PPC: fix out of bound memory access

[hamarituc]

Please review the patch carefully. It at least fixes an out of bound memory access. But I suppose the former as well as the new code doesn't produce the intended behavior. The variable name may contain condition register names like cr0, cr1, ..., but the code seems to be meant for condition register bits cr0eq, cr0gt, cr0lt, cr0un, ...

closes #1912

[kabeor]

Thanks for your contribution, plz add instruction test at https://github.com/capstone-engine/capstone/blob/next/suite/cstest/issues.cs

[hamarituc]

Thanks for your contribution, plz add instruction test at https://github.com/capstone-engine/capstone/blob/next/suite/cstest/issues.cs

Thanks for the remark.

Is there a way to set the CS_OPT_NOREGNAME option in the test? I tried with

!# issue 1912 PPC register name
!# CS_ARCH_PPC, CS_MODE_BIG_ENDIAN, None
0x2d,0x03,0x00,0x80 == cmpwi cr2, r3, 0x80

!# issue 1912 PPC no register name
!# CS_ARCH_PPC, CS_MODE_BIG_ENDIAN, CS_OPT_NOREGNAME
0x2d,0x03,0x00,0x80 == cmpwi 2, 3, 0x80

but the options are just comments. Without this possibility a test wouldn't make much sense, because there is no way to reproduce the failure conditions.

Even then, the test would not be accurate in detecting a regression as this patch fixes a memory corruption. This is not a deterministic behavior. Whether the test fails depends on the C library implementation, the order of memory allocation and releases, library versions etc. It makes more sense to identify such issues by running the regular test suite with -fsanitize=address. The issue was discovered that way by running the provided tests on a PowerPC machine.

[kabeor]

Is there a way to set the CS_OPT_NOREGNAME option in the test? I tried with

Acutally yes, there is a flag names CS_OPT_SYNTAX_NOREGNAME, refer here

[hamarituc]

Is there a way to set the CS_OPT_NOREGNAME option in the test? I tried with

Acutally yes, there is a flag names CS_OPT_SYNTAX_NOREGNAME, refer here

Thanks for the hint!

[kabeor]

Great, thanks for your contribution!