From patchwork Thu May 14 14:24:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 39247 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 BAB1A396DC27; Thu, 14 May 2020 14:24:41 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org BAB1A396DC27 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1589466281; bh=/2t5nlR9/tE3IsRrIwylMdegdv55GoAyRR3SWiLwTrI=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=quEmtXzQzbI6uVFVgY78qfJ41HUMimiyyE3p2QSn8jZ1+BFpvYykidvZa3ESUFaTK e2TOjPOyGt2upyUGNthHZsxEU7ykvZTsw9kUpLX/QTXgHQLff38vi33fljjmM5aVzV vDuWI1WjSAEEQXm1Yovix7py2/ohe5ZN47OvhqvY= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from us-smtp-delivery-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) by sourceware.org (Postfix) with ESMTP id 644F6396DC1A for ; Thu, 14 May 2020 14:24:38 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 644F6396DC1A 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-389-wG7MlX8sMwCObxnyloh9yg-1; Thu, 14 May 2020 10:24:36 -0400 X-MC-Unique: wG7MlX8sMwCObxnyloh9yg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 54B1380183C for ; Thu, 14 May 2020 14:24:35 +0000 (UTC) Received: from oldenburg2.str.redhat.com (ovpn-113-174.ams2.redhat.com [10.36.113.174]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A1A9C5D9D7 for ; Thu, 14 May 2020 14:24:34 +0000 (UTC) To: libc-alpha@sourceware.org Subject: [PATCH] nss_compat: internal_end*ent may clobber errno, hiding ERANGE [BZ #25976] Date: Thu, 14 May 2020 16:24:33 +0200 Message-ID: <87sgg2wq5a.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 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-14.0 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. --- 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 +++++++++++--- 4 files changed, 46 insertions(+), 11 deletions(-) diff --git a/nss/nss_compat/compat-grp.c b/nss/nss_compat/compat-grp.c index 14aadc6f01..f52d764273 100644 --- a/nss/nss_compat/compat-grp.c +++ b/nss/nss_compat/compat-grp.c @@ -144,7 +144,7 @@ _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) @@ -165,6 +165,15 @@ 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) { @@ -485,7 +494,7 @@ _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; } @@ -614,7 +623,7 @@ _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 67a4c100f6..4032be3308 100644 --- a/nss/nss_compat/compat-initgroups.c +++ b/nss/nss_compat/compat-initgroups.c @@ -134,7 +134,7 @@ 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) @@ -158,6 +158,15 @@ 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, @@ -502,7 +511,7 @@ _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 dfb454f777..69f2ab37db 100644 --- a/nss/nss_compat/compat-pwd.c +++ b/nss/nss_compat/compat-pwd.c @@ -261,7 +261,7 @@ _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) @@ -289,6 +289,15 @@ 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) { @@ -824,7 +833,7 @@ _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; } @@ -1063,7 +1072,7 @@ _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 0a1fde1ea4..908746840d 100644 --- a/nss/nss_compat/compat-spwd.c +++ b/nss/nss_compat/compat-spwd.c @@ -217,7 +217,7 @@ _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) @@ -246,6 +246,15 @@ 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) { @@ -263,7 +272,6 @@ _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, @@ -788,7 +796,7 @@ _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; }