From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1944) id 17698385152A; Thu, 27 Oct 2022 13:54:49 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 17698385152A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1666878889; bh=FWLkaqzwF+rKJUu9zb9Wc0KsYM0XIjSYyXLEg1XLY3Y=; h=From:To:Subject:Date:From; b=nX28BYpWXZutANc2faly2Vw38PUINf6EhllF6OVR6GnuU1osckQf7NcmZjiupZrs1 6XPbzopIb7oYx2KKQ6jWF0dLyn1B9YGsqKFhzOKMeFAmA9KPWl6nj76vcOkRyS2o3R 2VG6Kit+BsIAwjfsoWgC3vV0OD8xk6N1y+T93BjU= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Szabolcs Nagy To: glibc-cvs@sourceware.org Subject: [glibc/arm/morello/main] cheri: don't use dl_random for pointer mangling X-Act-Checkin: glibc X-Git-Author: Szabolcs Nagy X-Git-Refname: refs/heads/arm/morello/main X-Git-Oldrev: 1d7fa3f736b795e4e2b953ebc3bd89a8e55471f2 X-Git-Newrev: 8fc31e80652b073dfad49a57f925663db8d618eb Message-Id: <20221027135449.17698385152A@sourceware.org> Date: Thu, 27 Oct 2022 13:54:49 +0000 (GMT) List-Id: https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=8fc31e80652b073dfad49a57f925663db8d618eb commit 8fc31e80652b073dfad49a57f925663db8d618eb Author: Szabolcs Nagy Date: Tue Mar 1 17:36:12 2022 +0000 cheri: don't use dl_random for pointer mangling Pointer mangling cannot be supported on capability architectures. And there is not enough bytes in dl_random for 128 bit pointers. Stack guard is still loaded from dl_random: stack protection is unlikely to be useful on a capability architecture, but it works. Diff: --- sysdeps/unix/sysv/linux/dl-osinfo.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/sysdeps/unix/sysv/linux/dl-osinfo.h b/sysdeps/unix/sysv/linux/dl-osinfo.h index 49d8f973c8..c5d864f5ba 100644 --- a/sysdeps/unix/sysv/linux/dl-osinfo.h +++ b/sysdeps/unix/sysv/linux/dl-osinfo.h @@ -52,7 +52,12 @@ _dl_setup_stack_chk_guard (void *dl_random) static inline uintptr_t __attribute__ ((always_inline)) _dl_setup_pointer_guard (void *dl_random, uintptr_t stack_chk_guard) { +#ifdef __CHERI_PURE_CAPABILITY__ + /* Pointer mangling is not supported on capability architectures. */ + return 0; +#else uintptr_t ret; memcpy (&ret, (char *) dl_random + sizeof (ret), sizeof (ret)); return ret; +#endif }