Messages in this thread | | | Date | Fri, 05 Oct 2018 11:47:35 -0700 (PDT) | Subject | Re: [PATCH] net: cxgb3_main: fix a missing-check bug | From | David Miller <> |
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From: Wenwen Wang <wang6495@umn.edu> Date: Fri, 5 Oct 2018 08:48:27 -0500
> In cxgb_extension_ioctl(), the command of the ioctl is firstly copied from > the user-space buffer 'useraddr' to 'cmd' and checked through the > switch statement. If the command is not as expected, an error code > EOPNOTSUPP is returned. In the following execution, i.e., the cases of the > switch statement, the whole buffer of 'useraddr' is copied again to a > specific data structure, according to what kind of command is requested. > However, after the second copy, there is no re-check on the newly-copied > command. Given that the buffer 'useraddr' is in the user space, a malicious > user can race to change the command between the two copies. By doing so, > the attacker can supply malicious data to the kernel and cause undefined > behavior. > > This patch adds a re-check in each case of the switch statement if there is > a second copy in that case, to re-check whether the command obtained in the > second copy is the same as the one in the first copy. If not, an error code > EINVAL is returned. > > Signed-off-by: Wenwen Wang <wang6495@umn.edu>
Applied.
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