From patchwork Wed Feb 15 13:32:39 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: stsp X-Patchwork-Id: 65044 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id C7F1E38582AC for ; Wed, 15 Feb 2023 13:34:58 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org C7F1E38582AC DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1676468098; bh=BkpUl4IjziF+k30QNWuSr+3VSIfaClg+Fa7lsLsF5TU=; h=To:Cc:Subject:Date:In-Reply-To:References:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From:Reply-To:From; b=UTHA7/2k1Js+Aj0/O2qFTpD9DprHbC+r//W+1tHKLwinaFj7P1MJxR+pzYTRny5Sz aVb++W4B/wHzIgPt7YU77Kn8D503/Em/SrAMLRfoiv/9Z9U4nPZOXwlokSlrZCXabk H23q4/bQ8QrwRA8MmKIJIcx9UX8UkTANRkoqBa1Y= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from forward100o.mail.yandex.net (forward100o.mail.yandex.net [IPv6:2a02:6b8:0:1a2d::600]) by sourceware.org (Postfix) with ESMTPS id C0D223858004 for ; Wed, 15 Feb 2023 13:34:36 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org C0D223858004 Received: from forward103q.mail.yandex.net (forward103q.mail.yandex.net [IPv6:2a02:6b8:c0e:50:0:640:b21c:d009]) by forward100o.mail.yandex.net (Yandex) with ESMTP id B54A652ABFD0 for ; Wed, 15 Feb 2023 16:32:48 +0300 (MSK) Received: from vla3-178a3f795968.qloud-c.yandex.net (vla3-178a3f795968.qloud-c.yandex.net [IPv6:2a02:6b8:c15:2584:0:640:178a:3f79]) by forward103q.mail.yandex.net (Yandex) with ESMTP id B165E56A0002 for ; Wed, 15 Feb 2023 16:32:48 +0300 (MSK) Received: by vla3-178a3f795968.qloud-c.yandex.net (smtp/Yandex) with ESMTPSA id jWkZJ01YwCg1-qMosyQkg; Wed, 15 Feb 2023 16:32:47 +0300 X-Yandex-Fwd: 1 To: libc-alpha@sourceware.org Cc: Stas Sergeev Subject: [PATCH 1/2] elf: strdup() l_name if no realname [BZ #30100] Date: Wed, 15 Feb 2023 18:32:39 +0500 Message-Id: <20230215133240.4180776-2-stsp2@yandex.ru> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20230215133240.4180776-1-stsp2@yandex.ru> References: <20230215133240.4180776-1-stsp2@yandex.ru> MIME-Version: 1.0 X-Spam-Status: No, score=-11.5 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_ENVFROM_END_DIGIT, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_LOW, SPF_HELO_NONE, SPF_PASS, 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 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-Patchwork-Original-From: Stas Sergeev via Libc-alpha From: stsp Reply-To: Stas Sergeev Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" _dl_close_worker() has this code: /* This name always is allocated. */ free (imap->l_name); But in that particular case, while indeed being allocated, l_name doesn't point to the start of an allocation: new = (struct link_map *) calloc (sizeof (*new) + audit_space + sizeof (struct link_map *) + sizeof (*newname) + libname_len, 1); ... new->l_symbolic_searchlist.r_list = (struct link_map **) ((char *) (new + 1) + audit_space); new->l_libname = newname = (struct libname_list *) (new->l_symbolic_searchlist.r_list + 1); newname->name = (char *) memcpy (newname + 1, libname, libname_len); ... new->l_name = (char *) newname->name + libname_len - 1; It therefore cannot be freed separately. Use strdup("") as a simple fix. Signed-off-by: Stas Sergeev --- elf/dl-object.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/elf/dl-object.c b/elf/dl-object.c index f1f2ec956c..ab926cd4bf 100644 --- a/elf/dl-object.c +++ b/elf/dl-object.c @@ -122,7 +122,10 @@ _dl_new_object (char *realname, const char *libname, int type, #endif new->l_name = realname; else - new->l_name = (char *) newname->name + libname_len - 1; + /* When realname="", it is not allocated and points to the constant + string. Constness is dropped by an explicit cast. :( + So strdup() it here. */ + new->l_name = __strdup (""); new->l_type = type; /* If we set the bit now since we know it is never used we avoid