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 [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 8058B3858D39 for ; Mon, 13 Dec 2021 22:07:33 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 8058B3858D39 Received: from mail-io1-f69.google.com (mail-io1-f69.google.com [209.85.166.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-98-S4b991R4O5i_gVKxlssoyw-1; Mon, 13 Dec 2021 17:07:26 -0500 X-MC-Unique: S4b991R4O5i_gVKxlssoyw-1 Received: by mail-io1-f69.google.com with SMTP id o11-20020a0566022e0b00b005e95edf792dso16102173iow.14 for ; Mon, 13 Dec 2021 14:07:26 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:references:from:organization:in-reply-to :content-transfer-encoding; bh=lagbNwNzb5/dN9Fw1JavQ03rdZzhKAxo2A/ocBs05o8=; b=UgATR8oOGoZamUThpFRicMTgGLCj9IY/N/TDaQeMX1r5ovqQb+pV6MxyhB71XeOPgN eBtw4B6ysVODm3WwH5yAgxRWWX7Ao8L8oCirceAiHKLEeixFn8zlZ4WGJAqynaAXW3Oq 1tNPv5hvEu8diESK2CBlyGyhCRjdoLbzWQ4/dnWUAZYv0ccYf9Vk7fd6Wy5nyrKemp6L pByFxs6A/SEyaoijBjR9b6b2jJEbTu5i+oooPfZKyZcwCAHH+N4Y1Y7PCGCxlmxUayYb /WG8eBJQCZbJXMWvOgRCju5tfxEtKfSHxge7QsqgwiAY5rCOCrgjzrHOr1dHaAMfKYlh iLOA== X-Gm-Message-State: AOAM531Qug3RmvzxdajBDqtsv175sAptV6lMedJjKGfV+zTiLrogsvUk cI+W3QbFovqwCaF+zR9wQwyjuv/jFRySjGNo8y9idrQzRxr3STfKUiLlxTskQEyTTjtA1upqpLa 0w4Q8LZU8RrzeW+QcUaBA X-Received: by 2002:a05:6638:140e:: with SMTP id k14mr590277jad.251.1639433245543; Mon, 13 Dec 2021 14:07:25 -0800 (PST) X-Google-Smtp-Source: ABdhPJyPjf/S8489iKTbGn+SXkxWoQgXpYP0xAKdsbzmRkBYXZr/5yGuwpJqC9u+GaIWUBkeuahx8w== X-Received: by 2002:a05:6638:140e:: with SMTP id k14mr590258jad.251.1639433245238; Mon, 13 Dec 2021 14:07:25 -0800 (PST) Received: from [192.168.0.241] (135-23-175-80.cpe.pppoe.ca. [135.23.175.80]) by smtp.gmail.com with ESMTPSA id 8926c6da1cb9f-2faa6b4dadbsm98529173.254.2021.12.13.14.07.23 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 13 Dec 2021 14:07:24 -0800 (PST) Message-ID: <3cf3f178-b974-2968-e7f9-4d8346913652@redhat.com> Date: Mon, 13 Dec 2021 17:07:23 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.3.0 Subject: Re: [PATCH v3 3/3] elf: Also try DT_RUNPATH for LD_AUDIT dlopen [BZ #28455] To: "H.J. Lu" , libc-alpha@sourceware.org References: <20211208152501.1483087-1-hjl.tools@gmail.com> <20211208152501.1483087-4-hjl.tools@gmail.com> From: Carlos O'Donell Organization: Red Hat In-Reply-To: <20211208152501.1483087-4-hjl.tools@gmail.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-14.7 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, NICE_REPLY_A, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 13 Dec 2021 22:07:35 -0000 On 12/8/21 10:25, H.J. Lu wrote: > DT_RUNPATH is only used to find the immediate dependencies of the > executable or shared object containing the DT_RUNPATH entry. Update > the glibc LD_AUDIT dlopen call to try the DT_RUNPATH entry of the > executable. This partially fixes BZ #28455. Please post v4 split out. > --- > elf/Makefile | 9 +++++++-- > elf/dl-load.c | 15 +++++++++++++++ > elf/tst-audit14a.c | 1 + > 3 files changed, 23 insertions(+), 2 deletions(-) > create mode 100644 elf/tst-audit14a.c > > diff --git a/elf/Makefile b/elf/Makefile > index 4b5bdcb08e..aa6b24d790 100644 > --- a/elf/Makefile > +++ b/elf/Makefile > @@ -247,10 +247,10 @@ ifneq ($(selinux-enabled),1) > tests-execstack-yes = tst-execstack tst-execstack-needed tst-execstack-prog > endif > ifeq ($(have-depaudit),yes) > -tests += tst-audit14 tst-audit15 tst-audit16 > +tests += tst-audit14 tst-audit15 tst-audit16 tst-audit14a Please split one test per line and sort. > ifeq ($(run-built-tests),yes) > tests-special += $(objpfx)tst-audit14-cmp.out $(objpfx)tst-audit15-cmp.out \ > - $(objpfx)tst-audit16-cmp.out > + $(objpfx)tst-audit16-cmp.out $(objpfx)tst-audit14a-cmp.out Please split one test per line and sort. > endif > endif > endif > @@ -1521,6 +1521,8 @@ tst-auditmany-ENV = \ > LDFLAGS-tst-audit14 = -Wl,--audit=tst-auditlogmod-1.so > $(objpfx)tst-auditlogmod-1.so: $(libsupport) > $(objpfx)tst-audit14.out: $(objpfx)tst-auditlogmod-1.so > +LDFLAGS-tst-audit14a = -Wl,--audit=tst-auditlogmod-1.so,--enable-new-dtags > +$(objpfx)tst-audit14a.out: $(objpfx)tst-auditlogmod-1.so OK. > LDFLAGS-tst-audit15 = \ > -Wl,--audit=tst-auditlogmod-1.so,--depaudit=tst-auditlogmod-2.so > $(objpfx)tst-auditlogmod-2.so: $(libsupport) > @@ -1547,6 +1549,9 @@ tst-audit17-ENV = LD_AUDIT=$(objpfx)tst-auditmod17.so > $(objpfx)tst-audit14-cmp.out: tst-audit14.exp $(objpfx)tst-audit14.out > cmp $^ > $@; \ > $(evaluate-test) > +$(objpfx)tst-audit14a-cmp.out: tst-audit14.exp $(objpfx)tst-audit14a.out > + cmp $^ > $@; \ > + $(evaluate-test) OK. > $(objpfx)tst-audit15-cmp.out: tst-audit15.exp $(objpfx)tst-audit15.out > cmp $^ > $@; \ > $(evaluate-test) > diff --git a/elf/dl-load.c b/elf/dl-load.c > index bf8957e73c..1f424ea7c8 100644 > --- a/elf/dl-load.c > +++ b/elf/dl-load.c The preceding block is like this: 2146 /* When the object has the RUNPATH information we don't use any 2147 RPATHs. */ 2148 if (loader == NULL || loader->l_info[DT_RUNPATH] == NULL) 2149 { The entire design of this block is to look into DT_RPATH specifically under two conditions: (a) We don't know anything about the loading module, it is NULL, and therefore we don't know if DT_RUNPATH was present, which if it was present, would prevent the use of DT_RPATH. (b) We have a loader, and we know it doesn't have DT_RUNPATH and so we will look for DT_RPATH. Your changes adds (c) to this case in which DT_RUNPATH is used, and this seems to be logically distinct from the above two cases. My suggestion is that the code you are adding should be in a distinct block *after* the above block starting around line 2189. We already have a block like this: 2189 /* Look at the RUNPATH information for this binary. */ 2190 if (fd == -1 && loader != NULL 2191 && cache_rpath (loader, &loader->l_runpath_dirs, 2192 DT_RUNPATH, "RUNPATH")) 2193 fd = open_path (name, namelen, mode, 2194 &loader->l_runpath_dirs, &realname, &fb, loader, 2195 LA_SER_RUNPATH, &found_other_class); I think it is logically more correct to add to this DT_RUNPATH handling than ato add to the DT_RPATH handling above. So after this block you might add: /* When processing the lookup we may need to additionally try DT_RUNPATH in the executable for a glibc internal dlopen call when looking for audit modules. */ if (__glibc_unlikely (mode & __RTLD_AUDIT) && fd == -1) { ... } The hard part is that you may want to know a few things: (a) main_map (unavailable, but computable via GL(dl_ns)[LM_ID_BASE]._ns_loaded) (b) did_main_map (unavailable) * This seems like an optimization because if you already looked up via main_map and it failed, doing it twice won't help, so you can refactor did_main_map to function scope and retain the fact that you did this check already if you want to keep the optimization. Otherwise everything else is there to implement the fix. > @@ -2175,6 +2175,21 @@ _dl_map_object (struct link_map *loader, const char *name, > &main_map->l_rpath_dirs, > &realname, &fb, loader ?: main_map, LA_SER_RUNPATH, > &found_other_class); > + > + /* Also try DT_RUNPATH in the executable for glibc internal > + dlopen call. */ > + if (__glibc_unlikely (mode & __RTLD_AUDIT) > + && fd == -1 && !did_main_map > + && main_map != NULL && main_map->l_type != lt_loaded) > + { > + struct r_search_path_struct l_rpath_dirs; > + l_rpath_dirs.dirs = NULL; > + if (cache_rpath (main_map, &l_rpath_dirs, > + DT_RUNPATH, "RUNPATH")) > + fd = open_path (name, namelen, mode, &l_rpath_dirs, > + &realname, &fb, loader ?: main_map, > + LA_SER_RUNPATH, &found_other_class); > + } > } > > /* Try the LD_LIBRARY_PATH environment variable. */ > diff --git a/elf/tst-audit14a.c b/elf/tst-audit14a.c > new file mode 100644 > index 0000000000..c6232eacf2 > --- /dev/null > +++ b/elf/tst-audit14a.c > @@ -0,0 +1 @@ > +#include "tst-audit14.c" > -- Cheers, Carlos.