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authorDaniel Borkmann <daniel@iogearbox.net>2017-12-14 21:07:25 +0100
committerAlexei Starovoitov <ast@kernel.org>2017-12-15 09:19:35 -0800
commit04514d13222f2c4c91adf0ecb21004cec3388795 (patch)
tree18f3909ec2918ce8b46cac6ed9d76013dc603022 /arch/sparc
parent87338c8e2cbb317b5f757e6172f94e2e3799cd20 (diff)
bpf: guarantee r1 to be ctx in case of bpf_helper_changes_pkt_data
Some JITs don't cache skb context on stack in prologue, so when LD_ABS/IND is used and helper calls yield bpf_helper_changes_pkt_data() as true, then they temporarily save/restore skb pointer. However, the assumption that skb always has to be in r1 is a bit of a gamble. Right now it turned out to be true for all helpers listed in bpf_helper_changes_pkt_data(), but lets enforce that from verifier side, so that we make this a guarantee and bail out if the func proto is misconfigured in future helpers. In case of BPF helper calls from cBPF, bpf_helper_changes_pkt_data() is completely unrelevant here (since cBPF is context read-only) and therefore always false. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'arch/sparc')
0 files changed, 0 insertions, 0 deletions

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