Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

Lots of easy overlapping changes in the confict
resolutions here.

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

1 files changed, 120 insertions, 25 deletions

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 967cacf286ea..1fd9667b29f1 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -157,7 +157,29 @@ struct bpf_verifier_stack_elem {
 #define BPF_COMPLEXITY_LIMIT_INSNS	131072
 #define BPF_COMPLEXITY_LIMIT_STACK	1024
 
-#define BPF_MAP_PTR_POISON ((void *)0xeB9F + POISON_POINTER_DELTA)
+#define BPF_MAP_PTR_UNPRIV	1UL
+#define BPF_MAP_PTR_POISON	((void *)((0xeB9FUL << 1) +	\
+					  POISON_POINTER_DELTA))
+#define BPF_MAP_PTR(X)		((struct bpf_map *)((X) & ~BPF_MAP_PTR_UNPRIV))
+
+static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data *aux)
+{
+	return BPF_MAP_PTR(aux->map_state) == BPF_MAP_PTR_POISON;
+}
+
+static bool bpf_map_ptr_unpriv(const struct bpf_insn_aux_data *aux)
+{
+	return aux->map_state & BPF_MAP_PTR_UNPRIV;
+}
+
+static void bpf_map_ptr_store(struct bpf_insn_aux_data *aux,
+			      const struct bpf_map *map, bool unpriv)
+{
+	BUILD_BUG_ON((unsigned long)BPF_MAP_PTR_POISON & BPF_MAP_PTR_UNPRIV);
+	unpriv |= bpf_map_ptr_unpriv(aux);
+	aux->map_state = (unsigned long)map |
+			 (unpriv ? BPF_MAP_PTR_UNPRIV : 0UL);
+}
 
 struct bpf_call_arg_meta {
 	struct bpf_map *map_ptr;
@@ -989,7 +1011,7 @@ static bool register_is_null(struct bpf_reg_state *reg)
  */
 static int check_stack_write(struct bpf_verifier_env *env,
 			     struct bpf_func_state *state, /* func where register points to */
-			     int off, int size, int value_regno)
+			     int off, int size, int value_regno, int insn_idx)
 {
 	struct bpf_func_state *cur; /* state of the current function */
 	int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err;
@@ -1028,8 +1050,33 @@ static int check_stack_write(struct bpf_verifier_env *env,
 		state->stack[spi].spilled_ptr = cur->regs[value_regno];
 		state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
 
-		for (i = 0; i < BPF_REG_SIZE; i++)
+		for (i = 0; i < BPF_REG_SIZE; i++) {
+			if (state->stack[spi].slot_type[i] == STACK_MISC &&
+			    !env->allow_ptr_leaks) {
+				int *poff = &env->insn_aux_data[insn_idx].sanitize_stack_off;
+				int soff = (-spi - 1) * BPF_REG_SIZE;
+
+				/* detected reuse of integer stack slot with a pointer
+				 * which means either llvm is reusing stack slot or
+				 * an attacker is trying to exploit CVE-2018-3639
+				 * (speculative store bypass)
+				 * Have to sanitize that slot with preemptive
+				 * store of zero.
+				 */
+				if (*poff && *poff != soff) {
+					/* disallow programs where single insn stores
+					 * into two different stack slots, since verifier
+					 * cannot sanitize them
+					 */
+					verbose(env,
+						"insn %d cannot access two stack slots fp%d and fp%d",
+						insn_idx, *poff, soff);
+					return -EINVAL;
+				}
+				*poff = soff;
+			}
 			state->stack[spi].slot_type[i] = STACK_SPILL;
+		}
 	} else {
 		u8 type = STACK_MISC;
 
@@ -1701,7 +1748,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
 
 		if (t == BPF_WRITE)
 			err = check_stack_write(env, state, off, size,
-						value_regno);
+						value_regno, insn_idx);
 		else
 			err = check_stack_read(env, state, off, size,
 					       value_regno);
@@ -2367,6 +2414,29 @@ static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,
 	__reg_bound_offset(ret_reg);
 }
 
+static int
+record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
+		int func_id, int insn_idx)
+{
+	struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx];
+
+	if (func_id != BPF_FUNC_tail_call &&
+	    func_id != BPF_FUNC_map_lookup_elem)
+		return 0;
+	if (meta->map_ptr == NULL) {
+		verbose(env, "kernel subsystem misconfigured verifier\n");
+		return -EINVAL;
+	}
+
+	if (!BPF_MAP_PTR(aux->map_state))
+		bpf_map_ptr_store(aux, meta->map_ptr,
+				  meta->map_ptr->unpriv_array);
+	else if (BPF_MAP_PTR(aux->map_state) != meta->map_ptr)
+		bpf_map_ptr_store(aux, BPF_MAP_PTR_POISON,
+				  meta->map_ptr->unpriv_array);
+	return 0;
+}
+
 static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn_idx)
 {
 	const struct bpf_func_proto *fn = NULL;
@@ -2421,13 +2491,6 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
 	err = check_func_arg(env, BPF_REG_2, fn->arg2_type, &meta);
 	if (err)
 		return err;
-	if (func_id == BPF_FUNC_tail_call) {
-		if (meta.map_ptr == NULL) {
-			verbose(env, "verifier bug\n");
-			return -EINVAL;
-		}
-		env->insn_aux_data[insn_idx].map_ptr = meta.map_ptr;
-	}
 	err = check_func_arg(env, BPF_REG_3, fn->arg3_type, &meta);
 	if (err)
 		return err;
@@ -2438,6 +2501,10 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
 	if (err)
 		return err;
 
+	err = record_func_map(env, &meta, func_id, insn_idx);
+	if (err)
+		return err;
+
 	/* Mark slots with STACK_MISC in case of raw mode, stack offset
 	 * is inferred from register state.
 	 */
@@ -2462,8 +2529,6 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
 	} else if (fn->ret_type == RET_VOID) {
 		regs[BPF_REG_0].type = NOT_INIT;
 	} else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL) {
-		struct bpf_insn_aux_data *insn_aux;
-
 		regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
 		/* There is no offset yet applied, variable or fixed */
 		mark_reg_known_zero(env, regs, BPF_REG_0);
@@ -2479,11 +2544,6 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
 		}
 		regs[BPF_REG_0].map_ptr = meta.map_ptr;
 		regs[BPF_REG_0].id = ++env->id_gen;
-		insn_aux = &env->insn_aux_data[insn_idx];
-		if (!insn_aux->map_ptr)
-			insn_aux->map_ptr = meta.map_ptr;
-		else if (insn_aux->map_ptr != meta.map_ptr)
-			insn_aux->map_ptr = BPF_MAP_PTR_POISON;
 	} else {
 		verbose(env, "unknown return type %d of func %s#%d\n",
 			fn->ret_type, func_id_name(func_id), func_id);
@@ -5245,6 +5305,34 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
 		else
 			continue;
 
+		if (type == BPF_WRITE &&
+		    env->insn_aux_data[i + delta].sanitize_stack_off) {
+			struct bpf_insn patch[] = {
+				/* Sanitize suspicious stack slot with zero.
+				 * There are no memory dependencies for this store,
+				 * since it's only using frame pointer and immediate
+				 * constant of zero
+				 */
+				BPF_ST_MEM(BPF_DW, BPF_REG_FP,
+					   env->insn_aux_data[i + delta].sanitize_stack_off,
+					   0),
+				/* the original STX instruction will immediately
+				 * overwrite the same stack slot with appropriate value
+				 */
+				*insn,
+			};
+
+			cnt = ARRAY_SIZE(patch);
+			new_prog = bpf_patch_insn_data(env, i + delta, patch, cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta    += cnt - 1;
+			env->prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
 		if (env->insn_aux_data[i + delta].ptr_type != PTR_TO_CTX)
 			continue;
 
@@ -5498,6 +5586,7 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
 	struct bpf_insn *insn = prog->insnsi;
 	const struct bpf_func_proto *fn;
 	const int insn_cnt = prog->len;
+	struct bpf_insn_aux_data *aux;
 	struct bpf_insn insn_buf[16];
 	struct bpf_prog *new_prog;
 	struct bpf_map *map_ptr;
@@ -5591,19 +5680,22 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
 			insn->imm = 0;
 			insn->code = BPF_JMP | BPF_TAIL_CALL;
 
+			aux = &env->insn_aux_data[i + delta];
+			if (!bpf_map_ptr_unpriv(aux))
+				continue;
+
 			/* instead of changing every JIT dealing with tail_call
 			 * emit two extra insns:
 			 * if (index >= max_entries) goto out;
 			 * index &= array->index_mask;
 			 * to avoid out-of-bounds cpu speculation
 			 */
-			map_ptr = env->insn_aux_data[i + delta].map_ptr;
-			if (map_ptr == BPF_MAP_PTR_POISON) {
+			if (bpf_map_ptr_poisoned(aux)) {
 				verbose(env, "tail_call abusing map_ptr\n");
 				return -EINVAL;
 			}
-			if (!map_ptr->unpriv_array)
-				continue;
+
+			map_ptr = BPF_MAP_PTR(aux->map_state);
 			insn_buf[0] = BPF_JMP_IMM(BPF_JGE, BPF_REG_3,
 						  map_ptr->max_entries, 2);
 			insn_buf[1] = BPF_ALU32_IMM(BPF_AND, BPF_REG_3,
@@ -5627,9 +5719,12 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
 		 */
 		if (prog->jit_requested && BITS_PER_LONG == 64 &&
 		    insn->imm == BPF_FUNC_map_lookup_elem) {
-			map_ptr = env->insn_aux_data[i + delta].map_ptr;
-			if (map_ptr == BPF_MAP_PTR_POISON ||
-			    !map_ptr->ops->map_gen_lookup)
+			aux = &env->insn_aux_data[i + delta];
+			if (bpf_map_ptr_poisoned(aux))
+				goto patch_call_imm;
+
+			map_ptr = BPF_MAP_PTR(aux->map_state);
+			if (!map_ptr->ops->map_gen_lookup)
 				goto patch_call_imm;
 
 			cnt = map_ptr->ops->map_gen_lookup(map_ptr, insn_buf);