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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 3B759C433E0 for ; Thu, 28 May 2020 23:50:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 142FC2075F for ; Thu, 28 May 2020 23:50:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437817AbgE1XuY (ORCPT ); Thu, 28 May 2020 19:50:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44834 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2437780AbgE1Xtd (ORCPT ); Thu, 28 May 2020 19:49:33 -0400 Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [IPv6:2002:c35c:fd02::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 996DAC008630; Thu, 28 May 2020 16:49:33 -0700 (PDT) Received: from viro by ZenIV.linux.org.uk with local (Exim 4.93 #3 (Red Hat Linux)) id 1jeSHE-00HDpK-2l; Thu, 28 May 2020 23:49:32 +0000 From: Al Viro To: Linus Torvalds Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 2/6] uaccess: Selectively open read or write user access Date: Fri, 29 May 2020 00:49:30 +0100 Message-Id: <20200528234931.4104686-2-viro@ZenIV.linux.org.uk> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20200528234931.4104686-1-viro@ZenIV.linux.org.uk> References: <20200528234025.GT23230@ZenIV.linux.org.uk> <20200528234931.4104686-1-viro@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Christophe Leroy When opening user access to only perform reads, only open read access. When opening user access to only perform writes, only open write access. Signed-off-by: Christophe Leroy Reviewed-by: Kees Cook Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/2e73bc57125c2c6ab12a587586a4eed3a47105fc.1585898438.git.christophe.leroy@c-s.fr --- fs/readdir.c | 12 ++++++------ kernel/compat.c | 12 ++++++------ kernel/exit.c | 12 ++++++------ lib/strncpy_from_user.c | 4 ++-- lib/strnlen_user.c | 4 ++-- lib/usercopy.c | 6 +++--- 6 files changed, 25 insertions(+), 25 deletions(-) diff --git a/fs/readdir.c b/fs/readdir.c index de2eceffdee8..ed6aaad451aa 100644 --- a/fs/readdir.c +++ b/fs/readdir.c @@ -242,7 +242,7 @@ static int filldir(struct dir_context *ctx, const char *name, int namlen, return -EINTR; dirent = buf->current_dir; prev = (void __user *) dirent - prev_reclen; - if (!user_access_begin(prev, reclen + prev_reclen)) + if (!user_write_access_begin(prev, reclen + prev_reclen)) goto efault; /* This might be 'dirent->d_off', but if so it will get overwritten */ @@ -251,14 +251,14 @@ static int filldir(struct dir_context *ctx, const char *name, int namlen, unsafe_put_user(reclen, &dirent->d_reclen, efault_end); unsafe_put_user(d_type, (char __user *) dirent + reclen - 1, efault_end); unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end); - user_access_end(); + user_write_access_end(); buf->current_dir = (void __user *)dirent + reclen; buf->prev_reclen = reclen; buf->count -= reclen; return 0; efault_end: - user_access_end(); + user_write_access_end(); efault: buf->error = -EFAULT; return -EFAULT; @@ -327,7 +327,7 @@ static int filldir64(struct dir_context *ctx, const char *name, int namlen, return -EINTR; dirent = buf->current_dir; prev = (void __user *)dirent - prev_reclen; - if (!user_access_begin(prev, reclen + prev_reclen)) + if (!user_write_access_begin(prev, reclen + prev_reclen)) goto efault; /* This might be 'dirent->d_off', but if so it will get overwritten */ @@ -336,7 +336,7 @@ static int filldir64(struct dir_context *ctx, const char *name, int namlen, unsafe_put_user(reclen, &dirent->d_reclen, efault_end); unsafe_put_user(d_type, &dirent->d_type, efault_end); unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end); - user_access_end(); + user_write_access_end(); buf->prev_reclen = reclen; buf->current_dir = (void __user *)dirent + reclen; @@ -344,7 +344,7 @@ static int filldir64(struct dir_context *ctx, const char *name, int namlen, return 0; efault_end: - user_access_end(); + user_write_access_end(); efault: buf->error = -EFAULT; return -EFAULT; diff --git a/kernel/compat.c b/kernel/compat.c index 843dd17e6078..b8d2800bb4b7 100644 --- a/kernel/compat.c +++ b/kernel/compat.c @@ -199,7 +199,7 @@ long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask, bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG); nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size); - if (!user_access_begin(umask, bitmap_size / 8)) + if (!user_read_access_begin(umask, bitmap_size / 8)) return -EFAULT; while (nr_compat_longs > 1) { @@ -211,11 +211,11 @@ long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask, } if (nr_compat_longs) unsafe_get_user(*mask, umask++, Efault); - user_access_end(); + user_read_access_end(); return 0; Efault: - user_access_end(); + user_read_access_end(); return -EFAULT; } @@ -228,7 +228,7 @@ long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask, bitmap_size = ALIGN(bitmap_size, BITS_PER_COMPAT_LONG); nr_compat_longs = BITS_TO_COMPAT_LONGS(bitmap_size); - if (!user_access_begin(umask, bitmap_size / 8)) + if (!user_write_access_begin(umask, bitmap_size / 8)) return -EFAULT; while (nr_compat_longs > 1) { @@ -239,10 +239,10 @@ long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask, } if (nr_compat_longs) unsafe_put_user((compat_ulong_t)*mask, umask++, Efault); - user_access_end(); + user_write_access_end(); return 0; Efault: - user_access_end(); + user_write_access_end(); return -EFAULT; } diff --git a/kernel/exit.c b/kernel/exit.c index 389a88cb3081..2d97cbba512d 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1557,7 +1557,7 @@ SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *, if (!infop) return err; - if (!user_access_begin(infop, sizeof(*infop))) + if (!user_write_access_begin(infop, sizeof(*infop))) return -EFAULT; unsafe_put_user(signo, &infop->si_signo, Efault); @@ -1566,10 +1566,10 @@ SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *, unsafe_put_user(info.pid, &infop->si_pid, Efault); unsafe_put_user(info.uid, &infop->si_uid, Efault); unsafe_put_user(info.status, &infop->si_status, Efault); - user_access_end(); + user_write_access_end(); return err; Efault: - user_access_end(); + user_write_access_end(); return -EFAULT; } @@ -1684,7 +1684,7 @@ COMPAT_SYSCALL_DEFINE5(waitid, if (!infop) return err; - if (!user_access_begin(infop, sizeof(*infop))) + if (!user_write_access_begin(infop, sizeof(*infop))) return -EFAULT; unsafe_put_user(signo, &infop->si_signo, Efault); @@ -1693,10 +1693,10 @@ COMPAT_SYSCALL_DEFINE5(waitid, unsafe_put_user(info.pid, &infop->si_pid, Efault); unsafe_put_user(info.uid, &infop->si_uid, Efault); unsafe_put_user(info.status, &infop->si_status, Efault); - user_access_end(); + user_write_access_end(); return err; Efault: - user_access_end(); + user_write_access_end(); return -EFAULT; } #endif diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c index 706020b06617..b90ec550183a 100644 --- a/lib/strncpy_from_user.c +++ b/lib/strncpy_from_user.c @@ -116,9 +116,9 @@ long strncpy_from_user(char *dst, const char __user *src, long count) kasan_check_write(dst, count); check_object_size(dst, count, false); - if (user_access_begin(src, max)) { + if (user_read_access_begin(src, max)) { retval = do_strncpy_from_user(dst, src, count, max); - user_access_end(); + user_read_access_end(); return retval; } } diff --git a/lib/strnlen_user.c b/lib/strnlen_user.c index 41670d4a5816..1616710b8a82 100644 --- a/lib/strnlen_user.c +++ b/lib/strnlen_user.c @@ -109,9 +109,9 @@ long strnlen_user(const char __user *str, long count) if (max > count) max = count; - if (user_access_begin(str, max)) { + if (user_read_access_begin(str, max)) { retval = do_strnlen_user(str, count, max); - user_access_end(); + user_read_access_end(); return retval; } } diff --git a/lib/usercopy.c b/lib/usercopy.c index cbb4d9ec00f2..ca2a697a2061 100644 --- a/lib/usercopy.c +++ b/lib/usercopy.c @@ -58,7 +58,7 @@ int check_zeroed_user(const void __user *from, size_t size) from -= align; size += align; - if (!user_access_begin(from, size)) + if (!user_read_access_begin(from, size)) return -EFAULT; unsafe_get_user(val, (unsigned long __user *) from, err_fault); @@ -79,10 +79,10 @@ int check_zeroed_user(const void __user *from, size_t size) val &= aligned_byte_mask(size); done: - user_access_end(); + user_read_access_end(); return (val == 0); err_fault: - user_access_end(); + user_read_access_end(); return -EFAULT; } EXPORT_SYMBOL(check_zeroed_user); -- 2.11.0