[Zlib-devel] [PATCH] Fix segfault when NULL is passed as path to gzopen*

[Mike Frysinger]

On Friday, February 04, 2011 06:42:18 Enrico Weigelt wrote:
> * Mike Frysinger <vapier at gentoo.org> schrieb:
> > On Wednesday, December 15, 2010 17:01:47 Ozgur Murat Homurlu wrote:
> > > In gz_open function, path parameter is passed to strlen() without
> > > checking. This causes a segmentation fault if path is passed as NULL.
> > 
> > here's an idea ... dont call gzopen() with NULL
> 
> Easier said than done. Your idea essentially requires every caller
> to ensure he doesn't pass NULL, to prevent unpredictable behaviour.

if you do fopen() and dont check the return, your code is stupid.  it's really 
not that hard to write non-stupid code.

> (unfortunately, in C we don't have something like an NOTNULL constraint, so
> the compiler could tell us here what's wrong)

gcc does provide for a non-null attribute, but obviously only works on 
constants.  it'd also be trivial to have a debug version of zlib.h that 
creates inlines which check all of its arguments and calls abort() before 
calling back into the actual zlib library.
-mike
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