Messages in this thread | | | Date | Mon, 15 Oct 2018 21:39:28 -0700 (PDT) | Subject | Re: [PATCH] ethtool: fix a missing-check bug | From | David Miller <> |
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From: Wenwen Wang <wang6495@umn.edu> Date: Tue, 9 Oct 2018 08:15:38 -0500
> In ethtool_get_rxnfc(), the eth command 'cmd' is compared against > 'ETHTOOL_GRXFH' to see whether it is necessary to adjust the variable > 'info_size'. Then the whole structure of 'info' is copied from the > user-space buffer 'useraddr' with 'info_size' bytes. In the following > execution, 'info' may be copied again from the buffer 'useraddr' depending > on the 'cmd' and the 'info.flow_type'. However, after these two copies, > there is no check between 'cmd' and 'info.cmd'. In fact, 'cmd' is also > copied from the buffer 'useraddr' in dev_ethtool(), which is the caller > function of ethtool_get_rxnfc(). Given that 'useraddr' is in the user > space, a malicious user can race to change the eth command in the buffer > between these copies. By doing so, the attacker can supply inconsistent > data and cause undefined behavior because in the following execution 'info' > will be passed to ops->get_rxnfc(). > > This patch adds a necessary check on 'info.cmd' and 'cmd' to confirm that > they are still same after the two copies in ethtool_get_rxnfc(). Otherwise, > an error code EINVAL will be returned. > > Signed-off-by: Wenwen Wang <wang6495@umn.edu>
Applied.
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