Messages in this thread | | | From | Ashwin H <> | Subject | RE: [PATCH v4.19.x] make 'user_access_begin()' do 'access_ok()' | Date | Wed, 13 May 2020 17:08:19 +0000 |
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> Ok, but what does that mean for us? > > You need to say why you are sending a patch, otherwise we will guess wrong.
In drivers/gpu/drm/i915/i915_gem_execbuffer.c, ioctl functions does user_access_begin() without doing access_ok(Checks if a user space pointer is valid) first. A local attacker can craft a malicious ioctl function call to overwrite arbitrary kernel memory, resulting in a Denial of Service or privilege escalation (CVE-2018-20669)
This patch makes sure that user_access_begin always does access_ok. user_access_begin has been modified to do access_ok internally.
Thanks, Ashwin
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