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

Alexei Starovoitov says:

====================
pull-request: bpf 2021-04-01

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

We've added 11 non-merge commits during the last 8 day(s) which contain
a total of 10 files changed, 151 insertions(+), 26 deletions(-).

The main changes are:

1) xsk creation fixes, from Ciara.

2) bpf_get_task_stack fix, from Dave.

3) trampoline in modules fix, from Jiri.

4) bpf_obj_get fix for links and progs, from Lorenz.

5) struct_ops progs must be gpl compatible fix, from Toke.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/bpf.h

@@ -40,6 +40,7 @@ struct bpf_local_storage;
 struct bpf_local_storage_map;
 struct kobject;
 struct mem_cgroup;
+struct module;
 
 extern struct idr btf_idr;
 extern spinlock_t btf_idr_lock;
@@ -623,6 +624,7 @@ struct bpf_trampoline {
 	/* Executable image of trampoline */
 	struct bpf_tramp_image *cur_image;
 	u64 selector;
+	struct module *mod;
 };
 
 struct bpf_attach_target_info {

kernel/bpf/disasm.c

@@ -84,7 +84,7 @@ static const char *const bpf_atomic_alu_string[16] = {
 	[BPF_ADD >> 4]  = "add",
 	[BPF_AND >> 4]  = "and",
 	[BPF_OR >> 4]  = "or",
-	[BPF_XOR >> 4]  = "or",
+	[BPF_XOR >> 4]  = "xor",
 };
 
 static const char *const bpf_ldst_string[] = {

kernel/bpf/inode.c

@@ -543,11 +543,11 @@ int bpf_obj_get_user(const char __user *pathname, int flags)
 		return PTR_ERR(raw);
 
 	if (type == BPF_TYPE_PROG)
-		ret = bpf_prog_new_fd(raw);
+		ret = (f_flags != O_RDWR) ? -EINVAL : bpf_prog_new_fd(raw);
 	else if (type == BPF_TYPE_MAP)
 		ret = bpf_map_new_fd(raw, f_flags);
 	else if (type == BPF_TYPE_LINK)
-		ret = bpf_link_new_fd(raw);
+		ret = (f_flags != O_RDWR) ? -EINVAL : bpf_link_new_fd(raw);
 	else
 		return -ENOENT;
 

kernel/bpf/stackmap.c

@@ -517,9 +517,17 @@ const struct bpf_func_proto bpf_get_stack_proto = {
 BPF_CALL_4(bpf_get_task_stack, struct task_struct *, task, void *, buf,
 	   u32, size, u64, flags)
 {
-	struct pt_regs *regs = task_pt_regs(task);
+	struct pt_regs *regs;
+	long res;
 
-	return __bpf_get_stack(regs, task, NULL, buf, size, flags);
+	if (!try_get_task_stack(task))
+		return -EFAULT;
+
+	regs = task_pt_regs(task);
+	res = __bpf_get_stack(regs, task, NULL, buf, size, flags);
+	put_task_stack(task);
+
+	return res;
 }
 
 BTF_ID_LIST_SINGLE(bpf_get_task_stack_btf_ids, struct, task_struct)

kernel/bpf/trampoline.c

@@ -9,6 +9,7 @@
 #include <linux/btf.h>
 #include <linux/rcupdate_trace.h>
 #include <linux/rcupdate_wait.h>
+#include <linux/module.h>
 
 /* dummy _ops. The verifier will operate on target program's ops. */
 const struct bpf_verifier_ops bpf_extension_verifier_ops = {
@@ -87,6 +88,26 @@ static struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
 	return tr;
 }
 
+static int bpf_trampoline_module_get(struct bpf_trampoline *tr)
+{
+	struct module *mod;
+	int err = 0;
+
+	preempt_disable();
+	mod = __module_text_address((unsigned long) tr->func.addr);
+	if (mod && !try_module_get(mod))
+		err = -ENOENT;
+	preempt_enable();
+	tr->mod = mod;
+	return err;
+}
+
+static void bpf_trampoline_module_put(struct bpf_trampoline *tr)
+{
+	module_put(tr->mod);
+	tr->mod = NULL;
+}
+
 static int is_ftrace_location(void *ip)
 {
 	long addr;
@@ -108,6 +129,9 @@ static int unregister_fentry(struct bpf_trampoline *tr, void *old_addr)
 		ret = unregister_ftrace_direct((long)ip, (long)old_addr);
 	else
 		ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, old_addr, NULL);
+
+	if (!ret)
+		bpf_trampoline_module_put(tr);
 	return ret;
 }
 
@@ -134,10 +158,16 @@ static int register_fentry(struct bpf_trampoline *tr, void *new_addr)
 		return ret;
 	tr->func.ftrace_managed = ret;
 
+	if (bpf_trampoline_module_get(tr))
+		return -ENOENT;
+
 	if (tr->func.ftrace_managed)
 		ret = register_ftrace_direct((long)ip, (long)new_addr);
 	else
 		ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, NULL, new_addr);
+
+	if (ret)
+		bpf_trampoline_module_put(tr);
 	return ret;
 }
 

kernel/bpf/verifier.c

@@ -12158,6 +12158,11 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env)
 	u32 btf_id, member_idx;
 	const char *mname;
 
+	if (!prog->gpl_compatible) {
+		verbose(env, "struct ops programs must have a GPL compatible license\n");
+		return -EINVAL;
+	}
+
 	btf_id = prog->aux->attach_btf_id;
 	st_ops = bpf_struct_ops_find(btf_id);
 	if (!st_ops) {

tools/lib/bpf/ringbuf.c

@@ -227,7 +227,7 @@ static int ringbuf_process_ring(struct ring* r)
 			if ((len & BPF_RINGBUF_DISCARD_BIT) == 0) {
 				sample = (void *)len_ptr + BPF_RINGBUF_HDR_SZ;
 				err = r->sample_cb(r->ctx, sample, len);
-				if (err) {
+				if (err < 0) {
 					/* update consumer pos and bail out */
 					smp_store_release(r->consumer_pos,
 							  cons_pos);

tools/lib/bpf/xsk.c

@@ -59,6 +59,8 @@ struct xsk_umem {
 	int fd;
 	int refcount;
 	struct list_head ctx_list;
+	bool rx_ring_setup_done;
+	bool tx_ring_setup_done;
 };
 
 struct xsk_ctx {
@@ -743,26 +745,30 @@ static struct xsk_ctx *xsk_get_ctx(struct xsk_umem *umem, int ifindex,
 	return NULL;
 }
 
-static void xsk_put_ctx(struct xsk_ctx *ctx)
+static void xsk_put_ctx(struct xsk_ctx *ctx, bool unmap)
 {
 	struct xsk_umem *umem = ctx->umem;
 	struct xdp_mmap_offsets off;
 	int err;
 
-	if (--ctx->refcount == 0) {
+	if (--ctx->refcount)
+		return;
+
+	if (!unmap)
+		goto out_free;
+
 	err = xsk_get_mmap_offsets(umem->fd, &off);
-		if (!err) {
-			munmap(ctx->fill->ring - off.fr.desc,
-			       off.fr.desc + umem->config.fill_size *
+	if (err)
+		goto out_free;
+
+	munmap(ctx->fill->ring - off.fr.desc, off.fr.desc + umem->config.fill_size *
 	       sizeof(__u64));
-			munmap(ctx->comp->ring - off.cr.desc,
-			       off.cr.desc + umem->config.comp_size *
+	munmap(ctx->comp->ring - off.cr.desc, off.cr.desc + umem->config.comp_size *
 	       sizeof(__u64));
-		}
 
+out_free:
 	list_del(&ctx->list);
 	free(ctx);
-	}
 }
 
 static struct xsk_ctx *xsk_create_ctx(struct xsk_socket *xsk,
@@ -797,8 +803,6 @@ static struct xsk_ctx *xsk_create_ctx(struct xsk_socket *xsk,
 	memcpy(ctx->ifname, ifname, IFNAMSIZ - 1);
 	ctx->ifname[IFNAMSIZ - 1] = '\0';
 
-	umem->fill_save = NULL;
-	umem->comp_save = NULL;
 	ctx->fill = fill;
 	ctx->comp = comp;
 	list_add(&ctx->list, &umem->ctx_list);
@@ -854,6 +858,8 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr,
 	struct xsk_socket *xsk;
 	struct xsk_ctx *ctx;
 	int err, ifindex;
+	bool unmap = umem->fill_save != fill;
+	bool rx_setup_done = false, tx_setup_done = false;
 
 	if (!umem || !xsk_ptr || !(rx || tx))
 		return -EFAULT;
@@ -881,6 +887,8 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr,
 		}
 	} else {
 		xsk->fd = umem->fd;
+		rx_setup_done = umem->rx_ring_setup_done;
+		tx_setup_done = umem->tx_ring_setup_done;
 	}
 
 	ctx = xsk_get_ctx(umem, ifindex, queue_id);
@@ -899,7 +907,7 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr,
 	}
 	xsk->ctx = ctx;
 
-	if (rx) {
+	if (rx && !rx_setup_done) {
 		err = setsockopt(xsk->fd, SOL_XDP, XDP_RX_RING,
 				 &xsk->config.rx_size,
 				 sizeof(xsk->config.rx_size));
@@ -907,8 +915,10 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr,
 			err = -errno;
 			goto out_put_ctx;
 		}
+		if (xsk->fd == umem->fd)
+			umem->rx_ring_setup_done = true;
 	}
-	if (tx) {
+	if (tx && !tx_setup_done) {
 		err = setsockopt(xsk->fd, SOL_XDP, XDP_TX_RING,
 				 &xsk->config.tx_size,
 				 sizeof(xsk->config.tx_size));
@@ -916,6 +926,8 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr,
 			err = -errno;
 			goto out_put_ctx;
 		}
+		if (xsk->fd == umem->fd)
+			umem->rx_ring_setup_done = true;
 	}
 
 	err = xsk_get_mmap_offsets(xsk->fd, &off);
@@ -994,6 +1006,8 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr,
 	}
 
 	*xsk_ptr = xsk;
+	umem->fill_save = NULL;
+	umem->comp_save = NULL;
 	return 0;
 
 out_mmap_tx:
@@ -1005,7 +1019,7 @@ int xsk_socket__create_shared(struct xsk_socket **xsk_ptr,
 		munmap(rx_map, off.rx.desc +
 		       xsk->config.rx_size * sizeof(struct xdp_desc));
 out_put_ctx:
-	xsk_put_ctx(ctx);
+	xsk_put_ctx(ctx, unmap);
 out_socket:
 	if (--umem->refcount)
 		close(xsk->fd);
@@ -1019,6 +1033,9 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname,
 		       struct xsk_ring_cons *rx, struct xsk_ring_prod *tx,
 		       const struct xsk_socket_config *usr_config)
 {
+	if (!umem)
+		return -EFAULT;
+
 	return xsk_socket__create_shared(xsk_ptr, ifname, queue_id, umem,
 					 rx, tx, umem->fill_save,
 					 umem->comp_save, usr_config);
@@ -1068,7 +1085,7 @@ void xsk_socket__delete(struct xsk_socket *xsk)
 		}
 	}
 
-	xsk_put_ctx(ctx);
+	xsk_put_ctx(ctx, true);
 
 	umem->refcount--;
 	/* Do not close an fd that also has an associated umem connected

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

@@ -6,6 +6,7 @@
 #include <test_progs.h>
 #include "bpf_dctcp.skel.h"
 #include "bpf_cubic.skel.h"
+#include "bpf_tcp_nogpl.skel.h"
 
 #define min(a, b) ((a) < (b) ? (a) : (b))
 
@@ -227,10 +228,53 @@ static void test_dctcp(void)
 	bpf_dctcp__destroy(dctcp_skel);
 }
 
+static char *err_str;
+static bool found;
+
+static int libbpf_debug_print(enum libbpf_print_level level,
+			      const char *format, va_list args)
+{
+	char *log_buf;
+
+	if (level != LIBBPF_WARN ||
+	    strcmp(format, "libbpf: \n%s\n")) {
+		vprintf(format, args);
+		return 0;
+	}
+
+	log_buf = va_arg(args, char *);
+	if (!log_buf)
+		goto out;
+	if (err_str && strstr(log_buf, err_str) != NULL)
+		found = true;
+out:
+	printf(format, log_buf);
+	return 0;
+}
+
+static void test_invalid_license(void)
+{
+	libbpf_print_fn_t old_print_fn;
+	struct bpf_tcp_nogpl *skel;
+
+	err_str = "struct ops programs must have a GPL compatible license";
+	found = false;
+	old_print_fn = libbpf_set_print(libbpf_debug_print);
+
+	skel = bpf_tcp_nogpl__open_and_load();
+	ASSERT_NULL(skel, "bpf_tcp_nogpl");
+	ASSERT_EQ(found, true, "expected_err_msg");
+
+	bpf_tcp_nogpl__destroy(skel);
+	libbpf_set_print(old_print_fn);
+}
+
 void test_bpf_tcp_ca(void)
 {
 	if (test__start_subtest("dctcp"))
 		test_dctcp();
 	if (test__start_subtest("cubic"))
 		test_cubic();
+	if (test__start_subtest("invalid_license"))
+		test_invalid_license();
 }

tools/testing/selftests/bpf/progs/bpf_tcp_nogpl.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <linux/types.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "bpf_tcp_helpers.h"
+
+char _license[] SEC("license") = "X";
+
+void BPF_STRUCT_OPS(nogpltcp_init, struct sock *sk)
+{
+}
+
+SEC(".struct_ops")
+struct tcp_congestion_ops bpf_nogpltcp = {
+	.init           = (void *)nogpltcp_init,
+	.name           = "bpf_nogpltcp",
+};