Hi,
On 2019-12-07 13:42, Felix Lechner wrote:
> Hi,
>
> Starting in `libc6 2.29-5`, the Lintian test
> `t/tags/checks/binaries/binaries-obsolete-des` fails in `unstable`:
>
> cc -g -O2
> -fdebug-prefix-map=/builds/lintian/lintian/debian/test-out/packages/tags/checks/binaries/binaries-obsolete-des/binaries-obsolete-des-1.0=.
> -fstack-protector-strong -Wformat -Werror=format-security -Wl,-z,relro
> -Wl,-z,now uses-fcrypt.o -o uses-fcrypt -lcrypt
> /usr/bin/ld: uses-fcrypt.o: in function `main':
> ./uses-fcrypt.c:19: undefined reference to `fcrypt'
> collect2: error: ld returned 1 exit status
> make[2]: *** [Makefile:34: uses-fcrypt] Error 1
Sorry about breaking lintian with that change.
> Perhaps is it time to remove the test (and the tag
> `obsolete-des-encryption`). Was `fcrypt` dropped entirely, or is it
> still provided by `libcrypt`?
Yes, fcrypt is still provided by libcrypt, and like libc it is
not available to newly linked binaries, just for old binaries. That's
why you need some tricks to link against it.
> I do not understand the impact of this commit:
>
>
> https://salsa.debian.org/glibc-team/glibc/commit/e1dc23943b0a5c9e0612f8e1364a37f12b6710ef
>
> Here is the code that did not link:
>
> /* This program uses the obsolete function 'fcrypt',
>which is an alias for 'crypt'. */
>
> #include
> #include
>
> /* The prototype may already have been removed from crypt.h. */
> extern char *fcrypt(const char *, const char *);
>
> /* It may already not be possible to link new programs that use
>'fcrypt' without special magic. */
> #ifdef SYMVER
> __asm__ (".symver fcrypt, fcrypt@" SYMVER);
> #endif
>
> int
> main(void)
> {
> puts(fcrypt("password", "Dn"));
> return 0;
> }
The code itself works. However for that it needs to have SYMVER defined
to the correct version. This is done in the Makefile, and it assumes
that libcrypto.so is provided by libc6. The following patch makes the
code to link correctly:
--- t/tags/checks/binaries/binaries-obsolete-des/orig/Makefile.orig
2019-12-08 23:05:20.520887001 +
+++ t/tags/checks/binaries/binaries-obsolete-des/orig/Makefile 2019-12-08
23:05:11.092888400 +
@@ -5,7 +5,7 @@
# around, but we have to know the exact "symbol version" associated with
# the obsolete functions, which has to be dug out of libcrypt.so with nm.
-LIBCRYPT_FILE := $(shell dpkg -L libc6-dev | grep 'libcrypt\.so$$')
+LIBCRYPT_FILE := $(shell dpkg -L libcrypt1-dev | grep 'libcrypt\.so$$')
SYMVER := $(shell nm --dynamic --with-symbol-versions $(LIBCRYPT_FILE) | \
grep ' setkey@' | cut -d@ -f2)
Of course you might want to actually query both packages so that lintian
also works for backports.
Regards,
Aurelien
--
Aurelien Jarno GPG: 4096R/1DDD8C9B
aurel...@aurel32.net http://www.aurel32.net
