leading whitespace in ACF is a syntax error/crash

[mdavidsaver]

Leading whitespace in a comment line of an ACF file is apparently a syntax error, and in <=3.15.3 causes ascheck to crash w/ buffer overflow detected.

I'll attach an offending example.

[mdavidsaver (mdavidsaver)]

Example ACF file attached

w/ 3.16 current

> $ ./bin/linux-x86_64-debug/ascheck bad.acf
> invalid character '#'
> Access Security file error at line 3
> syntax error
> Access Security file error at line 3
> ascheck: Access Security File failed.

With 3.15.3

> $ ascheck bad.acf
> *** buffer overflow detected ***: ascheck terminated
> ======= Backtrace: =========
> /lib/x86_64-linux-gnu/libc.so.6(+0x731af)[0x7fe04440c1af]
> /lib/x86_64-linux-gnu/libc.so.6(__fortify_fail+0x37)[0x7fe044491aa7]
> /lib/x86_64-linux-gnu/libc.so.6(+0xf6cc0)[0x7fe04448fcc0]
> /lib/x86_64-linux-gnu/libc.so.6(+0xf61c9)[0x7fe04448f1c9]
> /lib/x86_64-linux-gnu/libc.so.6(_IO_vfprintf+0x55eb)[0x7fe0443e47ab]
> /lib/x86_64-linux-gnu/libc.so.6(__vsprintf_chk+0x88)[0x7fe04448f258]
> /lib/x86_64-linux-gnu/libc.so.6(__sprintf_chk+0x7d)[0x7fe04448f1ad]
> /usr/lib/x86_64-linux-gnu/libCom.so.3.15.3(+0x2515c)[0x7fe04476915c]
> /usr/lib/x86_64-linux-gnu/libCom.so.3.15.3(asInitialize+0xae0)[0x7fe04476a970]
> /usr/lib/x86_64-linux-gnu/libCom.so.3.15.3(asInitFP+0xb0)[0x7fe04476b180]
> /usr/lib/x86_64-linux-gnu/libCom.so.3.15.3(asInitFile+0x29)[0x7fe04476b239]
> ascheck(main+0x114)[0x400a54]

[mdavidsaver (mdavidsaver)]

I remember seeing this w/ 3.14 as well. Should have reported it long ago...

[mdavidsaver (mdavidsaver)]

asLib_lex.l contains the pattern

> ^#.*

I think that simply removing the '^' is sufficient to allow the parser to tolerate whitespace (and non-whitespace) before '#'.

I think, but haven't verified, that the crash has already been fixed in 3.14.12.6 and 3.15.5 with 54381b7bf946379d4dbb441adacd21a593fb4433

[Andrew Johnson (anj)]

The 54381b7bf946379d4dbb441adacd21a593fb4433 commit couldn't fix this problem in asLib, it only modified the dbStatic parser which is separate code. However in addition to allowing whitespace before comments I've made an equivalent modifications to handle invalid characters in the asLib parser, and improved the error messages displayed.