannot be represented in type 'int'
    #0 0x534115c in Aws::Utils::HashingUtils::HashString(char const*) /proc/self/cwd/external/aws/aws-cpp-sdk-core/source/utils/HashingUtils.cpp:240:31                     
    #1 0x5c4025 in __cxx_global_var_init /proc/self/cwd/external/aws/aws-cpp-sdk-s3/source/S3Endpoint.cpp:29:37                                                                              
    #2 0x5c40e0 in _GLOBAL__sub_I_S3Endpoint.cpp /proc/self/cwd/external/aws/aws-cpp-sdk-s3/source/S3Endpoint.cpp
    #3 0x5d22e6c in __libc_csu_init (/out/parse_tensor_op_fuzz+0x5d22e6c)
    #4 0x7f8dec90a7be in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x207be)                            
    #5 0x5cf288 in _start (/out/parse_tensor_op_fuzz+0x5cf288)

[singku]

Did you compile the SDK with sanitizer? That piece of code is to compute hash, overflow is intended.

[mihaimaruseac]

Yes, I am fuzzing tensorflow on OSSFuzz and it detected an overflow on the dependency.

Signed integer overflow is undefined behavior, we should make it explicit if we rely on it.

[Matheus28]

The ideal would be making it unsigned so it's not undefined behavior

[wps132230]

@Matheus28 Thank you for your suggestion, and we've changed it to unsigned: https://github.com/aws/aws-sdk-cpp/commit/f750d60ca1b950301cd16bb6e8a39a8af615f872