From mboxrd@z Thu Jan 1 00:00:00 1970 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=-10.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 3E217C43461 for ; Thu, 3 Sep 2020 17:48:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E008C2072A for ; Thu, 3 Sep 2020 17:48:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E008C2072A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=bitdefender.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id AC3CD900002; Thu, 3 Sep 2020 13:48:15 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A26118E0005; Thu, 3 Sep 2020 13:48:15 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8C9BB900002; Thu, 3 Sep 2020 13:48:15 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0031.hostedemail.com [216.40.44.31]) by kanga.kvack.org (Postfix) with ESMTP id 640228E0005 for ; Thu, 3 Sep 2020 13:48:15 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 22FD3824C739 for ; Thu, 3 Sep 2020 17:48:15 +0000 (UTC) X-FDA: 77222484150.08.grade42_3600b15270ab Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin08.hostedemail.com (Postfix) with ESMTP id EB8BA1819E764 for ; Thu, 3 Sep 2020 17:48:14 +0000 (UTC) X-HE-Tag: grade42_3600b15270ab X-Filterd-Recvd-Size: 7075 Received: from mx01.bbu.dsd.mx.bitdefender.com (mx01.bbu.dsd.mx.bitdefender.com [91.199.104.161]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Thu, 3 Sep 2020 17:48:14 +0000 (UTC) Received: from smtp.bitdefender.com (smtp01.buh.bitdefender.com [10.17.80.75]) by mx01.bbu.dsd.mx.bitdefender.com (Postfix) with ESMTPS id C447F307C935; Thu, 3 Sep 2020 20:48:09 +0300 (EEST) Received: from localhost.localdomain (unknown [195.189.155.252]) by smtp.bitdefender.com (Postfix) with ESMTPSA id 9456F3072786; Thu, 3 Sep 2020 20:48:09 +0300 (EEST) From: =?UTF-8?q?Adalbert=20Laz=C4=83r?= To: linux-mm@kvack.org Cc: Andrew Morton , Alexander Graf , Stefan Hajnoczi , Jerome Glisse , Paolo Bonzini , Mircea Cirjaliu , Christian Brauner , =?UTF-8?q?Adalbert=20Laz=C4=83r?= Subject: [RFC PATCH 5/5] pidfd_mem: implemented remote memory mapping system call Date: Thu, 3 Sep 2020 20:47:30 +0300 Message-Id: <20200903174730.2685-6-alazar@bitdefender.com> In-Reply-To: <20200903174730.2685-1-alazar@bitdefender.com> References: <20200903174730.2685-1-alazar@bitdefender.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Rspamd-Queue-Id: EB8BA1819E764 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Mircea Cirjaliu This system call returns 2 fds for inspecting the address space of a remote process: one for control and one for access. Use according to remote mapping specifications. Cc: Christian Brauner Signed-off-by: Mircea Cirjaliu Signed-off-by: Adalbert Laz=C4=83r --- arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + include/linux/pid.h | 1 + include/linux/syscalls.h | 1 + include/uapi/asm-generic/unistd.h | 2 + kernel/exit.c | 2 +- kernel/pid.c | 55 ++++++++++++++++++++++++++ 7 files changed, 62 insertions(+), 1 deletion(-) diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/sysc= alls/syscall_32.tbl index 54581ac671b4..ca1b5a32dbc5 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -440,5 +440,6 @@ 433 i386 fspick sys_fspick 434 i386 pidfd_open sys_pidfd_open 435 i386 clone3 sys_clone3 +436 i386 pidfd_mem sys_pidfd_mem 437 i386 openat2 sys_openat2 438 i386 pidfd_getfd sys_pidfd_getfd diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/sysc= alls/syscall_64.tbl index 37b844f839bc..6138d3d023f8 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -357,6 +357,7 @@ 433 common fspick sys_fspick 434 common pidfd_open sys_pidfd_open 435 common clone3 sys_clone3 +436 common pidfd_mem sys_pidfd_mem 437 common openat2 sys_openat2 438 common pidfd_getfd sys_pidfd_getfd =20 diff --git a/include/linux/pid.h b/include/linux/pid.h index cc896f0fc4e3..9ec23ab23fd4 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -76,6 +76,7 @@ extern const struct file_operations pidfd_fops; =20 struct file; =20 +extern struct pid *pidfd_get_pid(unsigned int fd); extern struct pid *pidfd_pid(const struct file *file); =20 static inline struct pid *get_pid(struct pid *pid) diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 1815065d52f3..621f3d52ed4e 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -934,6 +934,7 @@ asmlinkage long sys_clock_adjtime32(clockid_t which_c= lock, asmlinkage long sys_syncfs(int fd); asmlinkage long sys_setns(int fd, int nstype); asmlinkage long sys_pidfd_open(pid_t pid, unsigned int flags); +asmlinkage long sys_pidfd_mem(int pidfd, int __user *fds, unsigned int f= lags); asmlinkage long sys_sendmmsg(int fd, struct mmsghdr __user *msg, unsigned int vlen, unsigned flags); asmlinkage long sys_process_vm_readv(pid_t pid, diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic= /unistd.h index 3a3201e4618e..2663afc03c86 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -850,6 +850,8 @@ __SYSCALL(__NR_pidfd_open, sys_pidfd_open) #define __NR_clone3 435 __SYSCALL(__NR_clone3, sys_clone3) #endif +#define __NR_pidfd_mem 436 +__SYSCALL(__NR_pidfd_mem, sys_pidfd_mem) =20 #define __NR_openat2 437 __SYSCALL(__NR_openat2, sys_openat2) diff --git a/kernel/exit.c b/kernel/exit.c index 389a88cb3081..37cd8949e606 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1464,7 +1464,7 @@ static long do_wait(struct wait_opts *wo) return retval; } =20 -static struct pid *pidfd_get_pid(unsigned int fd) +struct pid *pidfd_get_pid(unsigned int fd) { struct fd f; struct pid *pid; diff --git a/kernel/pid.c b/kernel/pid.c index c835b844aca7..c9c49edf4a8a 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -42,6 +42,7 @@ #include #include #include +#include =20 struct pid init_struct_pid =3D { .count =3D REFCOUNT_INIT(1), @@ -565,6 +566,60 @@ SYSCALL_DEFINE2(pidfd_open, pid_t, pid, unsigned int= , flags) return fd; } =20 +/** + * pidfd_mem() - Allow access to process address space. + * + * @pidfd: pid file descriptor for the target process + * @fds: array where the control and access file descriptors are retur= ned + * @flags: flags to pass + * + * This creates a pair of file descriptors used to gain access to the + * target process memory. The control fd is used to establish a linear + * mapping between an offset range and a userspace address range. + * The access fd is used to mmap(offset range) on the client side. + * + * Return: On success, 0 is returned. + * On error, a negative errno number will be returned. + */ +SYSCALL_DEFINE3(pidfd_mem, int, pidfd, int __user *, fds, unsigned int, = flags) +{ + struct pid *pid; + struct task_struct *task; + int ret_fds[2]; + int ret; + + if (pidfd < 0) + return -EINVAL; + if (!fds) + return -EINVAL; + if (flags) + return -EINVAL; + + pid =3D pidfd_get_pid(pidfd); + if (IS_ERR(pid)) + return PTR_ERR(pid); + + task =3D get_pid_task(pid, PIDTYPE_PID); + put_pid(pid); + if (IS_ERR(task)) + return PTR_ERR(task); + + ret =3D -EPERM; + if (unlikely(task =3D=3D current) || capable(CAP_SYS_PTRACE)) + ret =3D task_remote_map(task, ret_fds); + put_task_struct(task); + if (IS_ERR_VALUE((long)ret)) + return ret; + + if (copy_to_user(fds, ret_fds, sizeof(ret_fds))) { + put_unused_fd(ret_fds[0]); + put_unused_fd(ret_fds[1]); + return -EFAULT; + } + + return 0; +} + void __init pid_idr_init(void) { /* Verify no one has done anything silly: */