From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 35BFC3858400 for ; Thu, 22 Sep 2022 17:26:11 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 35BFC3858400 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1663867570; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type; bh=ibTPA6jOaPTRhbFI7K82/TyrCGI405GSr28qAfR56Yw=; b=ZXz554VH/vdWgLgO7aYVLa0O8cF7YffXxtLozkQf+K6g+zclZgZ/QxFHH2lLoqrJMHohSe eDV4Kidl1DOhUmFZG8lo7M4r5IUM2vHcWjyFrF4gudLNmJjPVZRxZHG3399YhSlogfkSz0 zYjz3I7mYAyjwj9EbSbYVQ5DsL3c/0I= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-227-1rhNIUdQPV2_aesg6KiGFQ-1; Thu, 22 Sep 2022 13:26:09 -0400 X-MC-Unique: 1rhNIUdQPV2_aesg6KiGFQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6E32983394C for ; Thu, 22 Sep 2022 17:26:09 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.192.103]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EABE2C15BA8 for ; Thu, 22 Sep 2022 17:26:08 +0000 (UTC) From: Florian Weimer To: libc-alpha@sourceware.org Subject: [PATCH] elf: Do not completely clear reused namespace in dlmopen (bug 29600) Date: Thu, 22 Sep 2022 19:26:07 +0200 Message-ID: <87pmfn1ftc.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-11.0 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,KAM_SHORT,RCVD_IN_DNSWL_LOW,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: The data in the _ns_debug member must be preserved, otherwise _dl_debug_initialize enters an infinite loop. To be conservative, only clear the libc_map member for now, to fix bug 29528. Fixes commit d0e357ff45a75553dee3b17ed7d303bfa544f6fe ("elf: Call __libc_early_init for reused namespaces (bug 29528)"), by reverting most of it. Tested on i686-linux-gnu and x86_64-linux-gnu. --- elf/dl-open.c | 14 ++++++-------- elf/tst-dlmopen-twice.c | 28 ++++++++++++++++++++++++---- 2 files changed, 30 insertions(+), 12 deletions(-) diff --git a/elf/dl-open.c b/elf/dl-open.c index 46e8066fd8..e7db5e9642 100644 --- a/elf/dl-open.c +++ b/elf/dl-open.c @@ -844,15 +844,13 @@ _dl_open (const char *file, int mode, const void *caller_dlopen, Lmid_t nsid, _dl_signal_error (EINVAL, file, NULL, N_("\ no more namespaces available for dlmopen()")); } + else if (nsid == GL(dl_nns)) + { + __rtld_lock_initialize (GL(dl_ns)[nsid]._ns_unique_sym_table.lock); + ++GL(dl_nns); + } - if (nsid == GL(dl_nns)) - ++GL(dl_nns); - - /* Initialize the new namespace. Most members are - zero-initialized, only the lock needs special treatment. */ - memset (&GL(dl_ns)[nsid], 0, sizeof (GL(dl_ns)[nsid])); - __rtld_lock_initialize (GL(dl_ns)[nsid]._ns_unique_sym_table.lock); - + GL(dl_ns)[nsid].libc_map = NULL; _dl_debug_update (nsid)->r_state = RT_CONSISTENT; } /* Never allow loading a DSO in a namespace which is empty. Such diff --git a/elf/tst-dlmopen-twice.c b/elf/tst-dlmopen-twice.c index 449f3c8fa9..70c71fe19c 100644 --- a/elf/tst-dlmopen-twice.c +++ b/elf/tst-dlmopen-twice.c @@ -16,18 +16,38 @@ License along with the GNU C Library; if not, see . */ -#include +#include #include +#include -static int -do_test (void) +/* Run the test multiple times, to check finding a new namespace while + another namespace is already in use. This used to trigger bug 29600. */ +static void +recurse (int depth) { - void *handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-twice-mod1.so", RTLD_NOW); + if (depth == 0) + return; + + printf ("info: running at depth %d\n", depth); + void *handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-twice-mod1.so", + RTLD_NOW); xdlclose (handle); handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-twice-mod2.so", RTLD_NOW); int (*run_check) (void) = xdlsym (handle, "run_check"); TEST_COMPARE (run_check (), 0); + recurse (depth - 1); xdlclose (handle); +} + +static int +do_test (void) +{ + /* First run the test without nesting. */ + recurse (1); + + /* Then with nesting. The constant needs to be less than the + internal DL_NNS namespace constant. */ + recurse (10); return 0; } base-commit: 340097d0b50eff9d3058e06c6989ae398c653d4a