Commit 1ab2de2b authored Aug 17, 2017 by Daniel Borkmann Committed by David S. Miller Aug 17, 2017

bpf: fix liveness propagation to parent in spilled stack slots



Using parent->regs[] when propagating REG_LIVE_READ for spilled regs
doesn't work since parent->regs[] denote the set of normal registers
but not spilled ones. Propagate to the correct regs.

Fixes: dc503a8a ("bpf/verifier: track liveness for pruning")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent fd07a62d

kernel/bpf/verifier.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -3460,7 +3460,7 @@ static bool do_propagate_liveness(const struct bpf_verifier_state *state,
	if (parent->spilled_regs[i].live & REG_LIVE_READ)		if (parent->spilled_regs[i].live & REG_LIVE_READ)
	continue;		continue;
	if (state->spilled_regs[i].live == REG_LIVE_READ) {		if (state->spilled_regs[i].live == REG_LIVE_READ) {
	parent->regs[i].live \|= REG_LIVE_READ;		parent->spilled_regs[i].live \|= REG_LIVE_READ;
	touched = true;		touched = true;
	}		}
	}		}