[memory/cryptolib] Launder status output #28810
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Since the hardened memory operations just return OTCRYPTO_OK the compiler optimizes the status output which circumvents the control flow integrity. An example is 20011276: | | 9e2080e7 jalr -1566(ra) # 2002bc54 <hardened_memcpy> 2001127a: | | 73900513 li a0,1849 Launder the status output to circumvent this. Once there is another call in place which makes the possibility to return a different status, this launder is no longer needed. The assembly files were checked for similar patterns, only a single call in RSA had a similar result. Signed-off-by: Siemen Dhooghe <[email protected]>
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Since the hardened memory operations just return OTCRYPTO_OK the compiler optimizes the status output which circumvents the control flow integrity. An example is
20011276: | | 9e2080e7 jalr
-1566(ra) # 2002bc54 <hardened_memcpy>
2001127a: | | 73900513 li
a0,1849
Launder the status output to circumvent this. Once there is another call in place which makes the possibility to return a different status, this launder is no longer needed.
The assembly files were checked for similar patterns, only a single call in RSA had a similar result.