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author | David S. Miller <davem@davemloft.net> | 2010-11-10 10:38:24 -0800 |
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committer | David S. Miller <davem@davemloft.net> | 2010-11-10 10:38:24 -0800 |
commit | 57fe93b374a6b8711995c2d466c502af9f3a08bb (patch) | |
tree | 12648abf4c941275e5a12a8416e8fa6a92276753 /net/packet/af_packet.c | |
parent | fe10ae53384e48c51996941b7720ee16995cbcb7 (diff) |
filter: make sure filters dont read uninitialized memory
There is a possibility malicious users can get limited information about
uninitialized stack mem array. Even if sk_run_filter() result is bound
to packet length (0 .. 65535), we could imagine this can be used by
hostile user.
Initializing mem[] array, like Dan Rosenberg suggested in his patch is
expensive since most filters dont even use this array.
Its hard to make the filter validation in sk_chk_filter(), because of
the jumps. This might be done later.
In this patch, I use a bitmap (a single long var) so that only filters
using mem[] loads/stores pay the price of added security checks.
For other filters, additional cost is a single instruction.
[ Since we access fentry->k a lot now, cache it in a local variable
and mark filter entry pointer as const. -DaveM ]
Reported-by: Dan Rosenberg <drosenberg@vsecurity.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/packet/af_packet.c')
0 files changed, 0 insertions, 0 deletions