The `cmsys/Enconding.h` include had a typo in its surrounding ifdef,
possibly causing a missing function declaration (`cmsysEncoding_DupToWide`).
As this is C code, this resulted in the code compiling, but with a truncated
return value, possibly causing crashes.
Extend the fix from commit v3.10.0-rc1~188^2 (ListFileLexer: fix
heap-buffer-overflow on malicious input, 2017-08-26) to apply to all
lexer token matches. Replace all `.` with `[^\0\n]`. Update all
`[^...]` match expressions to not match `\0`.
We cannot safely process null bytes in strings.
Fixes: #18124
In case a list file contains a null terminated string that is continued
until a later space, the lexer token information got inconsistent:
e.g. an argument "TEST\0FOOBAR" is passed by the lexer as a token
char* = "TEST\0FOOBAR" and length 11
^^ note: ascii 0x00
Using strdup in cmListFileLexer leads lexer->token.text to be allocated
with size 5 and lexer->token.length to be set to 11
A subsequent call to this function with an argument of 5 < length <= 11
wrongly assumed a sufficiently sized buffer and therefore corrupted the
heap buffer. The program might crash due to this corruption.
The case "NullTerminatedArgument" is intentionally using a quite large
'rest' to increase the chance to actually hit the issue. It will reliably
crash with address sanitizer enabled though.
This fix addresses all rules where arbitrary characters are matched to
ignore \0 in order to fall through to the rule that matches an arbitrary
character as BadCharacter.
Signed-off-by: Matthias Maennich <matthias@maennich.net>
flex 2.6.3 introduces symbol remapping through macro definitions. hence the
change appears bigger than one would expect from a minor version upgrade.
In addition some manual cleanup that had to be done previously is now
obsolete. namely:
- the size_t cast of _yybytes_len in yy_scan_bytes
(i is now also defined int and not size_t anymore)
- the redefinition of yyl within yy_find_action
(yyl is now already defined as int)
Line number preprocessor directives (#line) were previously generated into
the c source file. This actually breaks debugging as debuggers have a hard
time finding the original cmListFileLexer.in.l and mapping the current
instruction to a meaningful location within that file.
The prefix "cmListFileLexer_yy" can already be set as %option directly.
For convenience also provide a sed command for all the manual steps that
need to be done after generating.
Signed-off-by: Matthias Maennich <matthias@maennich.net>
