Re: segfault on ENVIRON access (5.1.1 but NOT in latest git)

[arnold]

Hi.

Thank you for reporting a bug. This issue was reported recently and that's
why it's fixed in Git master.  I'm working on a new release, so that release
will have the fix in it.

Much thanks,

Arnold

Mathieu Bivert <mathieu.bivert@gmail.com> wrote:

> Hello,
>
>   I've hit a systematically reproducible segfault on ENVIRON access
> on gawk-5.1.1, but not anymore with the latest git commit (381d737c).
>
> I haven't looked too deep into the changelog/mailing list to see if it's
> actually relevant; I prefer to notify you, just in case there's something
> else lurking around.
>
> Segfault occurs, among others, when **environ starts with a variable
> named 0 (zero):
>
>     % uname -a
>     Linux earth 5.17.9-arch1-1 #1 SMP PREEMPT Wed, 18 May 2022 17:30:11
> +0000 x86_64 GNU/Linux
>     % cat test.c && cc test.c && echo | ./a.out
>     #include <stdio.h>
>     #include <stdlib.h>
>     #include <unistd.h>
>     #include <string.h>
>
>     extern char **environ;
>
>     char *gawk = "/home/mb/src/gawk-5.1.1/gawk";
>
>     int main(void)
>     {
>         char *argv[] = {
>             "gawk",
>             "{\n\
>                 for (k in ENVIRON)\n\
>                     printf(\"ENV[%s] = %s\\n\", k, ENVIRON[k])\n\
>             }",
>             NULL
>         };
>
>         /* assuming environ contains at least one variable */
>         environ[0] = strdup("0=whatever");
>         if (environ[0] == NULL) {
>             perror("strdup()");
>             return -1;
>         }
>
>         execv(gawk, argv);
>         return 0;
>     }
>     gawk: cmd. line:2: (FILENAME=- FNR=1) fatal error: internal error:
> segfault
>     Aborted (core dumped)
>
> Cheers,