Commit f3709f69 authored by Joe Stringer's avatar Joe Stringer Committed by Daniel Borkmann
Browse files

bpf: Add iterator for spilled registers 



Add this iterator for spilled registers, it concentrates the details of
how to get the current frame's spilled registers into a single macro
while clarifying the intention of the code which is calling the macro.

Signed-off-by: default avatarJoe Stringer <joe@wand.net.nz>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 940656fb

include/linux/bpf_verifier.h

+11 −0
Original line number Diff line number Diff line
@@ -131,6 +131,17 @@ struct bpf_verifier_state { 
	u32 curframe;

};



#define bpf_get_spilled_reg(slot, frame)				\

	(((slot < frame->allocated_stack / BPF_REG_SIZE) &&		\

	  (frame->stack[slot].slot_type[0] == STACK_SPILL))		\

	 ? &frame->stack[slot].spilled_ptr : NULL)



/* Iterate over 'frame', setting 'reg' to either NULL or a spilled register. */

#define bpf_for_each_spilled_reg(iter, frame, reg)			\

	for (iter = 0, reg = bpf_get_spilled_reg(iter, frame);		\

	     iter < frame->allocated_stack / BPF_REG_SIZE;		\

	     iter++, reg = bpf_get_spilled_reg(iter, frame))



/* linked list of verifier states used to prune search */

struct bpf_verifier_state_list {

	struct bpf_verifier_state state;

kernel/bpf/verifier.c

+7 −9
Original line number Diff line number Diff line
@@ -2252,10 +2252,9 @@ static void __clear_all_pkt_pointers(struct bpf_verifier_env *env, 
		if (reg_is_pkt_pointer_any(&regs[i]))

			mark_reg_unknown(env, regs, i);



	for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {

		if (state->stack[i].slot_type[0] != STACK_SPILL)

	bpf_for_each_spilled_reg(i, state, reg) {

		if (!reg)

			continue;

		reg = &state->stack[i].spilled_ptr;

		if (reg_is_pkt_pointer_any(reg))

			__mark_reg_unknown(reg);

	}
@@ -3395,10 +3394,9 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *vstate, 


	for (j = 0; j <= vstate->curframe; j++) {

		state = vstate->frame[j];

		for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {

			if (state->stack[i].slot_type[0] != STACK_SPILL)

		bpf_for_each_spilled_reg(i, state, reg) {

			if (!reg)

				continue;

			reg = &state->stack[i].spilled_ptr;

			if (reg->type == type && reg->id == dst_reg->id)

				reg->range = max(reg->range, new_range);

		}
@@ -3643,7 +3641,7 @@ static void mark_map_regs(struct bpf_verifier_state *vstate, u32 regno, 
			  bool is_null)

{

	struct bpf_func_state *state = vstate->frame[vstate->curframe];

	struct bpf_reg_state *regs = state->regs;

	struct bpf_reg_state *reg, *regs = state->regs;

	u32 id = regs[regno].id;

	int i, j;
@@ -3652,8 +3650,8 @@ static void mark_map_regs(struct bpf_verifier_state *vstate, u32 regno, 


	for (j = 0; j <= vstate->curframe; j++) {

		state = vstate->frame[j];

		for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {

			if (state->stack[i].slot_type[0] != STACK_SPILL)

		bpf_for_each_spilled_reg(i, state, reg) {

			if (!reg)

				continue;

			mark_map_reg(&state->stack[i].spilled_ptr, 0, id, is_null);

		}

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