On Sun, Mar 26, 2023 at 12:01 PM Paul Smith <p...@mad-scientist.net> wrote: > > OK here's something super-strange I discovered: > > Enabling -faddress=sanitize in GCC, causes the glob(3) function to > misbehave. > > I'm using GCC 11.3 / glibc 2.35 (x86_64 native). I have this simple > program:
Maybe https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88054 . Thanks, Andrew > > $ cat /tmp/tstglob.c > #include <stdio.h> > #include <glob.h> > > int main(int argc, char *argv[]) > { > glob_t gl = {0}; > int res = glob(argv[1], 0, NULL, &gl); > > switch (res) > { > case 0: printf("success\n"); break; > case GLOB_NOMATCH: printf("no match\n"); break; > default: printf("unknown: %d\n", res); break; > } > > return 0; > } > > Now I create a symlink that doesn't point to anything: > > $ ln -s nosuchfile /tmp/badlink > $ ls -al /tmp/badlink > lrwxrwxrwx 1 pds pds 10 Mar 26 14:52 /tmp/badlink -> nosuchfile > > Now I compile the above program normally and run it: > > $ gcc -o /tmp/tstglob /tmp/tstglob.c > $ /tmp/tstglob /tmp/badlink > success > > This is what I expect: the symlink does exist even though it doesn't > point to anything so glob() should return it. > > But now if I compile with ASAN: > > $ gcc -fsanitize=address -o /tmp/tstglob /tmp/tstglob.c > $ /tmp/tstglob /tmp/badlink > no match > > ...?!?!?! > > Is there something in the ASAN library that takes over glob(3) and > installs a different version (there have been plenty of versions of > glob(3) over the years in glibc which behave incorrectly when faced > with broken symlinks, heavens knows...) that overrides the glibc > version? > > Or...??
