From: Joe Stringer <joe@wand.net.nz>
Date: Tue, 2 Oct 2018 13:35:29 -0700
Subject: bpf: Add iterator for spilled registers
Patch-mainline: v4.20-rc1
Git-commit: f3709f69b7c5cba6323cc03c29b64293b93be817
References: bsc#1109837
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: Joe Stringer <joe@wand.net.nz>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
include/linux/bpf_verifier.h | 11 +++++++++++
kernel/bpf/verifier.c | 16 +++++++---------
2 files changed, 18 insertions(+), 9 deletions(-)
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -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;
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2209,10 +2209,9 @@ static void __clear_all_pkt_pointers(str
if (reg_is_pkt_pointer_any(®s[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);
}
@@ -3360,10 +3359,9 @@ static void find_good_pkt_pointers(struc
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);
}
@@ -3608,7 +3606,7 @@ static void mark_map_regs(struct bpf_ver
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;
@@ -3617,8 +3615,8 @@ static void mark_map_regs(struct bpf_ver
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);
}