From 7fd511f8c911ab6ffb49357d5cd8ef493f28c921 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Wed, 19 Feb 2025 17:40:28 +0100 Subject: [PATCH 1/2] nsfs: validate ioctls Nsfs supports extensible and non-extensible ioctls. Validate both types to prevent confusion. Link: https://lore.kernel.org/r/20250219-work-nsfs-v1-1-21128d73c5e8@kernel.org Reviewed-by: Jeff Layton Signed-off-by: Christian Brauner --- fs/nsfs.c | 32 +++++++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-) diff --git a/fs/nsfs.c b/fs/nsfs.c index 663f8656158d..1ab705bb9386 100644 --- a/fs/nsfs.c +++ b/fs/nsfs.c @@ -152,19 +152,49 @@ static int copy_ns_info_to_user(const struct mnt_namespace *mnt_ns, return 0; } +static bool nsfs_ioctl_valid(unsigned int cmd) +{ + switch (cmd) { + case NS_GET_USERNS: + case NS_GET_PARENT: + case NS_GET_NSTYPE: + case NS_GET_OWNER_UID: + case NS_GET_MNTNS_ID: + case NS_GET_PID_FROM_PIDNS: + case NS_GET_TGID_FROM_PIDNS: + case NS_GET_PID_IN_PIDNS: + case NS_GET_TGID_IN_PIDNS: + return (_IOC_TYPE(cmd) == _IOC_TYPE(cmd)); + } + + /* Extensible ioctls require some extra handling. */ + switch (_IOC_NR(cmd)) { + case _IOC_NR(NS_MNT_GET_INFO): + case _IOC_NR(NS_MNT_GET_NEXT): + case _IOC_NR(NS_MNT_GET_PREV): + return (_IOC_TYPE(cmd) == _IOC_TYPE(cmd)); + } + + return false; +} + static long ns_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) { struct user_namespace *user_ns; struct pid_namespace *pid_ns; struct task_struct *tsk; - struct ns_common *ns = get_proc_ns(file_inode(filp)); + struct ns_common *ns; struct mnt_namespace *mnt_ns; bool previous = false; uid_t __user *argp; uid_t uid; int ret; + if (!nsfs_ioctl_valid(ioctl)) + return -ENOIOCTLCMD; + + ns = get_proc_ns(file_inode(filp)); switch (ioctl) { case NS_GET_USERNS: return open_related_ns(ns, ns_get_owner); From 540dcf0f44042fd9c6e14ae863efb67780ae0084 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Wed, 19 Feb 2025 17:40:29 +0100 Subject: [PATCH 2/2] selftests/nsfs: add ioctl validation tests Add simple tests to validate that non-nsfs ioctls are rejected. Link: https://lore.kernel.org/r/20250219-work-nsfs-v1-2-21128d73c5e8@kernel.org Reviewed-by: Jeff Layton Signed-off-by: Christian Brauner --- .../selftests/filesystems/nsfs/iterate_mntns.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/tools/testing/selftests/filesystems/nsfs/iterate_mntns.c b/tools/testing/selftests/filesystems/nsfs/iterate_mntns.c index 457cf76f3c5f..a3d8015897e9 100644 --- a/tools/testing/selftests/filesystems/nsfs/iterate_mntns.c +++ b/tools/testing/selftests/filesystems/nsfs/iterate_mntns.c @@ -3,6 +3,8 @@ #define _GNU_SOURCE #include +#include +#include #include #include #include @@ -146,4 +148,16 @@ TEST_F(iterate_mount_namespaces, iterate_backward) } } +TEST_F(iterate_mount_namespaces, nfs_valid_ioctl) +{ + ASSERT_NE(ioctl(self->fd_mnt_ns[0], AUTOFS_DEV_IOCTL_OPENMOUNT, NULL), 0); + ASSERT_EQ(errno, ENOTTY); + + ASSERT_NE(ioctl(self->fd_mnt_ns[0], AUTOFS_DEV_IOCTL_CLOSEMOUNT, NULL), 0); + ASSERT_EQ(errno, ENOTTY); + + ASSERT_NE(ioctl(self->fd_mnt_ns[0], AUTOFS_DEV_IOCTL_READY, NULL), 0); + ASSERT_EQ(errno, ENOTTY); +} + TEST_HARNESS_MAIN