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

Daniel Borkmann says:

====================
pull-request: bpf 2021-02-10

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

We've added 5 non-merge commits during the last 8 day(s) which contain
a total of 3 files changed, 22 insertions(+), 21 deletions(-).

The main changes are:

1) Fix missed execution of kprobes BPF progs when kprobe is firing via
   int3, from Alexei Starovoitov.

2) Fix potential integer overflow in map max_entries for stackmap on
   32 bit archs, from Bui Quang Minh.

3) Fix a verifier pruning and a insn rewrite issue related to 32 bit ops,
   from Daniel Borkmann.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
c# Please enter a commit message to explain why this merge is necessary,

kernel/bpf/stackmap.c

@@ -115,6 +115,8 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
 
 	/* hash table size must be power of 2 */
 	n_buckets = roundup_pow_of_two(attr->max_entries);
+	if (!n_buckets)
+		return ERR_PTR(-E2BIG);
 
 	cost = n_buckets * sizeof(struct stack_map_bucket *) + sizeof(*smap);
 	cost += n_buckets * (value_size + sizeof(struct stack_map_bucket));

kernel/bpf/verifier.c

@@ -6877,7 +6877,7 @@ static int is_branch32_taken(struct bpf_reg_state *reg, u32 val, u8 opcode)
 	case BPF_JSGT:
 		if (reg->s32_min_value > sval)
 			return 1;
-		else if (reg->s32_max_value < sval)
+		else if (reg->s32_max_value <= sval)
 			return 0;
 		break;
 	case BPF_JLT:
@@ -6950,7 +6950,7 @@ static int is_branch64_taken(struct bpf_reg_state *reg, u64 val, u8 opcode)
 	case BPF_JSGT:
 		if (reg->smin_value > sval)
 			return 1;
-		else if (reg->smax_value < sval)
+		else if (reg->smax_value <= sval)
 			return 0;
 		break;
 	case BPF_JLT:
@@ -8590,7 +8590,11 @@ static bool range_within(struct bpf_reg_state *old,
 	return old->umin_value <= cur->umin_value &&
 	       old->umax_value >= cur->umax_value &&
 	       old->smin_value <= cur->smin_value &&
-	       old->smax_value >= cur->smax_value;
+	       old->smax_value >= cur->smax_value &&
+	       old->u32_min_value <= cur->u32_min_value &&
+	       old->u32_max_value >= cur->u32_max_value &&
+	       old->s32_min_value <= cur->s32_min_value &&
+	       old->s32_max_value >= cur->s32_max_value;
 }
 
 /* Maximum number of register states that can exist at once */
@@ -10999,30 +11003,28 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
 		    insn->code == (BPF_ALU | BPF_MOD | BPF_X) ||
 		    insn->code == (BPF_ALU | BPF_DIV | BPF_X)) {
 			bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;
-			struct bpf_insn mask_and_div[] = {
-				BPF_MOV32_REG(insn->src_reg, insn->src_reg),
+			bool isdiv = BPF_OP(insn->code) == BPF_DIV;
+			struct bpf_insn *patchlet;
+			struct bpf_insn chk_and_div[] = {
 				/* Rx div 0 -> 0 */
-				BPF_JMP_IMM(BPF_JNE, insn->src_reg, 0, 2),
+				BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
+					     BPF_JNE | BPF_K, insn->src_reg,
+					     0, 2, 0),
 				BPF_ALU32_REG(BPF_XOR, insn->dst_reg, insn->dst_reg),
 				BPF_JMP_IMM(BPF_JA, 0, 0, 1),
 				*insn,
 			};
-			struct bpf_insn mask_and_mod[] = {
-				BPF_MOV32_REG(insn->src_reg, insn->src_reg),
+			struct bpf_insn chk_and_mod[] = {
 				/* Rx mod 0 -> Rx */
-				BPF_JMP_IMM(BPF_JEQ, insn->src_reg, 0, 1),
+				BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
+					     BPF_JEQ | BPF_K, insn->src_reg,
+					     0, 1, 0),
 				*insn,
 			};
-			struct bpf_insn *patchlet;
 
-			if (insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) ||
-			    insn->code == (BPF_ALU | BPF_DIV | BPF_X)) {
-				patchlet = mask_and_div + (is64 ? 1 : 0);
-				cnt = ARRAY_SIZE(mask_and_div) - (is64 ? 1 : 0);
-			} else {
-				patchlet = mask_and_mod + (is64 ? 1 : 0);
-				cnt = ARRAY_SIZE(mask_and_mod) - (is64 ? 1 : 0);
-			}
+			patchlet = isdiv ? chk_and_div : chk_and_mod;
+			cnt = isdiv ? ARRAY_SIZE(chk_and_div) :
+				      ARRAY_SIZE(chk_and_mod);
 
 			new_prog = bpf_patch_insn_data(env, i + delta, patchlet, cnt);
 			if (!new_prog)

kernel/trace/bpf_trace.c

@@ -96,9 +96,6 @@ unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx)
 {
 	unsigned int ret;
 
-	if (in_nmi()) /* not supported yet */
-		return 1;
-
 	cant_sleep();
 
 	if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {