Package: libc6
Version: 2.24-12
Tags: upstream patch
Forwarded: https://sourceware.org/ml/libc-alpha/2017-07/msg00466.html
User: debian-68k@lists.debian.org
Usertags: m68k
X-Debbugs-Cc: debian-68k@lists.debian.org
Hi,
On m68k, gethostbyname can sometimes cause an assertion failure:
> "nss_files/files-hosts.c:218: _nss_files_gethostbyname3_r: Assertion
> `(bufferend - (char *) 0) % sizeof (char *) == 0' failed."
This can be reproduced with the following simple program (though it may
depend on the exact system or chroot setup):
> #include <stdio.h>
> #include <netdb.h>
>
> int main(int argc, char **argv) {
> struct hostent *h = gethostbyname("localhost");
> printf("name: %s\n", h->h_name);
> return 0;
> }
This is because _nss_files_gethostbyname3_r asserts that bufferend is
sizeof-aligned (4 bytes for a char *), but parse_list only rounds to
__alignof__(char *), which is (unusually) just 2 bytes on m68k. The
above patch forwarded upstream weakens the assertion (and subsequent
rounding on future loop iterations) to only be __alignof__(char *).
Regards,
James
