Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52F0DC433EF for ; Fri, 17 Dec 2021 14:48:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237517AbhLQOsj convert rfc822-to-8bit (ORCPT ); Fri, 17 Dec 2021 09:48:39 -0500 Received: from us-smtp-delivery-44.mimecast.com ([205.139.111.44]:24736 "EHLO us-smtp-delivery-44.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232771AbhLQOsi (ORCPT ); Fri, 17 Dec 2021 09:48:38 -0500 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-288-JQaji_b5MMaSeEWf3zYr9w-1; Fri, 17 Dec 2021 09:48:32 -0500 X-MC-Unique: JQaji_b5MMaSeEWf3zYr9w-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C48468DD87E; Fri, 17 Dec 2021 14:48:29 +0000 (UTC) Received: from comp-core-i7-2640m-0182e6.redhat.com (unknown [10.36.110.2]) by smtp.corp.redhat.com (Postfix) with ESMTP id EAC731037F5B; Fri, 17 Dec 2021 14:48:27 +0000 (UTC) From: Alexey Gladkov To: LKML , Linux Containers Cc: 0day robot , "Eric W . Biederman" , lkp@lists.01.org, kernel test robot Subject: [PATCH v3] ucounts: Split rlimit and ucount values and max values Date: Fri, 17 Dec 2021 15:48:23 +0100 Message-Id: <73ea569042babda5cee2092423da85027ceb471f.1639752364.git.legion@kernel.org> In-Reply-To: <87tufc1p2i.fsf@email.froward.int.ebiederm.org> References: <87tufc1p2i.fsf@email.froward.int.ebiederm.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=legion@kernel.org X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: kernel.org Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset=WINDOWS-1252 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since the semantics of maximum rlimit values are different, it would be better not to mix ucount and rlimit values. This will prevent the error of using inc_count/dec_ucount for rlimit parameters. This patch also renames the functions to emphasize the lack of connection between rlimit and ucount. v2: - Fix the array-index-out-of-bounds that was found by the lkp project. Reported-by: kernel test robot Signed-off-by: Alexey Gladkov --- fs/exec.c | 2 +- fs/proc/array.c | 2 +- include/linux/user_namespace.h | 35 +++++++++++++++++++++------------- kernel/fork.c | 12 ++++++------ kernel/sys.c | 2 +- kernel/ucount.c | 24 ++++++++++------------- kernel/user_namespace.c | 10 +++++----- 7 files changed, 46 insertions(+), 41 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 537d92c41105..d3f769837058 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1877,7 +1877,7 @@ static int do_execveat_common(int fd, struct filename *filename, * whether NPROC limit is still exceeded. */ if ((current->flags & PF_NPROC_EXCEEDED) && - is_ucounts_overlimit(current_ucounts(), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) { + is_rlimit_overlimit(current_ucounts(), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) { retval = -EAGAIN; goto out_ret; } diff --git a/fs/proc/array.c b/fs/proc/array.c index ff869a66b34e..d3fa539c755e 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -274,7 +274,7 @@ static inline void task_sig(struct seq_file *m, struct task_struct *p) collect_sigign_sigcatch(p, &ignored, &caught); num_threads = get_nr_threads(p); rcu_read_lock(); /* FIXME: is this correct? */ - qsize = get_ucounts_value(task_ucounts(p), UCOUNT_RLIMIT_SIGPENDING); + qsize = get_rlimit_value(task_ucounts(p), UCOUNT_RLIMIT_SIGPENDING); rcu_read_unlock(); qlim = task_rlimit(p, RLIMIT_SIGPENDING); unlock_task_sighand(p, &flags); diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index 33a4240e6a6f..45f09bec02c4 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -54,15 +54,17 @@ enum ucount_type { UCOUNT_FANOTIFY_GROUPS, UCOUNT_FANOTIFY_MARKS, #endif + UCOUNT_COUNTS, +}; + +enum rlimit_type { UCOUNT_RLIMIT_NPROC, UCOUNT_RLIMIT_MSGQUEUE, UCOUNT_RLIMIT_SIGPENDING, UCOUNT_RLIMIT_MEMLOCK, - UCOUNT_COUNTS, + UCOUNT_RLIMIT_COUNTS, }; -#define MAX_PER_NAMESPACE_UCOUNTS UCOUNT_RLIMIT_NPROC - struct user_namespace { struct uid_gid_map uid_map; struct uid_gid_map gid_map; @@ -99,6 +101,7 @@ struct user_namespace { #endif struct ucounts *ucounts; long ucount_max[UCOUNT_COUNTS]; + long rlimit_max[UCOUNT_RLIMIT_COUNTS]; } __randomize_layout; struct ucounts { @@ -107,6 +110,7 @@ struct ucounts { kuid_t uid; atomic_t count; atomic_long_t ucount[UCOUNT_COUNTS]; + atomic_long_t rlimit[UCOUNT_RLIMIT_COUNTS]; }; extern struct user_namespace init_user_ns; @@ -120,21 +124,26 @@ struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid); struct ucounts * __must_check get_ucounts(struct ucounts *ucounts); void put_ucounts(struct ucounts *ucounts); -static inline long get_ucounts_value(struct ucounts *ucounts, enum ucount_type type) +static inline long get_rlimit_value(struct ucounts *ucounts, enum rlimit_type type) { - return atomic_long_read(&ucounts->ucount[type]); + return atomic_long_read(&ucounts->rlimit[type]); } -long inc_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v); -bool dec_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v); -long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum ucount_type type); -void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum ucount_type type); -bool is_ucounts_overlimit(struct ucounts *ucounts, enum ucount_type type, unsigned long max); +long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v); +bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v); +long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type); +void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum rlimit_type type); +bool is_rlimit_overlimit(struct ucounts *ucounts, enum rlimit_type type, unsigned long max); + +static inline long get_userns_rlimit_max(struct user_namespace *ns, enum rlimit_type type) +{ + return READ_ONCE(ns->rlimit_max[type]); +} -static inline void set_rlimit_ucount_max(struct user_namespace *ns, - enum ucount_type type, unsigned long max) +static inline void set_userns_rlimit_max(struct user_namespace *ns, + enum rlimit_type type, unsigned long max) { - ns->ucount_max[type] = max <= LONG_MAX ? max : LONG_MAX; + ns->rlimit_max[type] = max <= LONG_MAX ? max : LONG_MAX; } #ifdef CONFIG_USER_NS diff --git a/kernel/fork.c b/kernel/fork.c index 3244cc56b697..fb68d56bcd7e 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -836,13 +836,13 @@ void __init fork_init(void) init_task.signal->rlim[RLIMIT_SIGPENDING] = init_task.signal->rlim[RLIMIT_NPROC]; - for (i = 0; i < MAX_PER_NAMESPACE_UCOUNTS; i++) + for (i = 0; i < UCOUNT_COUNTS; i++) init_user_ns.ucount_max[i] = max_threads/2; - set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_NPROC, RLIM_INFINITY); - set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MSGQUEUE, RLIM_INFINITY); - set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_SIGPENDING, RLIM_INFINITY); - set_rlimit_ucount_max(&init_user_ns, UCOUNT_RLIMIT_MEMLOCK, RLIM_INFINITY); + set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_NPROC, RLIM_INFINITY); + set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_MSGQUEUE, RLIM_INFINITY); + set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_SIGPENDING, RLIM_INFINITY); + set_userns_rlimit_max(&init_user_ns, UCOUNT_RLIMIT_MEMLOCK, RLIM_INFINITY); #ifdef CONFIG_VMAP_STACK cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache", @@ -2053,7 +2053,7 @@ static __latent_entropy struct task_struct *copy_process( DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); #endif retval = -EAGAIN; - if (is_ucounts_overlimit(task_ucounts(p), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) { + if (is_rlimit_overlimit(task_ucounts(p), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) { if (p->real_cred->user != INIT_USER && !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) goto bad_fork_free; diff --git a/kernel/sys.c b/kernel/sys.c index 8fdac0d90504..2c86d245acd6 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -479,7 +479,7 @@ static int set_user(struct cred *new) * for programs doing set*uid()+execve() by harmlessly deferring the * failure to the execve() stage. */ - if (is_ucounts_overlimit(new->ucounts, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC)) && + if (is_rlimit_overlimit(new->ucounts, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC)) && new_user != INIT_USER && !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) current->flags |= PF_NPROC_EXCEEDED; diff --git a/kernel/ucount.c b/kernel/ucount.c index 7b32c356ebc5..22070f004e97 100644 --- a/kernel/ucount.c +++ b/kernel/ucount.c @@ -87,10 +87,6 @@ static struct ctl_table user_table[] = { UCOUNT_ENTRY("max_fanotify_groups"), UCOUNT_ENTRY("max_fanotify_marks"), #endif - { }, - { }, - { }, - { }, { } }; #endif /* CONFIG_SYSCTL */ @@ -261,7 +257,7 @@ void dec_ucount(struct ucounts *ucounts, enum ucount_type type) put_ucounts(ucounts); } -long inc_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v) +long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v) { struct ucounts *iter; long max = LONG_MAX; @@ -273,12 +269,12 @@ long inc_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v) ret = LONG_MAX; else if (iter == ucounts) ret = new; - max = READ_ONCE(iter->ns->ucount_max[type]); + max = get_userns_rlimit_max(iter->ns, type); } return ret; } -bool dec_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v) +bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v) { struct ucounts *iter; long new = -1; /* Silence compiler warning */ @@ -292,7 +288,7 @@ bool dec_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v) } static void do_dec_rlimit_put_ucounts(struct ucounts *ucounts, - struct ucounts *last, enum ucount_type type) + struct ucounts *last, enum rlimit_type type) { struct ucounts *iter, *next; for (iter = ucounts; iter != last; iter = next) { @@ -304,12 +300,12 @@ static void do_dec_rlimit_put_ucounts(struct ucounts *ucounts, } } -void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum ucount_type type) +void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum rlimit_type type) { do_dec_rlimit_put_ucounts(ucounts, NULL, type); } -long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum ucount_type type) +long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type) { /* Caller must hold a reference to ucounts */ struct ucounts *iter; @@ -322,7 +318,7 @@ long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum ucount_type type) goto unwind; if (iter == ucounts) ret = new; - max = READ_ONCE(iter->ns->ucount_max[type]); + max = get_userns_rlimit_max(iter->ns, type); /* * Grab an extra ucount reference for the caller when * the rlimit count was previously 0. @@ -341,16 +337,16 @@ long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum ucount_type type) return 0; } -bool is_ucounts_overlimit(struct ucounts *ucounts, enum ucount_type type, unsigned long rlimit) +bool is_rlimit_overlimit(struct ucounts *ucounts, enum rlimit_type type, unsigned long rlimit) { struct ucounts *iter; long max = rlimit; if (rlimit > LONG_MAX) max = LONG_MAX; for (iter = ucounts; iter; iter = iter->ns->ucounts) { - if (get_ucounts_value(iter, type) > max) + if (get_rlimit_value(iter, type) > max) return true; - max = READ_ONCE(iter->ns->ucount_max[type]); + max = get_userns_rlimit_max(iter->ns, type); } return false; } diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 6b2e3ca7ee99..b9f6729b4e5f 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -119,13 +119,13 @@ int create_user_ns(struct cred *new) ns->owner = owner; ns->group = group; INIT_WORK(&ns->work, free_user_ns); - for (i = 0; i < MAX_PER_NAMESPACE_UCOUNTS; i++) { + for (i = 0; i < UCOUNT_COUNTS; i++) { ns->ucount_max[i] = INT_MAX; } - set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC)); - set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_MSGQUEUE, rlimit(RLIMIT_MSGQUEUE)); - set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_SIGPENDING, rlimit(RLIMIT_SIGPENDING)); - set_rlimit_ucount_max(ns, UCOUNT_RLIMIT_MEMLOCK, rlimit(RLIMIT_MEMLOCK)); + set_userns_rlimit_max(ns, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC)); + set_userns_rlimit_max(ns, UCOUNT_RLIMIT_MSGQUEUE, rlimit(RLIMIT_MSGQUEUE)); + set_userns_rlimit_max(ns, UCOUNT_RLIMIT_SIGPENDING, rlimit(RLIMIT_SIGPENDING)); + set_userns_rlimit_max(ns, UCOUNT_RLIMIT_MEMLOCK, rlimit(RLIMIT_MEMLOCK)); ns->ucounts = ucounts; /* Inherit USERNS_SETGROUPS_ALLOWED from our parent */ -- 2.33.0