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

Alexei Starovoitov says:

====================
pull-request: bpf-next 2019-05-31

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

Lots of exciting new features in the first PR of this developement cycle!
The main changes are:

1) misc verifier improvements, from Alexei.

2) bpftool can now convert btf to valid C, from Andrii.

3) verifier can insert explicit ZEXT insn when requested by 32-bit JITs.
   This feature greatly improves BPF speed on 32-bit architectures. From Jiong.

4) cgroups will now auto-detach bpf programs. This fixes issue of thousands
   bpf programs got stuck in dying cgroups. From Roman.

5) new bpf_send_signal() helper, from Yonghong.

6) cgroup inet skb programs can signal CN to the stack, from Lawrence.

7) miscellaneous cleanups, from many developers.
====================

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

6 files changed, 160 insertions, 18 deletions

diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index cb3c6b3b89c8..b631ee75762d 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -6,6 +6,7 @@
 #include <linux/errno.h>
 #include <linux/jump_label.h>
 #include <linux/percpu.h>
+#include <linux/percpu-refcount.h>
 #include <linux/rbtree.h>
 #include <uapi/linux/bpf.h>
 
@@ -71,11 +72,17 @@ struct cgroup_bpf {
 	u32 flags[MAX_BPF_ATTACH_TYPE];
 
 	/* temp storage for effective prog array used by prog_attach/detach */
-	struct bpf_prog_array __rcu *inactive;
+	struct bpf_prog_array *inactive;
+
+	/* reference counter used to detach bpf programs after cgroup removal */
+	struct percpu_ref refcnt;
+
+	/* cgroup_bpf is released using a work queue */
+	struct work_struct release_work;
 };
 
-void cgroup_bpf_put(struct cgroup *cgrp);
 int cgroup_bpf_inherit(struct cgroup *cgrp);
+void cgroup_bpf_offline(struct cgroup *cgrp);
 
 int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,
 			enum bpf_attach_type type, u32 flags);
@@ -283,8 +290,8 @@ int cgroup_bpf_prog_query(const union bpf_attr *attr,
 
 struct bpf_prog;
 struct cgroup_bpf {};
-static inline void cgroup_bpf_put(struct cgroup *cgrp) {}
 static inline int cgroup_bpf_inherit(struct cgroup *cgrp) { return 0; }
+static inline void cgroup_bpf_offline(struct cgroup *cgrp) {}
 
 static inline int cgroup_bpf_prog_attach(const union bpf_attr *attr,
 					 enum bpf_prog_type ptype,
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 4fb3aa2dc975..e5a309e6a400 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -66,6 +66,11 @@ struct bpf_map_ops {
 				     u64 imm, u32 *off);
 };
 
+struct bpf_map_memory {
+	u32 pages;
+	struct user_struct *user;
+};
+
 struct bpf_map {
 	/* The first two cachelines with read-mostly members of which some
 	 * are also accessed in fast-path (e.g. ops, max_entries).
@@ -86,7 +91,7 @@ struct bpf_map {
 	u32 btf_key_type_id;
 	u32 btf_value_type_id;
 	struct btf *btf;
-	u32 pages;
+	struct bpf_map_memory memory;
 	bool unpriv_array;
 	bool frozen; /* write-once */
 	/* 48 bytes hole */
@@ -94,8 +99,7 @@ struct bpf_map {
 	/* The 3rd and 4th cacheline with misc members to avoid false sharing
 	 * particularly with refcounting.
 	 */
-	struct user_struct *user ____cacheline_aligned;
-	atomic_t refcnt;
+	atomic_t refcnt ____cacheline_aligned;
 	atomic_t usercnt;
 	struct work_struct work;
 	char name[BPF_OBJ_NAME_LEN];
@@ -370,6 +374,7 @@ struct bpf_prog_aux {
 	u32 id;
 	u32 func_cnt; /* used by non-func prog as the number of func progs */
 	u32 func_idx; /* 0 for non-func prog, the index in func array for func prog */
+	bool verifier_zext; /* Zero extensions has been inserted by verifier. */
 	bool offload_requested;
 	struct bpf_prog **func;
 	void *jit_data; /* JIT specific data. arch dependent */
@@ -513,17 +518,17 @@ struct bpf_prog_array {
 };
 
 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags);
-void bpf_prog_array_free(struct bpf_prog_array __rcu *progs);
-int bpf_prog_array_length(struct bpf_prog_array __rcu *progs);
-int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs,
+void bpf_prog_array_free(struct bpf_prog_array *progs);
+int bpf_prog_array_length(struct bpf_prog_array *progs);
+int bpf_prog_array_copy_to_user(struct bpf_prog_array *progs,
 				__u32 __user *prog_ids, u32 cnt);
 
-void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *progs,
+void bpf_prog_array_delete_safe(struct bpf_prog_array *progs,
 				struct bpf_prog *old_prog);
-int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array,
+int bpf_prog_array_copy_info(struct bpf_prog_array *array,
 			     u32 *prog_ids, u32 request_cnt,
 			     u32 *prog_cnt);
-int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array,
+int bpf_prog_array_copy(struct bpf_prog_array *old_array,
 			struct bpf_prog *exclude_prog,
 			struct bpf_prog *include_prog,
 			struct bpf_prog_array **new_array);
@@ -551,6 +556,56 @@ _out:							\
 		_ret;					\
 	 })
 
+/* To be used by __cgroup_bpf_run_filter_skb for EGRESS BPF progs
+ * so BPF programs can request cwr for TCP packets.
+ *
+ * Current cgroup skb programs can only return 0 or 1 (0 to drop the
+ * packet. This macro changes the behavior so the low order bit
+ * indicates whether the packet should be dropped (0) or not (1)
+ * and the next bit is a congestion notification bit. This could be
+ * used by TCP to call tcp_enter_cwr()
+ *
+ * Hence, new allowed return values of CGROUP EGRESS BPF programs are:
+ *   0: drop packet
+ *   1: keep packet
+ *   2: drop packet and cn
+ *   3: keep packet and cn
+ *
+ * This macro then converts it to one of the NET_XMIT or an error
+ * code that is then interpreted as drop packet (and no cn):
+ *   0: NET_XMIT_SUCCESS  skb should be transmitted
+ *   1: NET_XMIT_DROP     skb should be dropped and cn
+ *   2: NET_XMIT_CN       skb should be transmitted and cn
+ *   3: -EPERM            skb should be dropped
+ */
+#define BPF_PROG_CGROUP_INET_EGRESS_RUN_ARRAY(array, ctx, func)		\
+	({						\
+		struct bpf_prog_array_item *_item;	\
+		struct bpf_prog *_prog;			\
+		struct bpf_prog_array *_array;		\
+		u32 ret;				\
+		u32 _ret = 1;				\
+		u32 _cn = 0;				\
+		preempt_disable();			\
+		rcu_read_lock();			\
+		_array = rcu_dereference(array);	\
+		_item = &_array->items[0];		\
+		while ((_prog = READ_ONCE(_item->prog))) {		\
+			bpf_cgroup_storage_set(_item->cgroup_storage);	\
+			ret = func(_prog, ctx);		\
+			_ret &= (ret & 1);		\
+			_cn |= (ret & 2);		\
+			_item++;			\
+		}					\
+		rcu_read_unlock();			\
+		preempt_enable();			\
+		if (_ret)				\
+			_ret = (_cn ? NET_XMIT_CN : NET_XMIT_SUCCESS);	\
+		else					\
+			_ret = (_cn ? NET_XMIT_DROP : -EPERM);		\
+		_ret;					\
+	})
+
 #define BPF_PROG_RUN_ARRAY(array, ctx, func)		\
 	__BPF_PROG_RUN_ARRAY(array, ctx, func, false)
 
@@ -595,9 +650,12 @@ struct bpf_map *__bpf_map_get(struct fd f);
 struct bpf_map * __must_check bpf_map_inc(struct bpf_map *map, bool uref);
 void bpf_map_put_with_uref(struct bpf_map *map);
 void bpf_map_put(struct bpf_map *map);
-int bpf_map_precharge_memlock(u32 pages);
 int bpf_map_charge_memlock(struct bpf_map *map, u32 pages);
 void bpf_map_uncharge_memlock(struct bpf_map *map, u32 pages);
+int bpf_map_charge_init(struct bpf_map_memory *mem, size_t size);
+void bpf_map_charge_finish(struct bpf_map_memory *mem);
+void bpf_map_charge_move(struct bpf_map_memory *dst,
+			 struct bpf_map_memory *src);
 void *bpf_map_area_alloc(size_t size, int numa_node);
 void bpf_map_area_free(void *base);
 void bpf_map_init_from_attr(struct bpf_map *map, union bpf_attr *attr);
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 1305ccbd8fe6..704ed7971472 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -36,9 +36,11 @@
  */
 enum bpf_reg_liveness {
 	REG_LIVE_NONE = 0, /* reg hasn't been read or written this branch */
-	REG_LIVE_READ, /* reg was read, so we're sensitive to initial value */
-	REG_LIVE_WRITTEN, /* reg was written first, screening off later reads */
-	REG_LIVE_DONE = 4, /* liveness won't be updating this register anymore */
+	REG_LIVE_READ32 = 0x1, /* reg was read, so we're sensitive to initial value */
+	REG_LIVE_READ64 = 0x2, /* likewise, but full 64-bit content matters */
+	REG_LIVE_READ = REG_LIVE_READ32 | REG_LIVE_READ64,
+	REG_LIVE_WRITTEN = 0x4, /* reg was written first, screening off later reads */
+	REG_LIVE_DONE = 0x8, /* liveness won't be updating this register anymore */
 };
 
 struct bpf_reg_state {
@@ -131,6 +133,11 @@ struct bpf_reg_state {
 	 * pointing to bpf_func_state.
 	 */
 	u32 frameno;
+	/* Tracks subreg definition. The stored value is the insn_idx of the
+	 * writing insn. This is safe because subreg_def is used before any insn
+	 * patching which only happens after main verification finished.
+	 */
+	s32 subreg_def;
 	enum bpf_reg_liveness live;
 };
 
@@ -187,6 +194,7 @@ struct bpf_func_state {
 struct bpf_verifier_state {
 	/* call stack tracking */
 	struct bpf_func_state *frame[MAX_CALL_FRAMES];
+	u32 insn_idx;
 	u32 curframe;
 	u32 active_spin_lock;
 	bool speculative;
@@ -232,7 +240,9 @@ struct bpf_insn_aux_data {
 	int ctx_field_size; /* the ctx field size for load insn, maybe 0 */
 	int sanitize_stack_off; /* stack slot to be cleared */
 	bool seen; /* this insn was processed by the verifier */
+	bool zext_dst; /* this insn zero extends dst reg */
 	u8 alu_state; /* used in combination with alu_limit */
+	bool prune_point;
 	unsigned int orig_idx; /* original instruction index */
 };
 
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index c0077adeea83..49e8facf7c4a 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -924,4 +924,22 @@ static inline bool cgroup_task_frozen(struct task_struct *task)
 
 #endif /* !CONFIG_CGROUPS */
 
+#ifdef CONFIG_CGROUP_BPF
+static inline void cgroup_bpf_get(struct cgroup *cgrp)
+{
+	percpu_ref_get(&cgrp->bpf.refcnt);
+}
+
+static inline void cgroup_bpf_put(struct cgroup *cgrp)
+{
+	percpu_ref_put(&cgrp->bpf.refcnt);
+}
+
+#else /* CONFIG_CGROUP_BPF */
+
+static inline void cgroup_bpf_get(struct cgroup *cgrp) {}
+static inline void cgroup_bpf_put(struct cgroup *cgrp) {}
+
+#endif /* CONFIG_CGROUP_BPF */
+
 #endif /* _LINUX_CGROUP_H */
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 7148bab96943..43b45d6db36d 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -160,6 +160,20 @@ struct ctl_table_header;
 		.off   = 0,					\
 		.imm   = IMM })
 
+/* Special form of mov32, used for doing explicit zero extension on dst. */
+#define BPF_ZEXT_REG(DST)					\
+	((struct bpf_insn) {					\
+		.code  = BPF_ALU | BPF_MOV | BPF_X,		\
+		.dst_reg = DST,					\
+		.src_reg = DST,					\
+		.off   = 0,					\
+		.imm   = 1 })
+
+static inline bool insn_is_zext(const struct bpf_insn *insn)
+{
+	return insn->code == (BPF_ALU | BPF_MOV | BPF_X) && insn->imm == 1;
+}
+
 /* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
 #define BPF_LD_IMM64(DST, IMM)					\
 	BPF_LD_IMM64_RAW(DST, 0, IMM)
@@ -512,7 +526,8 @@ struct bpf_prog {
 				blinded:1,	/* Was blinded */
 				is_func:1,	/* program is a bpf function */
 				kprobe_override:1, /* Do we override a kprobe? */
-				has_callchain_buf:1; /* callchain buffer allocated? */
+				has_callchain_buf:1, /* callchain buffer allocated? */
+				enforce_expected_attach_type:1; /* Enforce expected_attach_type checking at attach time */
 	enum bpf_prog_type	type;		/* Type of BPF program */
 	enum bpf_attach_type	expected_attach_type; /* For some prog types */
 	u32			len;		/* Number of filter blocks */
@@ -811,6 +826,7 @@ u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 
 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog);
 void bpf_jit_compile(struct bpf_prog *prog);
+bool bpf_jit_needs_zext(void);
 bool bpf_helper_changes_pkt_data(void *func);
 
 static inline bool bpf_dump_raw_ok(void)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 63e0cf66f01a..7c6aef253173 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -260,6 +260,24 @@ enum bpf_attach_type {
  */
 #define BPF_F_ANY_ALIGNMENT	(1U << 1)
 
+/* BPF_F_TEST_RND_HI32 is used in BPF_PROG_LOAD command for testing purpose.
+ * Verifier does sub-register def/use analysis and identifies instructions whose
+ * def only matters for low 32-bit, high 32-bit is never referenced later
+ * through implicit zero extension. Therefore verifier notifies JIT back-ends
+ * that it is safe to ignore clearing high 32-bit for these instructions. This
+ * saves some back-ends a lot of code-gen. However such optimization is not
+ * necessary on some arches, for example x86_64, arm64 etc, whose JIT back-ends
+ * hence hasn't used verifier's analysis result. But, we really want to have a
+ * way to be able to verify the correctness of the described optimization on
+ * x86_64 on which testsuites are frequently exercised.
+ *
+ * So, this flag is introduced. Once it is set, verifier will randomize high
+ * 32-bit for those instructions who has been identified as safe to ignore them.
+ * Then, if verifier is not doing correct analysis, such randomization will
+ * regress tests to expose bugs.
+ */
+#define BPF_F_TEST_RND_HI32	(1U << 2)
+
 /* When BPF ldimm64's insn[0].src_reg != 0 then this can have
  * two extensions:
  *
@@ -2672,6 +2690,20 @@ union bpf_attr {
  *		0 on success.
  *
  *		**-ENOENT** if the bpf-local-storage cannot be found.
+ *
+ * int bpf_send_signal(u32 sig)
+ *	Description
+ *		Send signal *sig* to the current task.
+ *	Return
+ *		0 on success or successfully queued.
+ *
+ *		**-EBUSY** if work queue under nmi is full.
+ *
+ *		**-EINVAL** if *sig* is invalid.
+ *
+ *		**-EPERM** if no permission to send the *sig*.
+ *
+ *		**-EAGAIN** if bpf program can try again.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -2782,7 +2814,8 @@ union bpf_attr {
 	FN(strtol),			\
 	FN(strtoul),			\
 	FN(sk_storage_get),		\
-	FN(sk_storage_delete),
+	FN(sk_storage_delete),		\
+	FN(send_signal),
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
  * function eBPF program intends to call