LKML Archive on
help / color / mirror / Atom feed
From: Wenwen Wang <>
To: Wenwen Wang <>
Cc: Kangjie Lu <>, Adam Radford <>,
	"James E.J. Bottomley" <>,
	"Martin K. Petersen" <>,, (open list)
Subject: [PATCH] scsi: 3ware: fix a missing-check bug
Date: Sun,  6 May 2018 00:50:47 -0500	[thread overview]
Message-ID: <> (raw)

In twl_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 the buffer size obtained in the second copy. An error
code -EINVAL will be returned if it is not same as the original one in the
first copy.

Signed-off-by: Wenwen Wang <>
 drivers/scsi/3w-sas.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/scsi/3w-sas.c b/drivers/scsi/3w-sas.c
index cf9f2a0..ea41969 100644
--- a/drivers/scsi/3w-sas.c
+++ b/drivers/scsi/3w-sas.c
@@ -757,6 +757,11 @@ static long twl_chrdev_ioctl(struct file *file, unsigned int cmd, unsigned long
 	/* Now copy down the entire ioctl */
 	if (copy_from_user(tw_ioctl, argp, driver_command.buffer_length + sizeof(TW_Ioctl_Buf_Apache) - 1))
 		goto out3;
+	if (tw_ioctl->driver_command.buffer_length !=
+	    driver_command.buffer_length) {
+		retval = -EINVAL;
+		goto out3;
+	}
 	/* See which ioctl we are doing */
 	switch (cmd) {

             reply	other threads:[~2018-05-06  5:51 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-06  5:50 Wenwen Wang [this message]
2018-05-08  0:20 ` adam radford

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:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \
    --subject='Re: [PATCH] scsi: 3ware: fix a missing-check bug' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

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 NNTP newsgroup(s).