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Mon, 07 Sep 2020 15:39:30 +0000 Received: from mout.kundenserver.de ([217.72.192.75]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFJEt-0003tZ-6d for linux-arm-kernel@lists.infradead.org; Mon, 07 Sep 2020 15:39:28 +0000 Received: from threadripper.lan ([149.172.98.151]) by mrelayeu.kundenserver.de (mreue109 [212.227.15.145]) with ESMTPA (Nemesis) id 1N8onQ-1kZk5z39j4-015qTH; Mon, 07 Sep 2020 17:39:17 +0200 From: Arnd Bergmann To: Christoph Hellwig , Russell King , Russell King Subject: [PATCH 6/9] ARM: oabi-compat: rework sys_semtimedop emulation Date: Mon, 7 Sep 2020 17:36:47 +0200 Message-Id: <20200907153701.2981205-7-arnd@arndb.de> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200907153701.2981205-1-arnd@arndb.de> References: <20200907153701.2981205-1-arnd@arndb.de> MIME-Version: 1.0 X-Provags-ID: V03:K1:xJULoYTBL7IEDFaiLfzlEQM1Nn0bBNPGtoKwl3dTiNpPJChDYf7 HjQuRLOi09dJKLXTCL7IlVnsnyVGS2k6JhKIbc+XXnGwHss9qNQ8zzy+B432muK/Wgv9buQ vHVzWggvnayHyVzcZvn1/K140MAMQk1gKEOgEAMSerVtVpXeCivJAf32eCkHicO1Yp/c92Q 4Cg++cukhWIRkx1nLQKDA== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1;V03:K0:IztGozrAq6g=:weTfevA4N3i1Z8UQAnIPZe 6oQ1npzbKSV+BmV0mQeHpDPXavft3VFEubKuPkJi+QHVXeMF/xpj69lhBporemMvX4P3UoTUB XsmhmWIxUVcCIbj2Pv3f7NaeE5BJWzzsLrFnCO6MU1xcc6qipTfJtU9oe5O46gEIc/ZqrjlIE Jgytoiq0kBrkXjzJbJOkb56OPi1at3IVJlQwSjqAZc33SKzS7FzsoKc2CJgMloiphKsTNM9xo xHRuPrFvQ8HfpSK4ci1tcNNUS3kl6Z1RU4uw60MVclFPDPLRhA7dfWTbvUxwqX8fdAIpyqT+3 Ep7CJIC26HG+OwnhBCoF8E3UJBYK0qv34Za4KCaUqAlpDdiP7xWaHqhuarBeznVKcJaKv+VVO S0ea/MsRg1r4FGfsQmicAzFKOTv711UMJzpU7NguY+b1mHBUQiRn17HtCKsU4CYHCESY2uGIh IxLqEWFKF2zkw4rAaJoF8UjWLNuMQ3AOpI+D0MSomChMfbSSXsl6b4DpiOvOsqfeWtq7WV3mp 4x8eVSnsyOIKdS1ScuscfV1fHgYUC6r7sejV+YKeK3FW4sYezAG/EyF2Xkg9TKfw7oW2uzshj ge/ettlqZf0aYQxf0O1DsUs0L938btWyDsgz5MPbFit5DDkicCebtqseMLhkenIAtxurDHxSK DPI4HmCfLTQKwMga70lCy+DsmwgFLVhne1K6i8dk/jCmYSgsFqSBBJt5/96pISCj9Q+9zOUfI /iDlEuK5OWnB1Z/M3/QUKSsyIwsYP5pXQCwNgnPeoY+JYIbKl3G/XQM+EukOq2OkpKgXmvaHz s0zDKBUyfNbH1w1+rzSO0D4Fu7M0Ztvyf10a67YcB+QyYCTvS/N5Aoo1zHM4DRInvIHcEaX X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200907_113927_484678_DD8E4BCA X-CRM114-Status: GOOD ( 29.99 ) X-Spam-Score: 0.0 (/) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (0.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [217.72.192.75 listed in list.dnswl.org] 0.0 SPF_NONE SPF: sender does not publish an SPF Record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 RCVD_IN_MSPIKE_H2 RBL: Average reputation (+2) [217.72.192.75 listed in wl.mailspike.net] 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 Bergmann , linux-api@vger.kernel.org, linus.walleij@linaro.org, kernel@vger.kernel.org, linux-kernel@vger.kernel.org, Dominik Brodowski , Alexander Viro , Christian Brauner , Andrew Morton , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org 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 | 2 + ipc/sem.c | 84 +++++++++++++++++++------------ 3 files changed, 76 insertions(+), 48 deletions(-) diff --git a/arch/arm/kernel/sys_oabi-compat.c b/arch/arm/kernel/sys_oabi-compat.c index abf1153c5315..d3c6460d13ca 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 @@ -293,46 +294,51 @@ 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 75ac7f8ae93c..c77bd4cce536 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -1340,6 +1340,8 @@ 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 8c0244e0365e..515a39a67534 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,