From ad737fda8c44e78ced5864e798a8ba23b1a3c3f9 Mon Sep 17 00:00:00 2001 From: Wenwen Wang Date: Mon, 7 May 2018 19:46:43 -0500 Subject: [PATCH] scsi: 3w-9xxx: fix a missing-check bug BugLink: http://bugs.launchpad.net/bugs/1815234 [ Upstream commit c9318a3e0218bc9dacc25be46b9eec363259536f ] In twa_chrdev_ioctl(), the ioctl driver command is firstly copied from the userspace pointer 'argp' and saved to the kernel object 'driver_command'. Then a security check is performed on the data buffer size indicated by 'driver_command', which is 'driver_command.buffer_length'. If the security check is passed, the entire ioctl command is copied again from the 'argp' pointer and saved to the kernel object 'tw_ioctl'. Then, various operations are performed on 'tw_ioctl' according to the 'cmd'. Given that the 'argp' pointer resides in userspace, a malicious userspace process can race to change the buffer size between the two copies. This way, the user can bypass the security check and inject invalid data buffer size. This can cause potential security issues in the following execution. This patch checks for capable(CAP_SYS_ADMIN) in twa_chrdev_open()t o avoid the above issues. Signed-off-by: Wenwen Wang Acked-by: Adam Radford Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa Signed-off-by: Stefan Bader --- drivers/scsi/3w-9xxx.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/scsi/3w-9xxx.c b/drivers/scsi/3w-9xxx.c index 00e7968a1d70..a1388842e17e 100644 --- a/drivers/scsi/3w-9xxx.c +++ b/drivers/scsi/3w-9xxx.c @@ -886,6 +886,11 @@ static int twa_chrdev_open(struct inode *inode, struct file *file) unsigned int minor_number; int retval = TW_IOCTL_ERROR_OS_ENODEV; + if (!capable(CAP_SYS_ADMIN)) { + retval = -EACCES; + goto out; + } + minor_number = iminor(inode); if (minor_number >= twa_device_extension_count) goto out; -- 2.39.2