Validate extensible ioctls stricter than we do now.
Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
---
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
