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

Daniel Borkmann says:

====================
pull-request: bpf 2021-05-26

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

We've added 14 non-merge commits during the last 14 day(s) which contain
a total of 17 files changed, 513 insertions(+), 231 deletions(-).

The main changes are:

1) Fix bpf_skb_change_head() helper to reset mac_len, from Jussi Maki.

2) Fix masking direction swap upon off-reg sign change, from Daniel Borkmann.

3) Fix BPF offloads in verifier by reordering driver callback, from Yinjun Zhang.

4) BPF selftest for ringbuf mmap ro/rw restrictions, from Andrii Nakryiko.

5) Follow-up fixes to nested bprintf per-cpu buffers, from Florent Revest.

6) Fix bpftool sock_release attach point help info, from Liu Jian.
====================

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

arch/arm64/Kbuild

@@ -1,6 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
-obj-y			+= kernel/ mm/
-obj-$(CONFIG_NET)	+= net/
+obj-y			+= kernel/ mm/ net/
 obj-$(CONFIG_KVM)	+= kvm/
 obj-$(CONFIG_XEN)	+= xen/
 obj-$(CONFIG_CRYPTO)	+= crypto/

kernel/bpf/Kconfig

@@ -37,6 +37,7 @@ config BPF_SYSCALL
 
 config BPF_JIT
 	bool "Enable BPF Just In Time compiler"
+	depends on BPF
 	depends on HAVE_CBPF_JIT || HAVE_EBPF_JIT
 	depends on MODULES
 	help

kernel/bpf/bpf_lsm.c

@@ -107,10 +107,12 @@ bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_inode_storage_get_proto;
 	case BPF_FUNC_inode_storage_delete:
 		return &bpf_inode_storage_delete_proto;
+#ifdef CONFIG_NET
 	case BPF_FUNC_sk_storage_get:
 		return &bpf_sk_storage_get_proto;
 	case BPF_FUNC_sk_storage_delete:
 		return &bpf_sk_storage_delete_proto;
+#endif /* CONFIG_NET */
 	case BPF_FUNC_spin_lock:
 		return &bpf_spin_lock_proto;
 	case BPF_FUNC_spin_unlock:

kernel/bpf/helpers.c

@@ -692,13 +692,15 @@ static int bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
 	return -EINVAL;
 }
 
-/* Per-cpu temp buffers which can be used by printf-like helpers for %s or %p
+/* Per-cpu temp buffers used by printf-like helpers to store the bprintf binary
+ * arguments representation.
  */
-#define MAX_PRINTF_BUF_LEN	512
+#define MAX_BPRINTF_BUF_LEN	512
 
 /* Support executing three nested bprintf helper calls on a given CPU */
+#define MAX_BPRINTF_NEST_LEVEL	3
 struct bpf_bprintf_buffers {
-	char tmp_bufs[3][MAX_PRINTF_BUF_LEN];
+	char tmp_bufs[MAX_BPRINTF_NEST_LEVEL][MAX_BPRINTF_BUF_LEN];
 };
 static DEFINE_PER_CPU(struct bpf_bprintf_buffers, bpf_bprintf_bufs);
 static DEFINE_PER_CPU(int, bpf_bprintf_nest_level);
@@ -710,7 +712,7 @@ static int try_get_fmt_tmp_buf(char **tmp_buf)
 
 	preempt_disable();
 	nest_level = this_cpu_inc_return(bpf_bprintf_nest_level);
-	if (WARN_ON_ONCE(nest_level > ARRAY_SIZE(bufs->tmp_bufs))) {
+	if (WARN_ON_ONCE(nest_level > MAX_BPRINTF_NEST_LEVEL)) {
 		this_cpu_dec(bpf_bprintf_nest_level);
 		preempt_enable();
 		return -EBUSY;
@@ -761,7 +763,7 @@ int bpf_bprintf_prepare(char *fmt, u32 fmt_size, const u64 *raw_args,
 		if (num_args && try_get_fmt_tmp_buf(&tmp_buf))
 			return -EBUSY;
 
-		tmp_buf_end = tmp_buf + MAX_PRINTF_BUF_LEN;
+		tmp_buf_end = tmp_buf + MAX_BPRINTF_BUF_LEN;
 		*bin_args = (u32 *)tmp_buf;
 	}
 

kernel/bpf/verifier.c

@@ -6409,18 +6409,10 @@ enum {
 };
 
 static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg,
-			      const struct bpf_reg_state *off_reg,
-			      u32 *alu_limit, u8 opcode)
+			      u32 *alu_limit, bool mask_to_left)
 {
-	bool off_is_neg = off_reg->smin_value < 0;
-	bool mask_to_left = (opcode == BPF_ADD &&  off_is_neg) ||
-			    (opcode == BPF_SUB && !off_is_neg);
 	u32 max = 0, ptr_limit = 0;
 
-	if (!tnum_is_const(off_reg->var_off) &&
-	    (off_reg->smin_value < 0) != (off_reg->smax_value < 0))
-		return REASON_BOUNDS;
-
 	switch (ptr_reg->type) {
 	case PTR_TO_STACK:
 		/* Offset 0 is out-of-bounds, but acceptable start for the
@@ -6486,15 +6478,20 @@ static bool sanitize_needed(u8 opcode)
 	return opcode == BPF_ADD || opcode == BPF_SUB;
 }
 
+struct bpf_sanitize_info {
+	struct bpf_insn_aux_data aux;
+	bool mask_to_left;
+};
+
 static int sanitize_ptr_alu(struct bpf_verifier_env *env,
 			    struct bpf_insn *insn,
 			    const struct bpf_reg_state *ptr_reg,
 			    const struct bpf_reg_state *off_reg,
 			    struct bpf_reg_state *dst_reg,
-			    struct bpf_insn_aux_data *tmp_aux,
+			    struct bpf_sanitize_info *info,
 			    const bool commit_window)
 {
-	struct bpf_insn_aux_data *aux = commit_window ? cur_aux(env) : tmp_aux;
+	struct bpf_insn_aux_data *aux = commit_window ? cur_aux(env) : &info->aux;
 	struct bpf_verifier_state *vstate = env->cur_state;
 	bool off_is_imm = tnum_is_const(off_reg->var_off);
 	bool off_is_neg = off_reg->smin_value < 0;
@@ -6515,16 +6512,25 @@ static int sanitize_ptr_alu(struct bpf_verifier_env *env,
 	if (vstate->speculative)
 		goto do_sim;
 
-	err = retrieve_ptr_limit(ptr_reg, off_reg, &alu_limit, opcode);
+	if (!commit_window) {
+		if (!tnum_is_const(off_reg->var_off) &&
+		    (off_reg->smin_value < 0) != (off_reg->smax_value < 0))
+			return REASON_BOUNDS;
+
+		info->mask_to_left = (opcode == BPF_ADD &&  off_is_neg) ||
+				     (opcode == BPF_SUB && !off_is_neg);
+	}
+
+	err = retrieve_ptr_limit(ptr_reg, &alu_limit, info->mask_to_left);
 	if (err < 0)
 		return err;
 
 	if (commit_window) {
 		/* In commit phase we narrow the masking window based on
 		 * the observed pointer move after the simulated operation.
 		 */
-		alu_state = tmp_aux->alu_state;
-		alu_limit = abs(tmp_aux->alu_limit - alu_limit);
+		alu_state = info->aux.alu_state;
+		alu_limit = abs(info->aux.alu_limit - alu_limit);
 	} else {
 		alu_state  = off_is_neg ? BPF_ALU_NEG_VALUE : 0;
 		alu_state |= off_is_imm ? BPF_ALU_IMMEDIATE : 0;
@@ -6539,8 +6545,12 @@ static int sanitize_ptr_alu(struct bpf_verifier_env *env,
 	/* If we're in commit phase, we're done here given we already
 	 * pushed the truncated dst_reg into the speculative verification
 	 * stack.
+	 *
+	 * Also, when register is a known constant, we rewrite register-based
+	 * operation to immediate-based, and thus do not need masking (and as
+	 * a consequence, do not need to simulate the zero-truncation either).
 	 */
-	if (commit_window)
+	if (commit_window || off_is_imm)
 		return 0;
 
 	/* Simulate and find potential out-of-bounds access under
@@ -6685,7 +6695,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
 	    smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value;
 	u64 umin_val = off_reg->umin_value, umax_val = off_reg->umax_value,
 	    umin_ptr = ptr_reg->umin_value, umax_ptr = ptr_reg->umax_value;
-	struct bpf_insn_aux_data tmp_aux = {};
+	struct bpf_sanitize_info info = {};
 	u8 opcode = BPF_OP(insn->code);
 	u32 dst = insn->dst_reg;
 	int ret;
@@ -6754,7 +6764,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
 
 	if (sanitize_needed(opcode)) {
 		ret = sanitize_ptr_alu(env, insn, ptr_reg, off_reg, dst_reg,
-				       &tmp_aux, false);
+				       &info, false);
 		if (ret < 0)
 			return sanitize_err(env, insn, ret, off_reg, dst_reg);
 	}
@@ -6895,7 +6905,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
 		return -EACCES;
 	if (sanitize_needed(opcode)) {
 		ret = sanitize_ptr_alu(env, insn, dst_reg, off_reg, dst_reg,
-				       &tmp_aux, true);
+				       &info, true);
 		if (ret < 0)
 			return sanitize_err(env, insn, ret, off_reg, dst_reg);
 	}
@@ -13368,12 +13378,6 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
 	if (is_priv)
 		env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;
 
-	if (bpf_prog_is_dev_bound(env->prog->aux)) {
-		ret = bpf_prog_offload_verifier_prep(env->prog);
-		if (ret)
-			goto skip_full_check;
-	}
-
 	env->explored_states = kvcalloc(state_htab_size(env),
 				       sizeof(struct bpf_verifier_state_list *),
 				       GFP_USER);
@@ -13401,6 +13405,12 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
 	if (ret < 0)
 		goto skip_full_check;
 
+	if (bpf_prog_is_dev_bound(env->prog->aux)) {
+		ret = bpf_prog_offload_verifier_prep(env->prog);
+		if (ret)
+			goto skip_full_check;
+	}
+
 	ret = check_cfg(env);
 	if (ret < 0)
 		goto skip_full_check;

net/core/filter.c

@@ -3784,6 +3784,7 @@ static inline int __bpf_skb_change_head(struct sk_buff *skb, u32 head_room,
 		__skb_push(skb, head_room);
 		memset(skb->data, 0, head_room);
 		skb_reset_mac_header(skb);
+		skb_reset_mac_len(skb);
 	}
 
 	return ret;

tools/bpf/bpftool/Documentation/bpftool-cgroup.rst

@@ -30,7 +30,8 @@ CGROUP COMMANDS
 |	*ATTACH_TYPE* := { **ingress** | **egress** | **sock_create** | **sock_ops** | **device** |
 |		**bind4** | **bind6** | **post_bind4** | **post_bind6** | **connect4** | **connect6** |
 |               **getpeername4** | **getpeername6** | **getsockname4** | **getsockname6** | **sendmsg4** |
-|               **sendmsg6** | **recvmsg4** | **recvmsg6** | **sysctl** | **getsockopt** | **setsockopt** }
+|               **sendmsg6** | **recvmsg4** | **recvmsg6** | **sysctl** | **getsockopt** | **setsockopt** |
+|               **sock_release** }
 |	*ATTACH_FLAGS* := { **multi** | **override** }
 
 DESCRIPTION
@@ -106,6 +107,7 @@ DESCRIPTION
 		  **getpeername6** call to getpeername(2) for an inet6 socket (since 5.8);
 		  **getsockname4** call to getsockname(2) for an inet4 socket (since 5.8);
 		  **getsockname6** call to getsockname(2) for an inet6 socket (since 5.8).
+		  **sock_release** closing an userspace inet socket (since 5.9).
 
 	**bpftool cgroup detach** *CGROUP* *ATTACH_TYPE* *PROG*
 		  Detach *PROG* from the cgroup *CGROUP* and attach type

tools/bpf/bpftool/Documentation/bpftool-prog.rst

@@ -44,7 +44,7 @@ PROG COMMANDS
 |		**cgroup/connect4** | **cgroup/connect6** | **cgroup/getpeername4** | **cgroup/getpeername6** |
 |               **cgroup/getsockname4** | **cgroup/getsockname6** | **cgroup/sendmsg4** | **cgroup/sendmsg6** |
 |		**cgroup/recvmsg4** | **cgroup/recvmsg6** | **cgroup/sysctl** |
-|		**cgroup/getsockopt** | **cgroup/setsockopt** |
+|		**cgroup/getsockopt** | **cgroup/setsockopt** | **cgroup/sock_release** |
 |		**struct_ops** | **fentry** | **fexit** | **freplace** | **sk_lookup**
 |	}
 |       *ATTACH_TYPE* := {

tools/bpf/bpftool/bash-completion/bpftool

@@ -478,7 +478,7 @@ _bpftool()
                                 cgroup/recvmsg4 cgroup/recvmsg6 \
                                 cgroup/post_bind4 cgroup/post_bind6 \
                                 cgroup/sysctl cgroup/getsockopt \
-                                cgroup/setsockopt struct_ops \
+                                cgroup/setsockopt cgroup/sock_release struct_ops \
                                 fentry fexit freplace sk_lookup" -- \
                                                    "$cur" ) )
                             return 0
@@ -1021,7 +1021,7 @@ _bpftool()
                         device bind4 bind6 post_bind4 post_bind6 connect4 connect6 \
                         getpeername4 getpeername6 getsockname4 getsockname6 \
                         sendmsg4 sendmsg6 recvmsg4 recvmsg6 sysctl getsockopt \
-                        setsockopt'
+                        setsockopt sock_release'
                     local ATTACH_FLAGS='multi override'
                     local PROG_TYPE='id pinned tag name'
                     case $prev in
@@ -1032,7 +1032,7 @@ _bpftool()
                         ingress|egress|sock_create|sock_ops|device|bind4|bind6|\
                         post_bind4|post_bind6|connect4|connect6|getpeername4|\
                         getpeername6|getsockname4|getsockname6|sendmsg4|sendmsg6|\
-                        recvmsg4|recvmsg6|sysctl|getsockopt|setsockopt)
+                        recvmsg4|recvmsg6|sysctl|getsockopt|setsockopt|sock_release)
                             COMPREPLY=( $( compgen -W "$PROG_TYPE" -- \
                                 "$cur" ) )
                             return 0

tools/bpf/bpftool/cgroup.c

@@ -28,7 +28,8 @@
 	"                        connect6 | getpeername4 | getpeername6 |\n"   \
 	"                        getsockname4 | getsockname6 | sendmsg4 |\n"   \
 	"                        sendmsg6 | recvmsg4 | recvmsg6 |\n"           \
-	"                        sysctl | getsockopt | setsockopt }"
+	"                        sysctl | getsockopt | setsockopt |\n"	       \
+	"                        sock_release }"
 
 static unsigned int query_flags;
 

tools/bpf/bpftool/prog.c

@@ -2138,7 +2138,7 @@ static int do_help(int argc, char **argv)
 		"                 cgroup/getpeername4 | cgroup/getpeername6 |\n"
 		"                 cgroup/getsockname4 | cgroup/getsockname6 | cgroup/sendmsg4 |\n"
 		"                 cgroup/sendmsg6 | cgroup/recvmsg4 | cgroup/recvmsg6 |\n"
-		"                 cgroup/getsockopt | cgroup/setsockopt |\n"
+		"                 cgroup/getsockopt | cgroup/setsockopt | cgroup/sock_release |\n"
 		"                 struct_ops | fentry | fexit | freplace | sk_lookup }\n"
 		"       ATTACH_TYPE := { msg_verdict | stream_verdict | stream_parser |\n"
 		"                        flow_dissector }\n"

tools/testing/selftests/bpf/prog_tests/ringbuf.c

@@ -86,8 +86,9 @@ void test_ringbuf(void)
 	const size_t rec_sz = BPF_RINGBUF_HDR_SZ + sizeof(struct sample);
 	pthread_t thread;
 	long bg_ret = -1;
-	int err, cnt;
+	int err, cnt, rb_fd;
 	int page_size = getpagesize();
+	void *mmap_ptr, *tmp_ptr;
 
 	skel = test_ringbuf__open();
 	if (CHECK(!skel, "skel_open", "skeleton open failed\n"))
@@ -101,6 +102,52 @@ void test_ringbuf(void)
 	if (CHECK(err != 0, "skel_load", "skeleton load failed\n"))
 		goto cleanup;
 
+	rb_fd = bpf_map__fd(skel->maps.ringbuf);
+	/* good read/write cons_pos */
+	mmap_ptr = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, rb_fd, 0);
+	ASSERT_OK_PTR(mmap_ptr, "rw_cons_pos");
+	tmp_ptr = mremap(mmap_ptr, page_size, 2 * page_size, MREMAP_MAYMOVE);
+	if (!ASSERT_ERR_PTR(tmp_ptr, "rw_extend"))
+		goto cleanup;
+	ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_EXEC), "exec_cons_pos_protect");
+	ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_rw");
+
+	/* bad writeable prod_pos */
+	mmap_ptr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, rb_fd, page_size);
+	err = -errno;
+	ASSERT_ERR_PTR(mmap_ptr, "wr_prod_pos");
+	ASSERT_EQ(err, -EPERM, "wr_prod_pos_err");
+
+	/* bad writeable data pages */
+	mmap_ptr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, rb_fd, 2 * page_size);
+	err = -errno;
+	ASSERT_ERR_PTR(mmap_ptr, "wr_data_page_one");
+	ASSERT_EQ(err, -EPERM, "wr_data_page_one_err");
+	mmap_ptr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, rb_fd, 3 * page_size);
+	ASSERT_ERR_PTR(mmap_ptr, "wr_data_page_two");
+	mmap_ptr = mmap(NULL, 2 * page_size, PROT_WRITE, MAP_SHARED, rb_fd, 2 * page_size);
+	ASSERT_ERR_PTR(mmap_ptr, "wr_data_page_all");
+
+	/* good read-only pages */
+	mmap_ptr = mmap(NULL, 4 * page_size, PROT_READ, MAP_SHARED, rb_fd, 0);
+	if (!ASSERT_OK_PTR(mmap_ptr, "ro_prod_pos"))
+		goto cleanup;
+
+	ASSERT_ERR(mprotect(mmap_ptr, 4 * page_size, PROT_WRITE), "write_protect");
+	ASSERT_ERR(mprotect(mmap_ptr, 4 * page_size, PROT_EXEC), "exec_protect");
+	ASSERT_ERR_PTR(mremap(mmap_ptr, 0, 4 * page_size, MREMAP_MAYMOVE), "ro_remap");
+	ASSERT_OK(munmap(mmap_ptr, 4 * page_size), "unmap_ro");
+
+	/* good read-only pages with initial offset */
+	mmap_ptr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, rb_fd, page_size);
+	if (!ASSERT_OK_PTR(mmap_ptr, "ro_prod_pos"))
+		goto cleanup;
+
+	ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_WRITE), "write_protect");
+	ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_EXEC), "exec_protect");
+	ASSERT_ERR_PTR(mremap(mmap_ptr, 0, 3 * page_size, MREMAP_MAYMOVE), "ro_remap");
+	ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_ro");
+
 	/* only trigger BPF program for current process */
 	skel->bss->pid = getpid();