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Mon, 14 Feb 2022 16:47:38 +0000 Received: from sin.source.kernel.org ([2604:1380:40e1:4800::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nJeMl-00G3tf-KW; Mon, 14 Feb 2022 16:38:25 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id D7930CE19D3; Mon, 14 Feb 2022 16:38:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8C689C340F1; Mon, 14 Feb 2022 16:38:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1644856695; bh=/kKTMMBRz92UJDg2siwhTka/klTYwXBQSyhpE5zcpAY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=d6iGqrb4uihekO2J29RlsPjWSIirVefXmDJ88V61I2FZj8NHe6/A5hTSRNv9H4enQ GpEYgqwBL+KNTdSHBGmNqO5Ca3Fck3bhH14uS6wLfT37UBHyRfDvT3yFSib1sCW5QF eAhsrZrSBQaMDCsEYQwWOsmyUtEDJVqdFCPBuFmnfxL6+e3v/Wn3BwgEgEMaWUfUtg mthZufLStsec1t9lai6wgSu0ifX/lj9v+LQIBhG3i5SHSvKmR7YS38hzd+JLAMvu4B 9ri3nXMl8RNML8xS+WpAQYY7OrdC+8aYdXd2ODrskXQV1GSIenfVH9itu0Tl79sAMa qWh7rcKCE0QFA== From: Arnd Bergmann To: Linus Torvalds , Christoph Hellwig , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org, arnd@arndb.de, linux-kernel@vger.kernel.org Cc: linux@armlinux.org.uk, will@kernel.org, guoren@kernel.org, bcain@codeaurora.org, geert@linux-m68k.org, monstr@monstr.eu, tsbogend@alpha.franken.de, nickhu@andestech.com, green.hu@gmail.com, dinguyen@kernel.org, shorne@gmail.com, deller@gmx.de, mpe@ellerman.id.au, peterz@infradead.org, mingo@redhat.com, mark.rutland@arm.com, hca@linux.ibm.com, dalias@libc.org, davem@davemloft.net, richard@nod.at, x86@kernel.org, jcmvbkbc@gmail.com, ebiederm@xmission.com, akpm@linux-foundation.org, ardb@kernel.org, linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org Subject: [PATCH 14/14] uaccess: drop set_fs leftovers Date: Mon, 14 Feb 2022 17:34:52 +0100 Message-Id: <20220214163452.1568807-15-arnd@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20220214163452.1568807-1-arnd@kernel.org> References: <20220214163452.1568807-1-arnd@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220214_083820_127703_41295742 X-CRM114-Status: GOOD ( 26.79 ) X-Spam-Score: -5.4 (-----) X-Spam-Report: Spam detection software, running on the system "bombadil.infradead.org", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: From: Arnd Bergmann There are no more users of CONFIG_SET_FS left, so drop all remaining references to set_fs()/get_fs(), mm_segment_t and uaccess_kernel(). Signed-off-by: Arnd Bergmann --- arch/Kconfig | 3 --- arch/arm/lib/uaccess_with_memcpy.c | 10 --------- arch/nds32/kernel/process.c | 5 ++--- arch/parisc/include/asm/futex.h | 2 +- arc [...] Content analysis details: (-5.4 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [2604:1380:40e1:4800:0:0:0:1 listed in] [list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.2 DKIMWL_WL_HIGH DKIMwl.org - High trust sender X-BeenThere: linux-snps-arc@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux on Synopsys ARC Processors List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org From: Arnd Bergmann There are no more users of CONFIG_SET_FS left, so drop all remaining references to set_fs()/get_fs(), mm_segment_t and uaccess_kernel(). Signed-off-by: Arnd Bergmann --- arch/Kconfig | 3 --- arch/arm/lib/uaccess_with_memcpy.c | 10 --------- arch/nds32/kernel/process.c | 5 ++--- arch/parisc/include/asm/futex.h | 2 +- arch/parisc/lib/memcpy.c | 2 +- drivers/hid/uhid.c | 2 +- drivers/scsi/sg.c | 5 ----- fs/exec.c | 6 ------ include/asm-generic/access_ok.h | 10 +-------- include/linux/syscalls.h | 4 ---- include/linux/uaccess.h | 33 ------------------------------ include/rdma/ib.h | 2 +- kernel/events/callchain.c | 4 ---- kernel/events/core.c | 3 --- kernel/exit.c | 14 ------------- kernel/kthread.c | 5 ----- kernel/stacktrace.c | 3 --- kernel/trace/bpf_trace.c | 4 ---- mm/maccess.c | 11 ---------- mm/memory.c | 8 -------- net/bpfilter/bpfilter_kern.c | 2 +- 21 files changed, 8 insertions(+), 130 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index 678a80713b21..96075a12c720 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -24,9 +24,6 @@ config KEXEC_ELF config HAVE_IMA_KEXEC bool -config SET_FS - bool - config HOTPLUG_SMT bool diff --git a/arch/arm/lib/uaccess_with_memcpy.c b/arch/arm/lib/uaccess_with_memcpy.c index 106f83a5ea6d..c30b689bec2e 100644 --- a/arch/arm/lib/uaccess_with_memcpy.c +++ b/arch/arm/lib/uaccess_with_memcpy.c @@ -92,11 +92,6 @@ __copy_to_user_memcpy(void __user *to, const void *from, unsigned long n) unsigned long ua_flags; int atomic; - if (uaccess_kernel()) { - memcpy((void *)to, from, n); - return 0; - } - /* the mmap semaphore is taken only if not in an atomic context */ atomic = faulthandler_disabled(); @@ -165,11 +160,6 @@ __clear_user_memset(void __user *addr, unsigned long n) { unsigned long ua_flags; - if (uaccess_kernel()) { - memset((void *)addr, 0, n); - return 0; - } - mmap_read_lock(current->mm); while (n) { pte_t *pte; diff --git a/arch/nds32/kernel/process.c b/arch/nds32/kernel/process.c index 49fab9e39cbf..d35c1f63fa11 100644 --- a/arch/nds32/kernel/process.c +++ b/arch/nds32/kernel/process.c @@ -119,9 +119,8 @@ void show_regs(struct pt_regs *regs) regs->uregs[7], regs->uregs[6], regs->uregs[5], regs->uregs[4]); pr_info("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n", regs->uregs[3], regs->uregs[2], regs->uregs[1], regs->uregs[0]); - pr_info(" IRQs o%s Segment %s\n", - interrupts_enabled(regs) ? "n" : "ff", - uaccess_kernel() ? "kernel" : "user"); + pr_info(" IRQs o%s Segment user\n", + interrupts_enabled(regs) ? "n" : "ff"); } EXPORT_SYMBOL(show_regs); diff --git a/arch/parisc/include/asm/futex.h b/arch/parisc/include/asm/futex.h index b5835325d44b..2f4a1b1ef387 100644 --- a/arch/parisc/include/asm/futex.h +++ b/arch/parisc/include/asm/futex.h @@ -99,7 +99,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, /* futex.c wants to do a cmpxchg_inatomic on kernel NULL, which is * our gateway page, and causes no end of trouble... */ - if (uaccess_kernel() && !uaddr) + if (!uaddr) return -EFAULT; if (!access_ok(uaddr, sizeof(u32))) diff --git a/arch/parisc/lib/memcpy.c b/arch/parisc/lib/memcpy.c index ea70a0e08321..468704ce8a1c 100644 --- a/arch/parisc/lib/memcpy.c +++ b/arch/parisc/lib/memcpy.c @@ -13,7 +13,7 @@ #include #include -#define get_user_space() (uaccess_kernel() ? 0 : mfsp(3)) +#define get_user_space() (mfsp(3)) #define get_kernel_space() (0) /* Returns 0 for success, otherwise, returns number of bytes not transferred. */ diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index 614adb510dbd..2a918aeb0af1 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -747,7 +747,7 @@ static ssize_t uhid_char_write(struct file *file, const char __user *buffer, * copied from, so it's unsafe to allow this with elevated * privileges (e.g. from a setuid binary) or via kernel_write(). */ - if (file->f_cred != current_cred() || uaccess_kernel()) { + if (file->f_cred != current_cred()) { pr_err_once("UHID_CREATE from different security context by process %d (%s), this is not allowed.\n", task_tgid_vnr(current), current->comm); ret = -EACCES; diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 6b43e97bd417..aaa2376b9d34 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -224,11 +224,6 @@ static int sg_check_file_access(struct file *filp, const char *caller) caller, task_tgid_vnr(current), current->comm); return -EPERM; } - if (uaccess_kernel()) { - pr_err_once("%s: process %d (%s) called from kernel context, this is not allowed.\n", - caller, task_tgid_vnr(current), current->comm); - return -EACCES; - } return 0; } diff --git a/fs/exec.c b/fs/exec.c index 79f2c9483302..bc68a0c089ac 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1303,12 +1303,6 @@ int begin_new_exec(struct linux_binprm * bprm) if (retval) goto out_unlock; - /* - * Ensure that the uaccess routines can actually operate on userspace - * pointers: - */ - force_uaccess_begin(); - if (me->flags & PF_KTHREAD) free_kthread_struct(me); me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | diff --git a/include/asm-generic/access_ok.h b/include/asm-generic/access_ok.h index 883b573af5fe..725647ba8ea9 100644 --- a/include/asm-generic/access_ok.h +++ b/include/asm-generic/access_ok.h @@ -16,16 +16,8 @@ #define TASK_SIZE_MAX TASK_SIZE #endif -#ifndef uaccess_kernel -#ifdef CONFIG_SET_FS -#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) -#else -#define uaccess_kernel() (0) -#endif -#endif - #ifndef user_addr_max -#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE_MAX) +#define user_addr_max() TASK_SIZE_MAX #endif #ifndef __access_ok diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 819c0cb00b6d..a34b0f9a9972 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -290,10 +290,6 @@ static inline void addr_limit_user_check(void) return; #endif - if (CHECK_DATA_CORRUPTION(uaccess_kernel(), - "Invalid address limit on user-mode return")) - force_sig(SIGKILL); - #ifdef TIF_FSCHECK clear_thread_flag(TIF_FSCHECK); #endif diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index 2c31667e62e0..2421a41f3a8e 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -10,39 +10,6 @@ #include -#ifdef CONFIG_SET_FS -/* - * Force the uaccess routines to be wired up for actual userspace access, - * overriding any possible set_fs(KERNEL_DS) still lingering around. Undone - * using force_uaccess_end below. - */ -static inline mm_segment_t force_uaccess_begin(void) -{ - mm_segment_t fs = get_fs(); - - set_fs(USER_DS); - return fs; -} - -static inline void force_uaccess_end(mm_segment_t oldfs) -{ - set_fs(oldfs); -} -#else /* CONFIG_SET_FS */ -typedef struct { - /* empty dummy */ -} mm_segment_t; - -static inline mm_segment_t force_uaccess_begin(void) -{ - return (mm_segment_t) { }; -} - -static inline void force_uaccess_end(mm_segment_t oldfs) -{ -} -#endif /* CONFIG_SET_FS */ - /* * Architectures should provide two primitives (raw_copy_{to,from}_user()) * and get rid of their private instances of copy_{to,from}_user() and diff --git a/include/rdma/ib.h b/include/rdma/ib.h index 83139b9ce409..f7c185ff7a11 100644 --- a/include/rdma/ib.h +++ b/include/rdma/ib.h @@ -75,7 +75,7 @@ struct sockaddr_ib { */ static inline bool ib_safe_file_access(struct file *filp) { - return filp->f_cred == current_cred() && !uaccess_kernel(); + return filp->f_cred == current_cred(); } #endif /* _RDMA_IB_H */ diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index 58cbe357fb2b..1273be84392c 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -209,17 +209,13 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user, } if (regs) { - mm_segment_t fs; - if (crosstask) goto exit_put; if (add_mark) perf_callchain_store_context(&ctx, PERF_CONTEXT_USER); - fs = force_uaccess_begin(); perf_callchain_user(&ctx, regs); - force_uaccess_end(fs); } } diff --git a/kernel/events/core.c b/kernel/events/core.c index 57c7197838db..11ca7303d6df 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6746,7 +6746,6 @@ perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, unsigned long sp; unsigned int rem; u64 dyn_size; - mm_segment_t fs; /* * We dump: @@ -6764,9 +6763,7 @@ perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, /* Data. */ sp = perf_user_stack_pointer(regs); - fs = force_uaccess_begin(); rem = __output_copy_user(handle, (void *) sp, dump_size); - force_uaccess_end(fs); dyn_size = dump_size - rem; perf_output_skip(handle, rem); diff --git a/kernel/exit.c b/kernel/exit.c index b00a25bb4ab9..0884a75bc2f8 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -737,20 +737,6 @@ void __noreturn do_exit(long code) WARN_ON(blk_needs_flush_plug(tsk)); - /* - * If do_dead is called because this processes oopsed, it's possible - * that get_fs() was left as KERNEL_DS, so reset it to USER_DS before - * continuing. Amongst other possible reasons, this is to prevent - * mm_release()->clear_child_tid() from writing to a user-controlled - * kernel address. - * - * On uptodate architectures force_uaccess_begin is a noop. On - * architectures that still have set_fs/get_fs in addition to handling - * oopses handles kernel threads that run as set_fs(KERNEL_DS) by - * default. - */ - force_uaccess_begin(); - kcov_task_exit(tsk); coredump_task_exit(tsk); diff --git a/kernel/kthread.c b/kernel/kthread.c index 38c6dd822da8..16c2275d4b50 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -55,7 +55,6 @@ struct kthread { int result; int (*threadfn)(void *); void *data; - mm_segment_t oldfs; struct completion parked; struct completion exited; #ifdef CONFIG_BLK_CGROUP @@ -1441,8 +1440,6 @@ void kthread_use_mm(struct mm_struct *mm) mmdrop(active_mm); else smp_mb(); - - to_kthread(tsk)->oldfs = force_uaccess_begin(); } EXPORT_SYMBOL_GPL(kthread_use_mm); @@ -1457,8 +1454,6 @@ void kthread_unuse_mm(struct mm_struct *mm) WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD)); WARN_ON_ONCE(!tsk->mm); - force_uaccess_end(to_kthread(tsk)->oldfs); - task_lock(tsk); /* * When a kthread stops operating on an address space, the loop diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index 9c625257023d..9ed5ce989415 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -226,15 +226,12 @@ unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) .store = store, .size = size, }; - mm_segment_t fs; /* Trace user stack if not a kernel thread */ if (current->flags & PF_KTHREAD) return 0; - fs = force_uaccess_begin(); arch_stack_walk_user(consume_entry, &c, task_pt_regs(current)); - force_uaccess_end(fs); return c.len; } diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 21aa30644219..8115fff17018 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -332,8 +332,6 @@ BPF_CALL_3(bpf_probe_write_user, void __user *, unsafe_ptr, const void *, src, if (unlikely(in_interrupt() || current->flags & (PF_KTHREAD | PF_EXITING))) return -EPERM; - if (unlikely(uaccess_kernel())) - return -EPERM; if (unlikely(!nmi_uaccess_okay())) return -EPERM; @@ -835,8 +833,6 @@ static int bpf_send_signal_common(u32 sig, enum pid_type type) */ if (unlikely(current->flags & (PF_KTHREAD | PF_EXITING))) return -EPERM; - if (unlikely(uaccess_kernel())) - return -EPERM; if (unlikely(!nmi_uaccess_okay())) return -EPERM; diff --git a/mm/maccess.c b/mm/maccess.c index cbd1b3959af2..106820b33a2b 100644 --- a/mm/maccess.c +++ b/mm/maccess.c @@ -113,14 +113,11 @@ long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count) long copy_from_user_nofault(void *dst, const void __user *src, size_t size) { long ret = -EFAULT; - mm_segment_t old_fs = force_uaccess_begin(); - if (access_ok(src, size)) { pagefault_disable(); ret = __copy_from_user_inatomic(dst, src, size); pagefault_enable(); } - force_uaccess_end(old_fs); if (ret) return -EFAULT; @@ -140,14 +137,12 @@ EXPORT_SYMBOL_GPL(copy_from_user_nofault); long copy_to_user_nofault(void __user *dst, const void *src, size_t size) { long ret = -EFAULT; - mm_segment_t old_fs = force_uaccess_begin(); if (access_ok(dst, size)) { pagefault_disable(); ret = __copy_to_user_inatomic(dst, src, size); pagefault_enable(); } - force_uaccess_end(old_fs); if (ret) return -EFAULT; @@ -176,17 +171,14 @@ EXPORT_SYMBOL_GPL(copy_to_user_nofault); long strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr, long count) { - mm_segment_t old_fs; long ret; if (unlikely(count <= 0)) return 0; - old_fs = force_uaccess_begin(); pagefault_disable(); ret = strncpy_from_user(dst, unsafe_addr, count); pagefault_enable(); - force_uaccess_end(old_fs); if (ret >= count) { ret = count; @@ -216,14 +208,11 @@ long strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr, */ long strnlen_user_nofault(const void __user *unsafe_addr, long count) { - mm_segment_t old_fs; int ret; - old_fs = force_uaccess_begin(); pagefault_disable(); ret = strnlen_user(unsafe_addr, count); pagefault_enable(); - force_uaccess_end(old_fs); return ret; } diff --git a/mm/memory.c b/mm/memory.c index c125c4969913..9a6ebf68a846 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5256,14 +5256,6 @@ void print_vma_addr(char *prefix, unsigned long ip) #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP) void __might_fault(const char *file, int line) { - /* - * Some code (nfs/sunrpc) uses socket ops on kernel memory while - * holding the mmap_lock, this is safe because kernel memory doesn't - * get paged out, therefore we'll never actually fault, and the - * below annotations will generate false positives. - */ - if (uaccess_kernel()) - return; if (pagefault_disabled()) return; __might_sleep(file, line); diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c index 51a941b56ec3..422ec6e7ccff 100644 --- a/net/bpfilter/bpfilter_kern.c +++ b/net/bpfilter/bpfilter_kern.c @@ -70,7 +70,7 @@ static int bpfilter_process_sockopt(struct sock *sk, int optname, .addr = (uintptr_t)optval.user, .len = optlen, }; - if (uaccess_kernel() || sockptr_is_kernel(optval)) { + if (sockptr_is_kernel(optval)) { pr_err("kernel access not supported\n"); return -EFAULT; }