Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2017-12-03

The following pull-request contains BPF updates for your *net-next* tree.

The main changes are:

1) Addition of a software model for BPF offloads in order to ease
   testing code changes in that area and make semantics more clear.
   This is implemented in a new driver called netdevsim, which can
   later also be extended for other offloads. SR-IOV support is added
   as well to netdevsim. BPF kernel selftests for offloading are
   added so we can track basic functionality as well as exercising
   all corner cases around BPF offloading, from Jakub.

2) Today drivers have to drop the reference on BPF progs they hold
   due to XDP on device teardown themselves. Change this in order
   to make XDP handling inside the drivers less error prone, and
   move disabling XDP to the core instead, also from Jakub.

3) Misc set of BPF verifier improvements and cleanups as preparatory
   work for upcoming BPF-to-BPF calls. Among others, this set also
   improves liveness marking such that pruning can be slightly more
   effective. Register and stack liveness information is now included
   in the verifier log as well, from Alexei.

4) nfp JIT improvements in order to identify load/store sequences in
   the BPF prog e.g. coming from memcpy lowering and optimizing them
   through the NPU's command push pull (CPP) instruction, from Jiong.

5) Cleanups to test_cgrp2_attach2.c BPF sample code in oder to remove
   bpf_prog_attach() magic values and replacing them with actual proper
   attach flag instead, from David.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 42 insertions, 20 deletions

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index d4593571c404..7afa92e9b409 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -216,6 +216,17 @@ static const char * const reg_type_str[] = {
 	[PTR_TO_PACKET_END]	= "pkt_end",
 };
 
+static void print_liveness(struct bpf_verifier_env *env,
+			   enum bpf_reg_liveness live)
+{
+	if (live & (REG_LIVE_READ | REG_LIVE_WRITTEN))
+	    verbose(env, "_");
+	if (live & REG_LIVE_READ)
+		verbose(env, "r");
+	if (live & REG_LIVE_WRITTEN)
+		verbose(env, "w");
+}
+
 static void print_verifier_state(struct bpf_verifier_env *env,
 				 struct bpf_verifier_state *state)
 {
@@ -228,7 +239,9 @@ static void print_verifier_state(struct bpf_verifier_env *env,
 		t = reg->type;
 		if (t == NOT_INIT)
 			continue;
-		verbose(env, " R%d=%s", i, reg_type_str[t]);
+		verbose(env, " R%d", i);
+		print_liveness(env, reg->live);
+		verbose(env, "=%s", reg_type_str[t]);
 		if ((t == SCALAR_VALUE || t == PTR_TO_STACK) &&
 		    tnum_is_const(reg->var_off)) {
 			/* reg->off should be 0 for SCALAR_VALUE */
@@ -277,10 +290,13 @@ static void print_verifier_state(struct bpf_verifier_env *env,
 		}
 	}
 	for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
-		if (state->stack[i].slot_type[0] == STACK_SPILL)
-			verbose(env, " fp%d=%s",
-				-MAX_BPF_STACK + i * BPF_REG_SIZE,
+		if (state->stack[i].slot_type[0] == STACK_SPILL) {
+			verbose(env, " fp%d",
+				(-i - 1) * BPF_REG_SIZE);
+			print_liveness(env, state->stack[i].spilled_ptr.live);
+			verbose(env, "=%s",
 				reg_type_str[state->stack[i].spilled_ptr.type]);
+		}
 	}
 	verbose(env, "\n");
 }
@@ -568,8 +584,8 @@ static void mark_reg_unknown(struct bpf_verifier_env *env,
 {
 	if (WARN_ON(regno >= MAX_BPF_REG)) {
 		verbose(env, "mark_reg_unknown(regs, %u)\n", regno);
-		/* Something bad happened, let's kill all regs */
-		for (regno = 0; regno < MAX_BPF_REG; regno++)
+		/* Something bad happened, let's kill all regs except FP */
+		for (regno = 0; regno < BPF_REG_FP; regno++)
 			__mark_reg_not_init(regs + regno);
 		return;
 	}
@@ -587,8 +603,8 @@ static void mark_reg_not_init(struct bpf_verifier_env *env,
 {
 	if (WARN_ON(regno >= MAX_BPF_REG)) {
 		verbose(env, "mark_reg_not_init(regs, %u)\n", regno);
-		/* Something bad happened, let's kill all regs */
-		for (regno = 0; regno < MAX_BPF_REG; regno++)
+		/* Something bad happened, let's kill all regs except FP */
+		for (regno = 0; regno < BPF_REG_FP; regno++)
 			__mark_reg_not_init(regs + regno);
 		return;
 	}
@@ -779,6 +795,11 @@ static int check_stack_read(struct bpf_verifier_env *env,
 		if (value_regno >= 0) {
 			/* restore register state from stack */
 			state->regs[value_regno] = state->stack[spi].spilled_ptr;
+			/* mark reg as written since spilled pointer state likely
+			 * has its liveness marks cleared by is_state_visited()
+			 * which resets stack/reg liveness for state transitions
+			 */
+			state->regs[value_regno].live |= REG_LIVE_WRITTEN;
 			mark_stack_slot_read(state, spi);
 		}
 		return 0;
@@ -1244,9 +1265,9 @@ static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_ins
 }
 
 /* Does this register contain a constant zero? */
-static bool register_is_null(struct bpf_reg_state reg)
+static bool register_is_null(struct bpf_reg_state *reg)
 {
-	return reg.type == SCALAR_VALUE && tnum_equals_const(reg.var_off, 0);
+	return reg->type == SCALAR_VALUE && tnum_equals_const(reg->var_off, 0);
 }
 
 /* when register 'regno' is passed into function that will read 'access_size'
@@ -1259,31 +1280,31 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno,
 				int access_size, bool zero_size_allowed,
 				struct bpf_call_arg_meta *meta)
 {
+	struct bpf_reg_state *reg = cur_regs(env) + regno;
 	struct bpf_verifier_state *state = env->cur_state;
-	struct bpf_reg_state *regs = state->regs;
 	int off, i, slot, spi;
 
-	if (regs[regno].type != PTR_TO_STACK) {
+	if (reg->type != PTR_TO_STACK) {
 		/* Allow zero-byte read from NULL, regardless of pointer type */
 		if (zero_size_allowed && access_size == 0 &&
-		    register_is_null(regs[regno]))
+		    register_is_null(reg))
 			return 0;
 
 		verbose(env, "R%d type=%s expected=%s\n", regno,
-			reg_type_str[regs[regno].type],
+			reg_type_str[reg->type],
 			reg_type_str[PTR_TO_STACK]);
 		return -EACCES;
 	}
 
 	/* Only allow fixed-offset stack reads */
-	if (!tnum_is_const(regs[regno].var_off)) {
+	if (!tnum_is_const(reg->var_off)) {
 		char tn_buf[48];
 
-		tnum_strn(tn_buf, sizeof(tn_buf), regs[regno].var_off);
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
 		verbose(env, "invalid variable stack read R%d var_off=%s\n",
 			regno, tn_buf);
 	}
-	off = regs[regno].off + regs[regno].var_off.value;
+	off = reg->off + reg->var_off.value;
 	if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 ||
 	    access_size < 0 || (access_size == 0 && !zero_size_allowed)) {
 		verbose(env, "invalid stack type R%d off=%d access_size=%d\n",
@@ -1391,7 +1412,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
 		 * passed in as argument, it's a SCALAR_VALUE type. Final test
 		 * happens during stack boundary checking.
 		 */
-		if (register_is_null(*reg) &&
+		if (register_is_null(reg) &&
 		    arg_type == ARG_PTR_TO_MEM_OR_NULL)
 			/* final test in check_stack_boundary() */;
 		else if (!type_is_pkt_pointer(type) &&
@@ -2934,8 +2955,9 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
 	if (BPF_SRC(insn->code) == BPF_K &&
 	    (opcode == BPF_JEQ || opcode == BPF_JNE) &&
 	    dst_reg->type == SCALAR_VALUE &&
-	    tnum_equals_const(dst_reg->var_off, insn->imm)) {
-		if (opcode == BPF_JEQ) {
+	    tnum_is_const(dst_reg->var_off)) {
+		if ((opcode == BPF_JEQ && dst_reg->var_off.value == insn->imm) ||
+		    (opcode == BPF_JNE && dst_reg->var_off.value != insn->imm)) {
 			/* if (imm == imm) goto pc+off;
 			 * only follow the goto, ignore fall-through
 			 */