From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9A3943EF66F; Tue, 24 Mar 2026 11:42:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774352551; cv=none; b=SpTWAUxyCqgoKPItGAv0EHKpaGiMp5tbZw15vuj0SHPVdwwjK010Pfh6cpB2u5E9sQIfqJe5SpnlYoRctMLpkhfb7RfGR4LP34DanCsZ6cNwZ+ZhOFP6ndtLBmouk7+gDusn/OFq4i70bfnh1zq2nyWZegZDOgw3Kya411Vz8eA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774352551; c=relaxed/simple; bh=4PomMYzDixS1M/cpXZRiI8sfPTeQWI+OQgRyCHJzP8o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=brr9+VZ8NT+JpiLTvLBfnpr6GRTzkC9229tVjecC3QgABtpeslSakg4e/DP2BtxcjB+MlXoNSKZZXgL4uPb3KVf7xkxQC9dGZBsVaXtsjAIvpRNAR0VsNfSDybRP++OI8rA1qkrNKe16eYUSzuGwo70gpmGtd0fGSzTYEsYVtkc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EVTQpPm3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="EVTQpPm3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3437FC2BCB3; Tue, 24 Mar 2026 11:42:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774352551; bh=4PomMYzDixS1M/cpXZRiI8sfPTeQWI+OQgRyCHJzP8o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EVTQpPm3F58cE3VDg8q3SQE1k0p3aCTdkAJGoLD8xilQvtbouUc41vVhmy2BiGXsh h5XNCMkdhC3ZUyKeMK1+EEqZcGeG1qR9Y9XV4L1ZYxqh7g0KiueYwefOtrMh/QIpOJ /PC7407Tu8e/utoVf2N1JP5AEZQKJ9jhiKbKhHTrn2y8KlcvnWX3s7iYmmaQEX0oEU luU+EP6bE4X/sCOP6usEZMEIWVDKr+MiXFXY4RlGStPYBOfrIsOIn9OVY7fVRlzUZX FsfkTip+p2wkyiu4X+G/cve3Fc6CO7dAn3llbfGcpW9GYu6GtnwzJuKSAL+TpmCW6W cGAW4ZwzXheTA== From: "Christophe Leroy (CS GROUP)" To: Alexander Viro , Christian Brauner , Jan Kara , Linus Torvalds , Thomas Gleixner , David Laight Cc: "Christophe Leroy (CS GROUP)" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 2/2] fs: Replace user_access_{begin/end} by scoped user access Date: Tue, 24 Mar 2026 12:41:16 +0100 Message-ID: <16daf33a8190a771a93e294d050bd8153521ffca.1774350128.git.chleroy@kernel.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=8633; i=chleroy@kernel.org; h=from:subject:message-id; bh=4PomMYzDixS1M/cpXZRiI8sfPTeQWI+OQgRyCHJzP8o=; b=owGbwMvMwCV2d0KB2p7V54MZT6slMWQeqki+vTpr05qVbZsXqW97vNct91VOqXdmyXaZbwFnH misexre2lHKwiDGxSArpshy/D/3rhldX1Lzp+7Sh5nDygQyhIGLUwAmwv6d4Z/9rQonntkMoZpV NxeHGP/OqEoIrj22dX5m5GlPhmufPNkY/sf1zVJU7frTW/snesGHkxWnHaMzBQIThArPbGRU9d7 VyQkA X-Developer-Key: i=chleroy@kernel.org; a=openpgp; fpr=10FFE6F8B390DE17ACC2632368A92FEB01B8DD78 Content-Transfer-Encoding: 8bit Scoped user access reduces code complexity and seamlessly bring masked user access on architectures that support it. Replace user_access_begin/user_access_end blocks by scoped user access. Signed-off-by: Christophe Leroy (CS GROUP) --- v2: - Fix build failure with CONFIG_COMPAT - Handled checkpatch.pl output v3: - Fix again build failure with CONFIG_COMPAT. I was obviously too tired when I sent out v2. v4: - Introduced local size var based on Linus comment on readability. Not a dirent_size() helper as suggested as both sites are different. v5: - Just rely on the macro added in previous patch. --- fs/readdir.c | 88 +++++++++++++++++++++------------------------------- fs/select.c | 35 +++++++++------------ 2 files changed, 49 insertions(+), 74 deletions(-) diff --git a/fs/readdir.c b/fs/readdir.c index fb910dc2f52b..76bb1ae3a450 100644 --- a/fs/readdir.c +++ b/fs/readdir.c @@ -200,16 +200,13 @@ static bool fillonedir(struct dir_context *ctx, const char *name, int namlen, } buf->result++; dirent = buf->dirent; - if (!user_write_access_begin(dirent, dirent_size(dirent, namlen + 1))) - goto efault; - unsafe_put_user(d_ino, &dirent->d_ino, efault_end); - unsafe_put_user(offset, &dirent->d_offset, efault_end); - unsafe_put_user(namlen, &dirent->d_namlen, efault_end); - unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end); - user_write_access_end(); + scoped_user_write_access_size(dirent, dirent_size(dirent, namlen + 1), efault) { + unsafe_put_user(d_ino, &dirent->d_ino, efault); + unsafe_put_user(offset, &dirent->d_offset, efault); + unsafe_put_user(namlen, &dirent->d_namlen, efault); + unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault); + } return true; -efault_end: - user_write_access_end(); efault: buf->result = -EFAULT; return false; @@ -286,23 +283,19 @@ static bool filldir(struct dir_context *ctx, const char *name, int namlen, return false; dirent = buf->current_dir; prev = (void __user *) dirent - 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 */ - unsafe_put_user(offset, &prev->d_off, efault_end); - unsafe_put_user(d_ino, &dirent->d_ino, efault_end); - 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_write_access_end(); + scoped_user_write_access_size(prev, reclen + prev_reclen, efault) { + /* This might be 'dirent->d_off', but if so it will get overwritten */ + unsafe_put_user(offset, &prev->d_off, efault); + unsafe_put_user(d_ino, &dirent->d_ino, efault); + unsafe_put_user(reclen, &dirent->d_reclen, efault); + unsafe_put_user(d_type, (char __user *)dirent + reclen - 1, efault); + unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault); + } buf->current_dir = (void __user *)dirent + reclen; buf->prev_reclen = reclen; ctx->count -= reclen; return true; -efault_end: - user_write_access_end(); efault: buf->error = -EFAULT; return false; @@ -369,24 +362,20 @@ static bool filldir64(struct dir_context *ctx, const char *name, int namlen, return false; dirent = buf->current_dir; prev = (void __user *)dirent - 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 */ - unsafe_put_user(offset, &prev->d_off, efault_end); - unsafe_put_user(ino, &dirent->d_ino, efault_end); - 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_write_access_end(); + scoped_user_write_access_size(prev, reclen + prev_reclen, efault) { + /* This might be 'dirent->d_off', but if so it will get overwritten */ + unsafe_put_user(offset, &prev->d_off, efault); + unsafe_put_user(ino, &dirent->d_ino, efault); + unsafe_put_user(reclen, &dirent->d_reclen, efault); + unsafe_put_user(d_type, &dirent->d_type, efault); + unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault); + } buf->prev_reclen = reclen; buf->current_dir = (void __user *)dirent + reclen; ctx->count -= reclen; return true; -efault_end: - user_write_access_end(); efault: buf->error = -EFAULT; return false; @@ -458,16 +447,13 @@ static bool compat_fillonedir(struct dir_context *ctx, const char *name, } buf->result++; dirent = buf->dirent; - if (!user_write_access_begin(dirent, dirent_size(dirent, namlen + 1))) - goto efault; - unsafe_put_user(d_ino, &dirent->d_ino, efault_end); - unsafe_put_user(offset, &dirent->d_offset, efault_end); - unsafe_put_user(namlen, &dirent->d_namlen, efault_end); - unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault_end); - user_write_access_end(); + scoped_user_write_access_size(dirent, dirent_size(dirent, namlen + 1), efault) { + unsafe_put_user(d_ino, &dirent->d_ino, efault); + unsafe_put_user(offset, &dirent->d_offset, efault); + unsafe_put_user(namlen, &dirent->d_namlen, efault); + unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault); + } return true; -efault_end: - user_write_access_end(); efault: buf->result = -EFAULT; return false; @@ -538,22 +524,18 @@ static bool compat_filldir(struct dir_context *ctx, const char *name, int namlen return false; dirent = buf->current_dir; prev = (void __user *) dirent - prev_reclen; - if (!user_write_access_begin(prev, reclen + prev_reclen)) - goto efault; - - unsafe_put_user(offset, &prev->d_off, efault_end); - unsafe_put_user(d_ino, &dirent->d_ino, efault_end); - 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_write_access_end(); + scoped_user_write_access_size(prev, reclen + prev_reclen, efault) { + unsafe_put_user(offset, &prev->d_off, efault); + unsafe_put_user(d_ino, &dirent->d_ino, efault); + unsafe_put_user(reclen, &dirent->d_reclen, efault); + unsafe_put_user(d_type, (char __user *)dirent + reclen - 1, efault); + unsafe_copy_dirent_name(dirent->d_name, name, namlen, efault); + } buf->prev_reclen = reclen; buf->current_dir = (void __user *)dirent + reclen; ctx->count -= reclen; return true; -efault_end: - user_write_access_end(); efault: buf->error = -EFAULT; return false; diff --git a/fs/select.c b/fs/select.c index e0244dbe4429..75978b18f48f 100644 --- a/fs/select.c +++ b/fs/select.c @@ -1004,17 +1004,17 @@ static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, fdcount = do_poll(head, &table, end_time); poll_freewait(&table); - if (!user_write_access_begin(ufds, nfds * sizeof(*ufds))) - goto out_fds; + scoped_user_write_access_size(ufds, nfds * sizeof(*ufds), out_fds) { + struct pollfd __user *_ufds = ufds; - for (walk = head; walk; walk = walk->next) { - struct pollfd *fds = walk->entries; - unsigned int j; + for (walk = head; walk; walk = walk->next) { + struct pollfd *fds = walk->entries; + unsigned int j; - for (j = walk->len; j; fds++, ufds++, j--) - unsafe_put_user(fds->revents, &ufds->revents, Efault); - } - user_write_access_end(); + for (j = walk->len; j; fds++, _ufds++, j--) + unsafe_put_user(fds->revents, &_ufds->revents, out_fds); + } + } err = fdcount; out_fds: @@ -1026,11 +1026,6 @@ static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, } return err; - -Efault: - user_write_access_end(); - err = -EFAULT; - goto out_fds; } static long do_restart_poll(struct restart_block *restart_block) @@ -1338,15 +1333,13 @@ static inline int get_compat_sigset_argpack(struct compat_sigset_argpack *to, struct compat_sigset_argpack __user *from) { if (from) { - if (!user_read_access_begin(from, sizeof(*from))) - return -EFAULT; - unsafe_get_user(to->p, &from->p, Efault); - unsafe_get_user(to->size, &from->size, Efault); - user_read_access_end(); + scoped_user_read_access(from, efault) { + unsafe_get_user(to->p, &from->p, efault); + unsafe_get_user(to->size, &from->size, efault); + } } return 0; -Efault: - user_read_access_end(); +efault: return -EFAULT; } -- 2.49.0