[PATCH 01/32] pidfs: validate extensible ioctls
From: Christian Brauner <brauner@kernel.org>
Date: 2025-09-10 14:37:11
Also in:
cgroups, linux-block, linux-fsdevel, linux-kselftest, linux-nfs, lkml
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
Validate extensible ioctls stricter than we do now. Signed-off-by: Christian Brauner <brauner@kernel.org> --- fs/pidfs.c | 2 +- include/linux/fs.h | 14 ++++++++++++++ 2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/fs/pidfs.c b/fs/pidfs.c
index edc35522d75c..0a5083b9cce5 100644
--- a/fs/pidfs.c
+++ b/fs/pidfs.c@@ -440,7 +440,7 @@ static bool pidfs_ioctl_valid(unsigned int cmd) * erronously mistook the file descriptor for a pidfd. * This is not perfect but will catch most cases. */ - return (_IOC_TYPE(cmd) == _IOC_TYPE(PIDFD_GET_INFO)); + return extensible_ioctl_valid(cmd, PIDFD_GET_INFO, PIDFD_INFO_SIZE_VER0); } return false;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d7ab4f96d705..2f2edc53bf3c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h@@ -4023,4 +4023,18 @@ static inline bool vfs_empty_path(int dfd, const char __user *path) int generic_atomic_write_valid(struct kiocb *iocb, struct iov_iter *iter); +static inline bool extensible_ioctl_valid(unsigned int cmd_a, + unsigned int cmd_b, size_t min_size) +{ + if (_IOC_DIR(cmd_a) != _IOC_DIR(cmd_b)) + return false; + if (_IOC_TYPE(cmd_a) != _IOC_TYPE(cmd_b)) + return false; + if (_IOC_NR(cmd_a) != _IOC_NR(cmd_b)) + return false; + if (_IOC_SIZE(cmd_a) < min_size) + return false; + return true; +} + #endif /* _LINUX_FS_H */
--
2.47.3