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authorJiong Wang <jiong.wang@netronome.com>2018-12-15 09:34:40 +0100
committerAlexei Starovoitov <ast@kernel.org>2018-12-18 23:45:01 +0100
commit0bae2d4d62d523f06ff1a8e88ce38b45400acd28 (patch)
treebf6f6180c0843475a553345c96f4e4c00c2272ca /net
parentbpf: support raw tracepoints in modules (diff)
downloadlinux-0bae2d4d62d523f06ff1a8e88ce38b45400acd28.tar.xz
linux-0bae2d4d62d523f06ff1a8e88ce38b45400acd28.zip
bpf: correct slot_type marking logic to allow more stack slot sharing
Verifier is supposed to support sharing stack slot allocated to ptr with SCALAR_VALUE for privileged program. However this doesn't happen for some cases. The reason is verifier is not clearing slot_type STACK_SPILL for all bytes, it only clears part of them, while verifier is using: slot_type[0] == STACK_SPILL as a convention to check one slot is ptr type. So, the consequence of partial clearing slot_type is verifier could treat a partially overridden ptr slot, which should now be a SCALAR_VALUE slot, still as ptr slot, and rejects some valid programs. Before this patch, test_xdp_noinline.o under bpf selftests, bpf_lxc.o and bpf_netdev.o under Cilium bpf repo, when built with -mattr=+alu32 are rejected due to this issue. After this patch, they all accepted. There is no processed insn number change before and after this patch on Cilium bpf programs. Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Jiong Wang <jiong.wang@netronome.com> Reviewed-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'net')
0 files changed, 0 insertions, 0 deletions