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Commit e37d05a5 authored by David S. Miller's avatar David S. Miller
Browse files


Alexei Starovoitov says:

====================
pull-request: bpf 2018-12-05

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

The main changes are:

1) fix bpf uapi pointers for 32-bit architectures, from Daniel.

2) improve verifer ability to handle progs with a lot of branches, from Alexei.

3) strict btf checks, from Yonghong.

4) bpf_sk_lookup api cleanup, from Joe.

5) other misc fixes
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 22f6bbb7 a92a72a2
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+66 −0
Original line number Diff line number Diff line
@@ -891,6 +891,55 @@ static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
	return 0;
}

/* Fix the branch target addresses for subprog calls */
static int bpf_jit_fixup_subprog_calls(struct bpf_prog *fp, u32 *image,
				       struct codegen_context *ctx, u32 *addrs)
{
	const struct bpf_insn *insn = fp->insnsi;
	bool func_addr_fixed;
	u64 func_addr;
	u32 tmp_idx;
	int i, ret;

	for (i = 0; i < fp->len; i++) {
		/*
		 * During the extra pass, only the branch target addresses for
		 * the subprog calls need to be fixed. All other instructions
		 * can left untouched.
		 *
		 * The JITed image length does not change because we already
		 * ensure that the JITed instruction sequence for these calls
		 * are of fixed length by padding them with NOPs.
		 */
		if (insn[i].code == (BPF_JMP | BPF_CALL) &&
		    insn[i].src_reg == BPF_PSEUDO_CALL) {
			ret = bpf_jit_get_func_addr(fp, &insn[i], true,
						    &func_addr,
						    &func_addr_fixed);
			if (ret < 0)
				return ret;

			/*
			 * Save ctx->idx as this would currently point to the
			 * end of the JITed image and set it to the offset of
			 * the instruction sequence corresponding to the
			 * subprog call temporarily.
			 */
			tmp_idx = ctx->idx;
			ctx->idx = addrs[i] / 4;
			bpf_jit_emit_func_call_rel(image, ctx, func_addr);

			/*
			 * Restore ctx->idx here. This is safe as the length
			 * of the JITed sequence remains unchanged.
			 */
			ctx->idx = tmp_idx;
		}
	}

	return 0;
}

struct powerpc64_jit_data {
	struct bpf_binary_header *header;
	u32 *addrs;
@@ -989,6 +1038,22 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
skip_init_ctx:
	code_base = (u32 *)(image + FUNCTION_DESCR_SIZE);

	if (extra_pass) {
		/*
		 * Do not touch the prologue and epilogue as they will remain
		 * unchanged. Only fix the branch target address for subprog
		 * calls in the body.
		 *
		 * This does not change the offsets and lengths of the subprog
		 * call instruction sequences and hence, the size of the JITed
		 * image as well.
		 */
		bpf_jit_fixup_subprog_calls(fp, code_base, &cgctx, addrs);

		/* There is no need to perform the usual passes. */
		goto skip_codegen_passes;
	}

	/* Code generation passes 1-2 */
	for (pass = 1; pass < 3; pass++) {
		/* Now build the prologue, body code & epilogue for real. */
@@ -1002,6 +1067,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
				proglen - (cgctx.idx * 4), cgctx.seen);
	}

skip_codegen_passes:
	if (bpf_jit_enable > 1)
		/*
		 * Note that we output the base address of the code_base
+7 −0
Original line number Diff line number Diff line
@@ -449,6 +449,13 @@ struct sock_reuseport;
	offsetof(TYPE, MEMBER) ... offsetofend(TYPE, MEMBER) - 1
#define bpf_ctx_range_till(TYPE, MEMBER1, MEMBER2)				\
	offsetof(TYPE, MEMBER1) ... offsetofend(TYPE, MEMBER2) - 1
#if BITS_PER_LONG == 64
# define bpf_ctx_range_ptr(TYPE, MEMBER)					\
	offsetof(TYPE, MEMBER) ... offsetofend(TYPE, MEMBER) - 1
#else
# define bpf_ctx_range_ptr(TYPE, MEMBER)					\
	offsetof(TYPE, MEMBER) ... offsetof(TYPE, MEMBER) + 8 - 1
#endif /* BITS_PER_LONG == 64 */

#define bpf_target_off(TYPE, MEMBER, SIZE, PTR_SIZE)				\
	({									\
+37 −19
Original line number Diff line number Diff line
@@ -2170,7 +2170,7 @@ union bpf_attr {
 *	Return
 *		0 on success, or a negative error in case of failure.
 *
 * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u32 netns, u64 flags)
 * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
 *	Description
 *		Look for TCP socket matching *tuple*, optionally in a child
 *		network namespace *netns*. The return value must be checked,
@@ -2187,12 +2187,14 @@ union bpf_attr {
 *		**sizeof**\ (*tuple*\ **->ipv6**)
 *			Look for an IPv6 socket.
 *
 *		If the *netns* is zero, then the socket lookup table in the
 *		netns associated with the *ctx* will be used. For the TC hooks,
 *		this in the netns of the device in the skb. For socket hooks,
 *		this in the netns of the socket. If *netns* is non-zero, then
 *		it specifies the ID of the netns relative to the netns
 *		associated with the *ctx*.
 *		If the *netns* is a negative signed 32-bit integer, then the
 *		socket lookup table in the netns associated with the *ctx* will
 *		will be used. For the TC hooks, this is the netns of the device
 *		in the skb. For socket hooks, this is the netns of the socket.
 *		If *netns* is any other signed 32-bit value greater than or
 *		equal to zero then it specifies the ID of the netns relative to
 *		the netns associated with the *ctx*. *netns* values beyond the
 *		range of 32-bit integers are reserved for future use.
 *
 *		All values for *flags* are reserved for future usage, and must
 *		be left at zero.
@@ -2201,8 +2203,10 @@ union bpf_attr {
 *		**CONFIG_NET** configuration option.
 *	Return
 *		Pointer to *struct bpf_sock*, or NULL in case of failure.
 *		For sockets with reuseport option, the *struct bpf_sock*
 *		result is from reuse->socks[] using the hash of the tuple.
 *
 * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u32 netns, u64 flags)
 * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
 *	Description
 *		Look for UDP socket matching *tuple*, optionally in a child
 *		network namespace *netns*. The return value must be checked,
@@ -2219,12 +2223,14 @@ union bpf_attr {
 *		**sizeof**\ (*tuple*\ **->ipv6**)
 *			Look for an IPv6 socket.
 *
 *		If the *netns* is zero, then the socket lookup table in the
 *		netns associated with the *ctx* will be used. For the TC hooks,
 *		this in the netns of the device in the skb. For socket hooks,
 *		this in the netns of the socket. If *netns* is non-zero, then
 *		it specifies the ID of the netns relative to the netns
 *		associated with the *ctx*.
 *		If the *netns* is a negative signed 32-bit integer, then the
 *		socket lookup table in the netns associated with the *ctx* will
 *		will be used. For the TC hooks, this is the netns of the device
 *		in the skb. For socket hooks, this is the netns of the socket.
 *		If *netns* is any other signed 32-bit value greater than or
 *		equal to zero then it specifies the ID of the netns relative to
 *		the netns associated with the *ctx*. *netns* values beyond the
 *		range of 32-bit integers are reserved for future use.
 *
 *		All values for *flags* are reserved for future usage, and must
 *		be left at zero.
@@ -2233,6 +2239,8 @@ union bpf_attr {
 *		**CONFIG_NET** configuration option.
 *	Return
 *		Pointer to *struct bpf_sock*, or NULL in case of failure.
 *		For sockets with reuseport option, the *struct bpf_sock*
 *		result is from reuse->socks[] using the hash of the tuple.
 *
 * int bpf_sk_release(struct bpf_sock *sk)
 *	Description
@@ -2405,6 +2413,9 @@ enum bpf_func_id {
/* BPF_FUNC_perf_event_output for sk_buff input context. */
#define BPF_F_CTXLEN_MASK		(0xfffffULL << 32)

/* Current network namespace */
#define BPF_F_CURRENT_NETNS		(-1L)

/* Mode for BPF_FUNC_skb_adjust_room helper. */
enum bpf_adj_room_mode {
	BPF_ADJ_ROOM_NET,
@@ -2422,6 +2433,12 @@ enum bpf_lwt_encap_mode {
	BPF_LWT_ENCAP_SEG6_INLINE
};

#define __bpf_md_ptr(type, name)	\
union {					\
	type name;			\
	__u64 :64;			\
} __attribute__((aligned(8)))

/* user accessible mirror of in-kernel sk_buff.
 * new fields can only be added to the end of this structure
 */
@@ -2456,7 +2473,7 @@ struct __sk_buff {
	/* ... here. */

	__u32 data_meta;
	struct bpf_flow_keys *flow_keys;
	__bpf_md_ptr(struct bpf_flow_keys *, flow_keys);
};

struct bpf_tunnel_key {
@@ -2572,8 +2589,8 @@ enum sk_action {
 * be added to the end of this structure
 */
struct sk_msg_md {
	void *data;
	void *data_end;
	__bpf_md_ptr(void *, data);
	__bpf_md_ptr(void *, data_end);

	__u32 family;
	__u32 remote_ip4;	/* Stored in network byte order */
@@ -2589,8 +2606,9 @@ struct sk_reuseport_md {
	 * Start of directly accessible data. It begins from
	 * the tcp/udp header.
	 */
	void *data;
	void *data_end;		/* End of directly accessible data */
	__bpf_md_ptr(void *, data);
	/* End of directly accessible data */
	__bpf_md_ptr(void *, data_end);
	/*
	 * Total length of packet (starting from the tcp/udp header).
	 * Note that the directly accessible bytes (data_end - data)
+82 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@
#include <uapi/linux/types.h>
#include <linux/seq_file.h>
#include <linux/compiler.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/anon_inodes.h>
@@ -426,6 +427,30 @@ static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
		offset < btf->hdr.str_len;
}

/* Only C-style identifier is permitted. This can be relaxed if
 * necessary.
 */
static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
{
	/* offset must be valid */
	const char *src = &btf->strings[offset];
	const char *src_limit;

	if (!isalpha(*src) && *src != '_')
		return false;

	/* set a limit on identifier length */
	src_limit = src + KSYM_NAME_LEN;
	src++;
	while (*src && src < src_limit) {
		if (!isalnum(*src) && *src != '_')
			return false;
		src++;
	}

	return !*src;
}

static const char *btf_name_by_offset(const struct btf *btf, u32 offset)
{
	if (!offset)
@@ -1143,6 +1168,22 @@ static int btf_ref_type_check_meta(struct btf_verifier_env *env,
		return -EINVAL;
	}

	/* typedef type must have a valid name, and other ref types,
	 * volatile, const, restrict, should have a null name.
	 */
	if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
		if (!t->name_off ||
		    !btf_name_valid_identifier(env->btf, t->name_off)) {
			btf_verifier_log_type(env, t, "Invalid name");
			return -EINVAL;
		}
	} else {
		if (t->name_off) {
			btf_verifier_log_type(env, t, "Invalid name");
			return -EINVAL;
		}
	}

	btf_verifier_log_type(env, t, NULL);

	return 0;
@@ -1300,6 +1341,13 @@ static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
		return -EINVAL;
	}

	/* fwd type must have a valid name */
	if (!t->name_off ||
	    !btf_name_valid_identifier(env->btf, t->name_off)) {
		btf_verifier_log_type(env, t, "Invalid name");
		return -EINVAL;
	}

	btf_verifier_log_type(env, t, NULL);

	return 0;
@@ -1356,6 +1404,12 @@ static s32 btf_array_check_meta(struct btf_verifier_env *env,
		return -EINVAL;
	}

	/* array type should not have a name */
	if (t->name_off) {
		btf_verifier_log_type(env, t, "Invalid name");
		return -EINVAL;
	}

	if (btf_type_vlen(t)) {
		btf_verifier_log_type(env, t, "vlen != 0");
		return -EINVAL;
@@ -1532,6 +1586,13 @@ static s32 btf_struct_check_meta(struct btf_verifier_env *env,
		return -EINVAL;
	}

	/* struct type either no name or a valid one */
	if (t->name_off &&
	    !btf_name_valid_identifier(env->btf, t->name_off)) {
		btf_verifier_log_type(env, t, "Invalid name");
		return -EINVAL;
	}

	btf_verifier_log_type(env, t, NULL);

	last_offset = 0;
@@ -1543,6 +1604,12 @@ static s32 btf_struct_check_meta(struct btf_verifier_env *env,
			return -EINVAL;
		}

		/* struct member either no name or a valid one */
		if (member->name_off &&
		    !btf_name_valid_identifier(btf, member->name_off)) {
			btf_verifier_log_member(env, t, member, "Invalid name");
			return -EINVAL;
		}
		/* A member cannot be in type void */
		if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
			btf_verifier_log_member(env, t, member,
@@ -1730,6 +1797,13 @@ static s32 btf_enum_check_meta(struct btf_verifier_env *env,
		return -EINVAL;
	}

	/* enum type either no name or a valid one */
	if (t->name_off &&
	    !btf_name_valid_identifier(env->btf, t->name_off)) {
		btf_verifier_log_type(env, t, "Invalid name");
		return -EINVAL;
	}

	btf_verifier_log_type(env, t, NULL);

	for (i = 0; i < nr_enums; i++) {
@@ -1739,6 +1813,14 @@ static s32 btf_enum_check_meta(struct btf_verifier_env *env,
			return -EINVAL;
		}

		/* enum member must have a valid name */
		if (!enums[i].name_off ||
		    !btf_name_valid_identifier(btf, enums[i].name_off)) {
			btf_verifier_log_type(env, t, "Invalid name");
			return -EINVAL;
		}


		btf_verifier_log(env, "\t%s val=%d\n",
				 btf_name_by_offset(btf, enums[i].name_off),
				 enums[i].val);
+89 −14
Original line number Diff line number Diff line
@@ -175,6 +175,7 @@ struct bpf_verifier_stack_elem {

#define BPF_COMPLEXITY_LIMIT_INSNS	131072
#define BPF_COMPLEXITY_LIMIT_STACK	1024
#define BPF_COMPLEXITY_LIMIT_STATES	64

#define BPF_MAP_PTR_UNPRIV	1UL
#define BPF_MAP_PTR_POISON	((void *)((0xeB9FUL << 1) +	\
@@ -3751,6 +3752,79 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *vstate,
	}
}

/* compute branch direction of the expression "if (reg opcode val) goto target;"
 * and return:
 *  1 - branch will be taken and "goto target" will be executed
 *  0 - branch will not be taken and fall-through to next insn
 * -1 - unknown. Example: "if (reg < 5)" is unknown when register value range [0,10]
 */
static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode)
{
	if (__is_pointer_value(false, reg))
		return -1;

	switch (opcode) {
	case BPF_JEQ:
		if (tnum_is_const(reg->var_off))
			return !!tnum_equals_const(reg->var_off, val);
		break;
	case BPF_JNE:
		if (tnum_is_const(reg->var_off))
			return !tnum_equals_const(reg->var_off, val);
		break;
	case BPF_JGT:
		if (reg->umin_value > val)
			return 1;
		else if (reg->umax_value <= val)
			return 0;
		break;
	case BPF_JSGT:
		if (reg->smin_value > (s64)val)
			return 1;
		else if (reg->smax_value < (s64)val)
			return 0;
		break;
	case BPF_JLT:
		if (reg->umax_value < val)
			return 1;
		else if (reg->umin_value >= val)
			return 0;
		break;
	case BPF_JSLT:
		if (reg->smax_value < (s64)val)
			return 1;
		else if (reg->smin_value >= (s64)val)
			return 0;
		break;
	case BPF_JGE:
		if (reg->umin_value >= val)
			return 1;
		else if (reg->umax_value < val)
			return 0;
		break;
	case BPF_JSGE:
		if (reg->smin_value >= (s64)val)
			return 1;
		else if (reg->smax_value < (s64)val)
			return 0;
		break;
	case BPF_JLE:
		if (reg->umax_value <= val)
			return 1;
		else if (reg->umin_value > val)
			return 0;
		break;
	case BPF_JSLE:
		if (reg->smax_value <= (s64)val)
			return 1;
		else if (reg->smin_value > (s64)val)
			return 0;
		break;
	}

	return -1;
}

/* Adjusts the register min/max values in the case that the dst_reg is the
 * variable register that we are working on, and src_reg is a constant or we're
 * simply doing a BPF_K check.
@@ -4152,21 +4226,15 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,

	dst_reg = &regs[insn->dst_reg];

	/* detect if R == 0 where R was initialized to zero earlier */
	if (BPF_SRC(insn->code) == BPF_K &&
	    (opcode == BPF_JEQ || opcode == BPF_JNE) &&
	    dst_reg->type == SCALAR_VALUE &&
	    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
			 */
	if (BPF_SRC(insn->code) == BPF_K) {
		int pred = is_branch_taken(dst_reg, insn->imm, opcode);

		if (pred == 1) {
			 /* only follow the goto, ignore fall-through */
			*insn_idx += insn->off;
			return 0;
		} else {
			/* if (imm != imm) goto pc+off;
			 * only follow fall-through branch, since
		} else if (pred == 0) {
			/* only follow fall-through branch, since
			 * that's where the program will go
			 */
			return 0;
@@ -4980,7 +5048,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
	struct bpf_verifier_state_list *new_sl;
	struct bpf_verifier_state_list *sl;
	struct bpf_verifier_state *cur = env->cur_state, *new;
	int i, j, err;
	int i, j, err, states_cnt = 0;

	sl = env->explored_states[insn_idx];
	if (!sl)
@@ -5007,8 +5075,12 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
			return 1;
		}
		sl = sl->next;
		states_cnt++;
	}

	if (!env->allow_ptr_leaks && states_cnt > BPF_COMPLEXITY_LIMIT_STATES)
		return 0;

	/* there were no equivalent states, remember current one.
	 * technically the current state is not proven to be safe yet,
	 * but it will either reach outer most bpf_exit (which means it's safe)
@@ -5148,6 +5220,9 @@ static int do_check(struct bpf_verifier_env *env)
			goto process_bpf_exit;
		}

		if (signal_pending(current))
			return -EAGAIN;

		if (need_resched())
			cond_resched();

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