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

Daniel Borkmann says:

====================
pull-request: bpf 2018-02-28

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

The main changes are:

1) Add schedule points and reduce the number of loop iterations
the test_bpf kernel module is performing in order to not hog
the CPU for too long, from Eric.

2) Fix an out of bounds access in tail calls in the ppc64 BPF
JIT compiler, from Daniel.

3) Fix a crash on arm64 on unaligned BPF xadd operations that
could be triggered via interpreter and JIT, from Daniel.

Please not that once you merge net into net-next at some point, there
is a minor merge conflict in test_verifier.c since test cases had
been added at the end in both trees. Resolution is trivial: keep all
the test cases from both trees.
====================

Signed-off-by: David S. Miller <[e-mail]>

arch/powerpc/net/bpf_jit_comp64.c

···
 	 *   goto out;
 	 */
 	PPC_LWZ(b2p[TMP_REG_1], b2p_bpf_array, offsetof(struct bpf_array, map.max_entries));
+	PPC_RLWINM(b2p_index, b2p_index, 0, 0, 31);
 	PPC_CMPLW(b2p_index, b2p[TMP_REG_1]);
 	PPC_BCC(COND_GE, out);
 

kernel/bpf/verifier.c

···
 	return reg->type == PTR_TO_CTX;
 }
 
+static bool is_pkt_reg(struct bpf_verifier_env *env, int regno)
+{
+	const struct bpf_reg_state *reg = cur_regs(env) + regno;
+
+	return type_is_pkt_pointer(reg->type);
+}
+
 static int check_pkt_ptr_alignment(struct bpf_verifier_env *env,
 				   const struct bpf_reg_state *reg,
 				   int off, int size, bool strict)
···
 }
 
 static int check_ptr_alignment(struct bpf_verifier_env *env,
-			       const struct bpf_reg_state *reg,
-			       int off, int size)
+			       const struct bpf_reg_state *reg, int off,
+			       int size, bool strict_alignment_once)
 {
-	bool strict = env->strict_alignment;
+	bool strict = env->strict_alignment || strict_alignment_once;
 	const char *pointer_desc = "";
 
 	switch (reg->type) {
···
  * if t==write && value_regno==-1, some unknown value is stored into memory
  * if t==read && value_regno==-1, don't care what we read from memory
  */
-static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno, int off,
-			    int bpf_size, enum bpf_access_type t,
-			    int value_regno)
+static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno,
+			    int off, int bpf_size, enum bpf_access_type t,
+			    int value_regno, bool strict_alignment_once)
 {
 	struct bpf_reg_state *regs = cur_regs(env);
 	struct bpf_reg_state *reg = regs + regno;
···
 		return size;
 
 	/* alignment checks will add in reg->off themselves */
-	err = check_ptr_alignment(env, reg, off, size);
+	err = check_ptr_alignment(env, reg, off, size, strict_alignment_once);
 	if (err)
 		return err;
 
···
 		return -EACCES;
 	}
 
-	if (is_ctx_reg(env, insn->dst_reg)) {
-		verbose(env, "BPF_XADD stores into R%d context is not allowed\n",
-			insn->dst_reg);
+	if (is_ctx_reg(env, insn->dst_reg) ||
+	    is_pkt_reg(env, insn->dst_reg)) {
+		verbose(env, "BPF_XADD stores into R%d %s is not allowed\n",
+			insn->dst_reg, is_ctx_reg(env, insn->dst_reg) ?
+			"context" : "packet");
 		return -EACCES;
 	}
 
 	/* check whether atomic_add can read the memory */
 	err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
-			       BPF_SIZE(insn->code), BPF_READ, -1);
+			       BPF_SIZE(insn->code), BPF_READ, -1, true);
 	if (err)
 		return err;
 
 	/* check whether atomic_add can write into the same memory */
 	return check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
-				BPF_SIZE(insn->code), BPF_WRITE, -1);
+				BPF_SIZE(insn->code), BPF_WRITE, -1, true);
 }
 
 /* when register 'regno' is passed into function that will read 'access_size'
···
 	 * is inferred from register state.
 	 */
 	for (i = 0; i < meta.access_size; i++) {
-		err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B, BPF_WRITE, -1);
+		err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B,
+				       BPF_WRITE, -1, false);
 		if (err)
 			return err;
 	}
···
 			 */
 			err = check_mem_access(env, insn_idx, insn->src_reg, insn->off,
 					       BPF_SIZE(insn->code), BPF_READ,
-					       insn->dst_reg);
+					       insn->dst_reg, false);
 			if (err)
 				return err;
 
···
 			/* check that memory (dst_reg + off) is writeable */
 			err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
 					       BPF_SIZE(insn->code), BPF_WRITE,
-					       insn->src_reg);
+					       insn->src_reg, false);
 			if (err)
 				return err;
 
···
 			/* check that memory (dst_reg + off) is writeable */
 			err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
 					       BPF_SIZE(insn->code), BPF_WRITE,
-					       -1);
+					       -1, false);
 			if (err)
 				return err;
 

lib/test_bpf.c

···
 #include <linux/if_vlan.h>
 #include <linux/random.h>
 #include <linux/highmem.h>
+#include <linux/sched.h>
 
 /* General test specific settings */
 #define MAX_SUBTESTS	3
-#define MAX_TESTRUNS	10000
+#define MAX_TESTRUNS	1000
 #define MAX_DATA	128
 #define MAX_INSNS	512
 #define MAX_K		0xffffFFFF
···
 		struct bpf_prog *fp;
 		int err;
 
+		cond_resched();
 		if (exclude_test(i))
 			continue;
 

tools/testing/selftests/bpf/test_verifier.c

···
 		.result = REJECT,
 		.prog_type = BPF_PROG_TYPE_TRACEPOINT,
 	},
+	{
+		"xadd/w check unaligned stack",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
+			BPF_STX_XADD(BPF_W, BPF_REG_10, BPF_REG_0, -7),
+			BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),
+			BPF_EXIT_INSN(),
+		},
+		.result = REJECT,
+		.errstr = "misaligned stack access off",
+		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+	},
+	{
+		"xadd/w check unaligned map",
+		.insns = {
+			BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+			BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+			BPF_LD_MAP_FD(BPF_REG_1, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_map_lookup_elem),
+			BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+			BPF_EXIT_INSN(),
+			BPF_MOV64_IMM(BPF_REG_1, 1),
+			BPF_STX_XADD(BPF_W, BPF_REG_0, BPF_REG_1, 3),
+			BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 3),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_map1 = { 3 },
+		.result = REJECT,
+		.errstr = "misaligned value access off",
+		.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+	},
+	{
+		"xadd/w check unaligned pkt",
+		.insns = {
+			BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+				    offsetof(struct xdp_md, data)),
+			BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
+				    offsetof(struct xdp_md, data_end)),
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+			BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+			BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_3, 2),
+			BPF_MOV64_IMM(BPF_REG_0, 99),
+			BPF_JMP_IMM(BPF_JA, 0, 0, 6),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_ST_MEM(BPF_W, BPF_REG_2, 0, 0),
+			BPF_ST_MEM(BPF_W, BPF_REG_2, 3, 0),
+			BPF_STX_XADD(BPF_W, BPF_REG_2, BPF_REG_0, 1),
+			BPF_STX_XADD(BPF_W, BPF_REG_2, BPF_REG_0, 2),
+			BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 1),
+			BPF_EXIT_INSN(),
+		},
+		.result = REJECT,
+		.errstr = "BPF_XADD stores into R2 packet",
+		.prog_type = BPF_PROG_TYPE_XDP,
+	},
 };
 
 static int probe_filter_length(const struct bpf_insn *fp)