From: "Mickaël Salaün" <mic@digikod.net>
To: "Arnd Bergmann" <arnd@arndb.de>,
"Christian Brauner" <brauner@kernel.org>,
"Günther Noack" <gnoack@google.com>
Cc: "Mickaël Salaün" <mic@digikod.net>,
"Allen Webb" <allenwebb@google.com>,
"Dmitry Torokhov" <dtor@google.com>,
"Jeff Xu" <jeffxu@google.com>,
"Jorge Lucangeli Obes" <jorgelo@chromium.org>,
"Konstantin Meskhidze" <konstantin.meskhidze@huawei.com>,
"Matt Bobrowski" <repnop@google.com>,
"Paul Moore" <paul@paul-moore.com>,
linux-fsdevel@vger.kernel.org,
linux-security-module@vger.kernel.org
Subject: [RFC PATCH] fs: Add vfs_masks_device_ioctl*() helpers
Date: Mon, 19 Feb 2024 19:35:39 +0100 [thread overview]
Message-ID: <20240219183539.2926165-1-mic@digikod.net> (raw)
In-Reply-To: <20240219.chu4Yeegh3oo@digikod.net>
vfs_masks_device_ioctl() and vfs_masks_device_ioctl_compat() are useful
to differenciate between device driver IOCTL implementations and
filesystem ones. The goal is to be able to filter well-defined IOCTLs
from per-device (i.e. namespaced) IOCTLs and control such access.
Add a new ioctl_compat() helper, similar to vfs_ioctl(), to wrap
compat_ioctl() calls and handle error conversions.
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Günther Noack <gnoack@google.com>
---
fs/ioctl.c | 101 +++++++++++++++++++++++++++++++++++++++++----
include/linux/fs.h | 12 ++++++
2 files changed, 105 insertions(+), 8 deletions(-)
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 76cf22ac97d7..f72c8da47d21 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -763,6 +763,38 @@ static int ioctl_fssetxattr(struct file *file, void __user *argp)
return err;
}
+/*
+ * Safeguard to maintain a list of valid IOCTLs handled by do_vfs_ioctl()
+ * instead of def_blk_fops or def_chr_fops (see init_special_inode).
+ */
+__attribute_const__ bool vfs_masked_device_ioctl(const unsigned int cmd)
+{
+ switch (cmd) {
+ case FIOCLEX:
+ case FIONCLEX:
+ case FIONBIO:
+ case FIOASYNC:
+ case FIOQSIZE:
+ case FIFREEZE:
+ case FITHAW:
+ case FS_IOC_FIEMAP:
+ case FIGETBSZ:
+ case FICLONE:
+ case FICLONERANGE:
+ case FIDEDUPERANGE:
+ /* FIONREAD is forwarded to device implementations. */
+ case FS_IOC_GETFLAGS:
+ case FS_IOC_SETFLAGS:
+ case FS_IOC_FSGETXATTR:
+ case FS_IOC_FSSETXATTR:
+ /* file_ioctl()'s IOCTLs are forwarded to device implementations. */
+ return true;
+ default:
+ return false;
+ }
+}
+EXPORT_SYMBOL(vfs_masked_device_ioctl);
+
/*
* do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
* It's just a simple helper for sys_ioctl and compat_sys_ioctl.
@@ -858,6 +890,8 @@ SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
{
struct fd f = fdget(fd);
int error;
+ const struct inode *inode;
+ bool is_device;
if (!f.file)
return -EBADF;
@@ -866,9 +900,18 @@ SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
if (error)
goto out;
+ inode = file_inode(f.file);
+ is_device = S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode);
+ if (is_device && !vfs_masked_device_ioctl(cmd)) {
+ error = vfs_ioctl(f.file, cmd, arg);
+ goto out;
+ }
+
error = do_vfs_ioctl(f.file, fd, cmd, arg);
- if (error == -ENOIOCTLCMD)
+ if (error == -ENOIOCTLCMD) {
+ WARN_ON_ONCE(is_device);
error = vfs_ioctl(f.file, cmd, arg);
+ }
out:
fdput(f);
@@ -911,11 +954,49 @@ long compat_ptr_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
}
EXPORT_SYMBOL(compat_ptr_ioctl);
+static long ioctl_compat(struct file *filp, unsigned int cmd,
+ compat_ulong_t arg)
+{
+ int error = -ENOTTY;
+
+ if (!filp->f_op->compat_ioctl)
+ goto out;
+
+ error = filp->f_op->compat_ioctl(filp, cmd, arg);
+ if (error == -ENOIOCTLCMD)
+ error = -ENOTTY;
+
+out:
+ return error;
+}
+
+__attribute_const__ bool vfs_masked_device_ioctl_compat(const unsigned int cmd)
+{
+ switch (cmd) {
+ case FICLONE:
+#if defined(CONFIG_X86_64)
+ case FS_IOC_RESVSP_32:
+ case FS_IOC_RESVSP64_32:
+ case FS_IOC_UNRESVSP_32:
+ case FS_IOC_UNRESVSP64_32:
+ case FS_IOC_ZERO_RANGE_32:
+#endif
+ case FS_IOC32_GETFLAGS:
+ case FS_IOC32_SETFLAGS:
+ return true;
+ default:
+ return vfs_masked_device_ioctl(cmd);
+ }
+}
+EXPORT_SYMBOL(vfs_masked_device_ioctl_compat);
+
COMPAT_SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd,
compat_ulong_t, arg)
{
struct fd f = fdget(fd);
int error;
+ const struct inode *inode;
+ bool is_device;
if (!f.file)
return -EBADF;
@@ -924,6 +1005,13 @@ COMPAT_SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd,
if (error)
goto out;
+ inode = file_inode(f.file);
+ is_device = S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode);
+ if (is_device && !vfs_masked_device_ioctl_compat(cmd)) {
+ error = ioctl_compat(f.file, cmd, arg);
+ goto out;
+ }
+
switch (cmd) {
/* FICLONE takes an int argument, so don't use compat_ptr() */
case FICLONE:
@@ -964,13 +1052,10 @@ COMPAT_SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd,
default:
error = do_vfs_ioctl(f.file, fd, cmd,
(unsigned long)compat_ptr(arg));
- if (error != -ENOIOCTLCMD)
- break;
-
- if (f.file->f_op->compat_ioctl)
- error = f.file->f_op->compat_ioctl(f.file, cmd, arg);
- if (error == -ENOIOCTLCMD)
- error = -ENOTTY;
+ if (error == -ENOIOCTLCMD) {
+ WARN_ON_ONCE(is_device);
+ error = ioctl_compat(f.file, cmd, arg);
+ }
break;
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index ed5966a70495..b620d0c00e16 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1902,6 +1902,18 @@ extern long compat_ptr_ioctl(struct file *file, unsigned int cmd,
#define compat_ptr_ioctl NULL
#endif
+extern __attribute_const__ bool vfs_masked_device_ioctl(const unsigned int cmd);
+#ifdef CONFIG_COMPAT
+extern __attribute_const__ bool
+vfs_masked_device_ioctl_compat(const unsigned int cmd);
+#else /* CONFIG_COMPAT */
+static inline __attribute_const__ bool
+vfs_masked_device_ioctl_compat(const unsigned int cmd)
+{
+ return vfs_masked_device_ioctl(cmd);
+}
+#endif /* CONFIG_COMPAT */
+
/*
* VFS file helper functions.
*/
--
2.43.0
next prev parent reply other threads:[~2024-02-19 18:42 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-09 17:06 [PATCH v9 0/8] Landlock: IOCTL support Günther Noack
2024-02-09 17:06 ` [PATCH v9 1/8] landlock: Add IOCTL access right Günther Noack
2024-02-10 11:06 ` Günther Noack
2024-02-10 11:49 ` Arnd Bergmann
2024-02-12 11:09 ` Christian Brauner
2024-02-12 22:10 ` Günther Noack
2024-02-10 11:18 ` Günther Noack
2024-02-16 14:11 ` Mickaël Salaün
2024-02-16 15:51 ` Mickaël Salaün
2024-02-18 8:34 ` Günther Noack
2024-02-19 21:44 ` Günther Noack
2024-02-16 17:19 ` Mickaël Salaün
2024-02-19 18:34 ` Mickaël Salaün
2024-02-19 18:35 ` Mickaël Salaün [this message]
2024-03-01 13:42 ` [RFC PATCH] fs: Add vfs_masks_device_ioctl*() helpers Mickaël Salaün
2024-03-01 16:24 ` Arnd Bergmann
2024-03-01 18:35 ` Mickaël Salaün
2024-03-05 18:13 ` Günther Noack
2024-03-06 13:47 ` Mickaël Salaün
2024-03-06 15:18 ` Arnd Bergmann
2024-03-07 12:15 ` Christian Brauner
2024-03-07 12:21 ` Arnd Bergmann
2024-03-07 12:57 ` Günther Noack
2024-03-07 20:40 ` Paul Moore
2024-03-07 23:09 ` Dave Chinner
2024-03-07 23:35 ` Paul Moore
2024-03-08 7:02 ` Arnd Bergmann
2024-03-08 9:29 ` Mickaël Salaün
2024-03-08 19:22 ` Paul Moore
2024-03-08 20:12 ` Mickaël Salaün
2024-03-08 22:04 ` Casey Schaufler
2024-03-08 22:25 ` Paul Moore
2024-03-09 8:14 ` Günther Noack
2024-03-09 17:41 ` Casey Schaufler
2024-03-11 19:04 ` Paul Moore
2024-03-08 11:03 ` Günther Noack
2024-03-11 1:03 ` Dave Chinner
2024-03-11 9:01 ` Günther Noack
2024-03-11 22:12 ` Dave Chinner
2024-03-12 10:58 ` Mickaël Salaün
2024-02-28 12:57 ` [PATCH v9 1/8] landlock: Add IOCTL access right Günther Noack
2024-03-01 12:59 ` Mickaël Salaün
2024-03-01 13:38 ` Mickaël Salaün
2024-02-09 17:06 ` [PATCH v9 2/8] selftests/landlock: Test IOCTL support Günther Noack
2024-02-09 17:06 ` [PATCH v9 3/8] selftests/landlock: Test IOCTL with memfds Günther Noack
2024-02-09 17:06 ` [PATCH v9 4/8] selftests/landlock: Test ioctl(2) and ftruncate(2) with open(O_PATH) Günther Noack
2024-02-09 17:06 ` [PATCH v9 5/8] selftests/landlock: Test IOCTLs on named pipes Günther Noack
2024-02-09 17:06 ` [PATCH v9 6/8] selftests/landlock: Check IOCTL restrictions for named UNIX domain sockets Günther Noack
2024-02-09 17:06 ` [PATCH v9 7/8] samples/landlock: Add support for LANDLOCK_ACCESS_FS_IOCTL Günther Noack
2024-02-09 17:06 ` [PATCH v9 8/8] landlock: Document IOCTL support Günther Noack
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240219183539.2926165-1-mic@digikod.net \
--to=mic@digikod.net \
--cc=allenwebb@google.com \
--cc=arnd@arndb.de \
--cc=brauner@kernel.org \
--cc=dtor@google.com \
--cc=gnoack@google.com \
--cc=jeffxu@google.com \
--cc=jorgelo@chromium.org \
--cc=konstantin.meskhidze@huawei.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=paul@paul-moore.com \
--cc=repnop@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).