From patchwork Fri Oct 30 15:49:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 11870355 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BD136C4741F for ; Fri, 30 Oct 2020 17:04:16 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 31CAB2075E for ; Fri, 30 Oct 2020 17:04:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="pB3yGj44"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="tNj45Aqw" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 31CAB2075E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=FfBc6UNuh1W/C6rS3A9x+/p/jeaek0/VaO+QwOqOrxQ=; b=pB3yGj44w+DLdX2OY4/c5gGIp Jp/AjvYPOi1q8SPxH6oOWddwF0taXqeORIG952C5ny5Hrjxd7Odt+o9jb0poFtg9sCc1ardfKBRO8 PR0eZm3ue2ZY36Xow3aqkfb1CaML6fmjsfYulpBsgHbzOtq1d8CwqFJ8VUOeVknLeNQTDHiodl8En hyD/BHKWzlLxIn8D5RwzfcT1qF+FVAXKriscVIMk2EhSwWh3QqRQFwMDE1YLDZuUNo7CxtWn0I/mY UqFgVJCcZBGnTp+7qEQqSR6+a72PDYsLkEla1CRXnZ39GQUidFIjGrv5D6SdzMQyuM2HiwdRFxgHB IERpIezbQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kYXnx-0001Bg-0J; Fri, 30 Oct 2020 17:03:09 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kYWes-0002xr-H7 for linux-arm-kernel@lists.infradead.org; Fri, 30 Oct 2020 15:49:51 +0000 Received: from localhost.localdomain (HSI-KBW-46-223-126-90.hsi.kabel-badenwuerttemberg.de [46.223.126.90]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B0A3320A8B; Fri, 30 Oct 2020 15:49:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604072981; bh=Nohcs14NXVmzDPgy7u84GYyJC54hRaPFadvgsNBjXrI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tNj45AqwPZGaVSNZpP/1A40HzTQLDVBwf2c34+4NvqbGTUhoh/FO1BRqJrOzNVruE LD4BOIie9hoNn4iQjlQcwnREWhJReYlSVouLAnKm8M47AUNXUKe7p+0J5aXJlKS3Jx fB308cFDSQauT/MWaRTsr+6FJpvDCoAqru2H5sJE= From: Arnd Bergmann To: Russell King , Christoph Hellwig Subject: [PATCH 6/9] ARM: oabi-compat: rework sys_semtimedop emulation Date: Fri, 30 Oct 2020 16:49:16 +0100 Message-Id: <20201030154919.1246645-6-arnd@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20201030154919.1246645-1-arnd@kernel.org> References: <20201030154519.1245983-1-arnd@kernel.org> <20201030154919.1246645-1-arnd@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201030_114942_900899_F0AF6662 X-CRM114-Status: GOOD ( 30.00 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, arnd@arndb.de, linus.walleij@linaro.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, viro@zeniv.linux.org.uk, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Arnd Bergmann sys_oabi_semtimedop() is one of the last users of set_fs() on Arm. To remove this one, expose the internal code of the actual implementation that operates on a kernel pointer and call it directly after copying. There should be no measurable impact on the normal execution of this function, and it makes the overly long function a little shorter, which may help readability. While reworking the oabi version, make it behave a little more like the native one, using kvmalloc_array() and restructure the code flow in a similar way. The naming of __do_semtimedop() is not very good, I hope someone can come up with a better name. One regression was spotted by kernel test robot and fixed before the first mailing list submission. Signed-off-by: Arnd Bergmann --- arch/arm/kernel/sys_oabi-compat.c | 38 ++++++++------ include/linux/syscalls.h | 3 ++ ipc/sem.c | 84 +++++++++++++++++++------------ 3 files changed, 77 insertions(+), 48 deletions(-) diff --git a/arch/arm/kernel/sys_oabi-compat.c b/arch/arm/kernel/sys_oabi-compat.c index f9d8e5be6ba0..c3e63b73b6ae 100644 --- a/arch/arm/kernel/sys_oabi-compat.c +++ b/arch/arm/kernel/sys_oabi-compat.c @@ -80,6 +80,7 @@ #include #include #include +#include #include #include @@ -294,46 +295,51 @@ struct oabi_sembuf { unsigned short __pad; }; +#define sc_semopm sem_ctls[2] + asmlinkage long sys_oabi_semtimedop(int semid, struct oabi_sembuf __user *tsops, unsigned nsops, const struct old_timespec32 __user *timeout) { + struct ipc_namespace *ns; struct sembuf *sops; - struct old_timespec32 local_timeout; long err; int i; + ns = current->nsproxy->ipc_ns; + if (nsops > ns->sc_semopm) + return -E2BIG; if (nsops < 1 || nsops > SEMOPM) return -EINVAL; - if (!access_ok(tsops, sizeof(*tsops) * nsops)) - return -EFAULT; - sops = kmalloc_array(nsops, sizeof(*sops), GFP_KERNEL); + sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL); if (!sops) return -ENOMEM; err = 0; for (i = 0; i < nsops; i++) { struct oabi_sembuf osb; - err |= __copy_from_user(&osb, tsops, sizeof(osb)); + err |= copy_from_user(&osb, tsops, sizeof(osb)); sops[i].sem_num = osb.sem_num; sops[i].sem_op = osb.sem_op; sops[i].sem_flg = osb.sem_flg; tsops++; } - if (timeout) { - /* copy this as well before changing domain protection */ - err |= copy_from_user(&local_timeout, timeout, sizeof(*timeout)); - timeout = &local_timeout; - } if (err) { err = -EFAULT; - } else { - mm_segment_t fs = get_fs(); - set_fs(KERNEL_DS); - err = sys_semtimedop_time32(semid, sops, nsops, timeout); - set_fs(fs); + goto out; + } + + if (timeout) { + struct timespec64 ts; + err = get_old_timespec32(&ts, timeout); + if (err) + goto out; + err = __do_semtimedop(semid, sops, nsops, &ts, ns); + goto out; } - kfree(sops); + err = __do_semtimedop(semid, sops, nsops, NULL, ns); +out: + kvfree(sops); return err; } diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 37bea07c12f2..fc7340fa4702 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -1342,6 +1342,9 @@ long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf); long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems, unsigned int nsops, const struct old_timespec32 __user *timeout); +long __do_semtimedop(int semid, struct sembuf *tsems, unsigned int nsops, + const struct timespec64 *timeout, + struct ipc_namespace *ns); int __sys_getsockopt(int fd, int level, int optname, char __user *optval, int __user *optlen); diff --git a/ipc/sem.c b/ipc/sem.c index f6c30a85dadf..c7725031c2ba 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -1978,46 +1978,34 @@ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid) return un; } -static long do_semtimedop(int semid, struct sembuf __user *tsops, - unsigned nsops, const struct timespec64 *timeout) +long __do_semtimedop(int semid, struct sembuf *sops, + unsigned nsops, const struct timespec64 *timeout, + struct ipc_namespace *ns) { int error = -EINVAL; struct sem_array *sma; - struct sembuf fast_sops[SEMOPM_FAST]; - struct sembuf *sops = fast_sops, *sop; + struct sembuf *sop; struct sem_undo *un; int max, locknum; bool undos = false, alter = false, dupsop = false; struct sem_queue queue; unsigned long dup = 0, jiffies_left = 0; - struct ipc_namespace *ns; - - ns = current->nsproxy->ipc_ns; if (nsops < 1 || semid < 0) return -EINVAL; if (nsops > ns->sc_semopm) return -E2BIG; - if (nsops > SEMOPM_FAST) { - sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL); - if (sops == NULL) - return -ENOMEM; - } - - if (copy_from_user(sops, tsops, nsops * sizeof(*tsops))) { - error = -EFAULT; - goto out_free; - } if (timeout) { if (timeout->tv_sec < 0 || timeout->tv_nsec < 0 || timeout->tv_nsec >= 1000000000L) { error = -EINVAL; - goto out_free; + goto out; } jiffies_left = timespec64_to_jiffies(timeout); } + max = 0; for (sop = sops; sop < sops + nsops; sop++) { unsigned long mask = 1ULL << ((sop->sem_num) % BITS_PER_LONG); @@ -2046,7 +2034,7 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops, un = find_alloc_undo(ns, semid); if (IS_ERR(un)) { error = PTR_ERR(un); - goto out_free; + goto out; } } else { un = NULL; @@ -2057,25 +2045,25 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops, if (IS_ERR(sma)) { rcu_read_unlock(); error = PTR_ERR(sma); - goto out_free; + goto out; } error = -EFBIG; if (max >= sma->sem_nsems) { rcu_read_unlock(); - goto out_free; + goto out; } error = -EACCES; if (ipcperms(ns, &sma->sem_perm, alter ? S_IWUGO : S_IRUGO)) { rcu_read_unlock(); - goto out_free; + goto out; } error = security_sem_semop(&sma->sem_perm, sops, nsops, alter); if (error) { rcu_read_unlock(); - goto out_free; + goto out; } error = -EIDRM; @@ -2089,7 +2077,7 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops, * entangled here and why it's RMID race safe on comments at sem_lock() */ if (!ipc_valid_object(&sma->sem_perm)) - goto out_unlock_free; + goto out_unlock; /* * semid identifiers are not unique - find_alloc_undo may have * allocated an undo structure, it was invalidated by an RMID @@ -2098,7 +2086,7 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops, * "un" itself is guaranteed by rcu. */ if (un && un->semid == -1) - goto out_unlock_free; + goto out_unlock; queue.sops = sops; queue.nsops = nsops; @@ -2124,10 +2112,10 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops, rcu_read_unlock(); wake_up_q(&wake_q); - goto out_free; + goto out; } if (error < 0) /* non-blocking error path */ - goto out_unlock_free; + goto out_unlock; /* * We need to sleep on this operation, so we put the current @@ -2192,14 +2180,14 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops, if (error != -EINTR) { /* see SEM_BARRIER_2 for purpose/pairing */ smp_acquire__after_ctrl_dep(); - goto out_free; + goto out; } rcu_read_lock(); locknum = sem_lock(sma, sops, nsops); if (!ipc_valid_object(&sma->sem_perm)) - goto out_unlock_free; + goto out_unlock; /* * No necessity for any barrier: We are protect by sem_lock() @@ -2211,7 +2199,7 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops, * Leave without unlink_queue(), but with sem_unlock(). */ if (error != -EINTR) - goto out_unlock_free; + goto out_unlock; /* * If an interrupt occurred we have to clean up the queue. @@ -2222,13 +2210,45 @@ static long do_semtimedop(int semid, struct sembuf __user *tsops, unlink_queue(sma, &queue); -out_unlock_free: +out_unlock: sem_unlock(sma, locknum); rcu_read_unlock(); +out: + return error; +} + +static long do_semtimedop(int semid, struct sembuf __user *tsops, + unsigned nsops, const struct timespec64 *timeout) +{ + struct sembuf fast_sops[SEMOPM_FAST]; + struct sembuf *sops = fast_sops; + struct ipc_namespace *ns; + int ret; + + ns = current->nsproxy->ipc_ns; + if (nsops > ns->sc_semopm) + return -E2BIG; + if (nsops < 1) + return -EINVAL; + + if (nsops > SEMOPM_FAST) { + sops = kvmalloc_array(nsops, sizeof(*sops), GFP_KERNEL); + if (sops == NULL) + return -ENOMEM; + } + + if (copy_from_user(sops, tsops, nsops * sizeof(*tsops))) { + ret = -EFAULT; + goto out_free; + } + + ret = __do_semtimedop(semid, sops, nsops, timeout, ns); + out_free: if (sops != fast_sops) kvfree(sops); - return error; + + return ret; } long ksys_semtimedop(int semid, struct sembuf __user *tsops,