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net/packet: check length in getsockopt() called with PACKET_HDRLEN
authorAlexander Potapenko <glider@google.com>
Tue, 25 Apr 2017 16:51:46 +0000 (18:51 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 8 Oct 2017 08:14:18 +0000 (10:14 +0200)
commitfa63895f47c9253a0305a5d0862e98ab6f11e718
treeea7d82fce77c6190a6fdab11cecb599902133f3e
parentb9ff317b5cd4a8f7ca13934af679e129c3f1d2ce
net/packet: check length in getsockopt() called with PACKET_HDRLEN

[ Upstream commit fd2c83b35752f0a8236b976978ad4658df14a59f ]

In the case getsockopt() is called with PACKET_HDRLEN and optlen < 4
|val| remains uninitialized and the syscall may behave differently
depending on its value, and even copy garbage to userspace on certain
architectures. To fix this we now return -EINVAL if optlen is too small.

This bug has been detected with KMSAN.

Signed-off-by: Alexander Potapenko <glider@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/packet/af_packet.c