tree 1ac843fc3e185a7e2328a832b1d929f199205bb3
parent 2066499780e1455c43833b5b34858124047331ff
author Florian Westphal <fw@strlen.de> 1459513048 +0200
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1466788703 -0700

netfilter: x_tables: check for bogus target offset

commit ce683e5f9d045e5d67d1312a42b359cb2ab2a13c upstream.

We're currently asserting that targetoff + targetsize <= nextoff.

Extend it to also check that targetoff is >= sizeof(xt_entry).
Since this is generic code, add an argument pointing to the start of the
match/target, we can then derive the base structure size from the delta.

We also need the e->elems pointer in a followup change to validate matches.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>