From patchwork Tue May 19 14:55:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 39321 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 A0639393BC2C; Tue, 19 May 2020 14:55:43 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org A0639393BC2C DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1589900143; bh=FGdUCP6oSxO87wMp/QzOLcSl2InRjc2f8puQ4loIyDA=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=vkO9nYEdjWppCWYz3Cag16uO3yGJ+ywfirRYuz74OgoTMBBP6Tf65ARvTVMfm/Qil ERSLH9TS6m2QZZ5a1MsRU1nXRNJyN6N//S53M6Ccy+2epjr2OS63q6aF7L7X0UQosz QVfQVIUR/QPSCzMB+/CNDskzhOMiNAMHj0WOxJgg= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from us-smtp-1.mimecast.com (us-smtp-2.mimecast.com [205.139.110.61]) by sourceware.org (Postfix) with ESMTP id 4D7243938C10 for ; Tue, 19 May 2020 14:55:41 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 4D7243938C10 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-402-nkcb0IWKPrqexQAV_LypvA-1; Tue, 19 May 2020 10:55:39 -0400 X-MC-Unique: nkcb0IWKPrqexQAV_LypvA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 58A17800D24 for ; Tue, 19 May 2020 14:55:38 +0000 (UTC) Received: from oldenburg2.str.redhat.com (ovpn-113-18.ams2.redhat.com [10.36.113.18]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A2FFD6E71C for ; Tue, 19 May 2020 14:55:37 +0000 (UTC) To: libc-alpha@sourceware.org Subject: [2.31 COMMITTED] nss_compat: internal_end*ent may clobber errno, hiding ERANGE [BZ #25976] Date: Tue, 19 May 2020 16:55:36 +0200 Message-ID: <87pnb0ezyv.fsf@oldenburg2.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-14.1 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) 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: Florian Weimer via Libc-alpha From: Florian Weimer Reply-To: Florian Weimer Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" During cleanup, before returning from get*_r functions, the end*ent calls must not change errno. Otherwise, an ERANGE error from the underlying implementation can be hidden, causing unexpected lookup failures. This commit introduces an internal_end*ent_noerror function which saves and restore errno, and marks the original internal_end*ent function as warn_unused_result, so that it is used only in contexts were errors from it can be handled explicitly. Reviewed-by: DJ Delorie (cherry picked from commit 790b8dda4455865cb8c3a47801f4304c1a43baf6) --- NEWS | 1 + nss/nss_compat/compat-grp.c | 15 ++++++++++++--- nss/nss_compat/compat-initgroups.c | 13 +++++++++++-- nss/nss_compat/compat-pwd.c | 15 ++++++++++++--- nss/nss_compat/compat-spwd.c | 14 +++++++++++--- 5 files changed, 47 insertions(+), 11 deletions(-) diff --git a/NEWS b/NEWS index 9bfd01ccb1..24371e5745 100644 --- a/NEWS +++ b/NEWS @@ -22,6 +22,7 @@ The following bugs are resolved with this release: [25896] Incorrect prctl [25902] Bad LOADARGS_N [25966] Incorrect access of __x86_shared_non_temporal_threshold for x32 + [25976] nss_compat: internal_end*ent may clobber errno, hiding ERANGE Security related changes: diff --git a/nss/nss_compat/compat-grp.c b/nss/nss_compat/compat-grp.c index a8de1e03b3..f8b19a5cf0 100644 --- a/nss/nss_compat/compat-grp.c +++ b/nss/nss_compat/compat-grp.c @@ -142,7 +142,7 @@ _nss_compat_setgrent (int stayopen) } -static enum nss_status +static enum nss_status __attribute_warn_unused_result__ internal_endgrent (ent_t *ent) { if (ent->stream != NULL) @@ -163,6 +163,15 @@ internal_endgrent (ent_t *ent) return NSS_STATUS_SUCCESS; } +/* Like internal_endgrent, but preserve errno in all cases. */ +static void +internal_endgrent_noerror (ent_t *ent) +{ + int saved_errno = errno; + enum nss_status unused __attribute__ ((unused)) = internal_endgrent (ent); + __set_errno (saved_errno); +} + enum nss_status _nss_compat_endgrent (void) { @@ -483,7 +492,7 @@ _nss_compat_getgrnam_r (const char *name, struct group *grp, if (result == NSS_STATUS_SUCCESS) result = internal_getgrnam_r (name, grp, &ent, buffer, buflen, errnop); - internal_endgrent (&ent); + internal_endgrent_noerror (&ent); return result; } @@ -612,7 +621,7 @@ _nss_compat_getgrgid_r (gid_t gid, struct group *grp, if (result == NSS_STATUS_SUCCESS) result = internal_getgrgid_r (gid, grp, &ent, buffer, buflen, errnop); - internal_endgrent (&ent); + internal_endgrent_noerror (&ent); return result; } diff --git a/nss/nss_compat/compat-initgroups.c b/nss/nss_compat/compat-initgroups.c index 939b25b33b..7591442ff9 100644 --- a/nss/nss_compat/compat-initgroups.c +++ b/nss/nss_compat/compat-initgroups.c @@ -133,7 +133,7 @@ internal_setgrent (ent_t *ent) } -static enum nss_status +static enum nss_status __attribute_warn_unused_result__ internal_endgrent (ent_t *ent) { if (ent->stream != NULL) @@ -157,6 +157,15 @@ internal_endgrent (ent_t *ent) return NSS_STATUS_SUCCESS; } +/* Like internal_endgrent, but preserve errno in all cases. */ +static void +internal_endgrent_noerror (ent_t *ent) +{ + int saved_errno = errno; + enum nss_status unused __attribute__ ((unused)) = internal_endgrent (ent); + __set_errno (saved_errno); +} + /* Add new group record. */ static void add_group (long int *start, long int *size, gid_t **groupsp, long int limit, @@ -501,7 +510,7 @@ _nss_compat_initgroups_dyn (const char *user, gid_t group, long int *start, done: scratch_buffer_free (&tmpbuf); - internal_endgrent (&intern); + internal_endgrent_noerror (&intern); return status; } diff --git a/nss/nss_compat/compat-pwd.c b/nss/nss_compat/compat-pwd.c index ec3f35c594..bd5e707da0 100644 --- a/nss/nss_compat/compat-pwd.c +++ b/nss/nss_compat/compat-pwd.c @@ -259,7 +259,7 @@ _nss_compat_setpwent (int stayopen) } -static enum nss_status +static enum nss_status __attribute_warn_unused_result__ internal_endpwent (ent_t *ent) { if (ent->stream != NULL) @@ -287,6 +287,15 @@ internal_endpwent (ent_t *ent) return NSS_STATUS_SUCCESS; } +/* Like internal_endpwent, but preserve errno in all cases. */ +static void +internal_endpwent_noerror (ent_t *ent) +{ + int saved_errno = errno; + enum nss_status unused __attribute__ ((unused)) = internal_endpwent (ent); + __set_errno (saved_errno); +} + enum nss_status _nss_compat_endpwent (void) { @@ -822,7 +831,7 @@ _nss_compat_getpwnam_r (const char *name, struct passwd *pwd, if (result == NSS_STATUS_SUCCESS) result = internal_getpwnam_r (name, pwd, &ent, buffer, buflen, errnop); - internal_endpwent (&ent); + internal_endpwent_noerror (&ent); return result; } @@ -1061,7 +1070,7 @@ _nss_compat_getpwuid_r (uid_t uid, struct passwd *pwd, if (result == NSS_STATUS_SUCCESS) result = internal_getpwuid_r (uid, pwd, &ent, buffer, buflen, errnop); - internal_endpwent (&ent); + internal_endpwent_noerror (&ent); return result; } diff --git a/nss/nss_compat/compat-spwd.c b/nss/nss_compat/compat-spwd.c index f6b7a1ef15..d0e3c51b45 100644 --- a/nss/nss_compat/compat-spwd.c +++ b/nss/nss_compat/compat-spwd.c @@ -215,7 +215,7 @@ _nss_compat_setspent (int stayopen) } -static enum nss_status +static enum nss_status __attribute_warn_unused_result__ internal_endspent (ent_t *ent) { if (ent->stream != NULL) @@ -244,6 +244,15 @@ internal_endspent (ent_t *ent) return NSS_STATUS_SUCCESS; } +/* Like internal_endspent, but preserve errno in all cases. */ +static void +internal_endspent_noerror (ent_t *ent) +{ + int saved_errno = errno; + enum nss_status unused __attribute__ ((unused)) = internal_endspent (ent); + __set_errno (saved_errno); +} + enum nss_status _nss_compat_endspent (void) { @@ -261,7 +270,6 @@ _nss_compat_endspent (void) return result; } - static enum nss_status getspent_next_nss_netgr (const char *name, struct spwd *result, ent_t *ent, char *group, char *buffer, size_t buflen, @@ -786,7 +794,7 @@ _nss_compat_getspnam_r (const char *name, struct spwd *pwd, if (result == NSS_STATUS_SUCCESS) result = internal_getspnam_r (name, pwd, &ent, buffer, buflen, errnop); - internal_endspent (&ent); + internal_endspent_noerror (&ent); return result; }