svn commit: r265003 - head/secure/usr.sbin/sshd
Roger Pau Monné
royger at FreeBSD.org
Wed Aug 20 14:41:16 UTC 2014
On 27/04/14 07:28, Konstantin Belousov wrote:
> Author: kib
> Date: Sun Apr 27 05:28:14 2014
> New Revision: 265003
> URL: http://svnweb.freebsd.org/changeset/base/265003
>
> Log:
> Fix order of libthr and libc in the global dso list for sshd, by
> explicitely linking main binary with -lpthread. Before, libthr
> appeared in the list due to dependency of one of the kerberos libs.
> Due to the change in ld(1) behaviour of not copying NEEDED entries
> from direct dependencies into the link results, the order becomes
> reversed.
>
> The libthr must appear before libc to properly interpose libc symbols
> and provide working rtld locks implementation. The symptom was sshd
> hanging on rtld bind lock during nested symbol binding from a signal
> handler.
>
> Approved by: des (openssh maintainer)
> Sponsored by: The FreeBSD Foundation
> MFC after: 1 week
>
> Modified:
> head/secure/usr.sbin/sshd/Makefile
>
> Modified: head/secure/usr.sbin/sshd/Makefile
> ==============================================================================
> --- head/secure/usr.sbin/sshd/Makefile Sun Apr 27 05:19:01 2014 (r265002)
> +++ head/secure/usr.sbin/sshd/Makefile Sun Apr 27 05:28:14 2014 (r265003)
> @@ -57,6 +57,16 @@ CFLAGS+= -DNONE_CIPHER_ENABLED
> DPADD+= ${LIBCRYPT} ${LIBCRYPTO} ${LIBZ}
> LDADD+= -lcrypt -lcrypto -lz
>
> +# Fix the order of NEEDED entries for libthr and libc. The libthr
> +# needs to interpose libc symbols, leaving the libthr loading as
> +# dependency of krb causes reversed order and broken interposing. Put
> +# the threading library last on the linker command line, just before
> +# the -lc added by a compiler driver.
> +.if ${MK_KERBEROS_SUPPORT} != "no"
> +DPADD+= ${LIBPTHREAD}
> +LDADD+= -lpthread
> +.endif
> +
> .if defined(LOCALBASE)
> CFLAGS+= -DXAUTH_PATH=\"${LOCALBASE}/bin/xauth\"
> .endif
Hello,
This change makes the following simple test program fail on the second
assert. The problem is that sa_handler == SIG_DFL, and sa_flags ==
SA_SIGINFO, which according to the sigaction(9) man page is not
possible. With this change reverted the test is successful.
---
#include <signal.h>
#include <string.h>
#include <assert.h>
int main(int argn, char **argv)
{
struct sigaction new, old;
int rc;
memset(&new, 0, sizeof(new));
memset(&old, 0, sizeof(old));
sigemptyset(&new.sa_mask);
new.sa_handler = SIG_DFL;
new.sa_flags = 0;
rc = sigaction(SIGCHLD, &new, &old);
assert(rc == 0);
assert((old.sa_handler == SIG_DFL || old.sa_handler == SIG_IGN) &&
!(old.sa_flags & SA_SIGINFO));
return (0);
}
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