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

Daniel Borkmann says:

====================
pull-request: bpf 2019-05-13

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

The main changes are:

1) Fix out of bounds backwards jumps due to a bug in dead code
   removal, from Daniel.

2) Fix libbpf users by detecting unsupported BTF kernel features
   and sanitize them before load, from Andrii.

3) Fix undefined behavior in narrow load handling of context
   fields, from Krzesimir.

4) Various BPF uapi header doc/man page fixes, from Quentin.

5) Misc .gitignore fixups to exclude built files, from Kelsey.
====================

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

1 files changed, 41 insertions, 32 deletions

diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c
index a2c64a9ce1a6..5e2aa83f637a 100644
--- a/tools/lib/bpf/libbpf_probes.c
+++ b/tools/lib/bpf/libbpf_probes.c
@@ -15,6 +15,7 @@
 
 #include "bpf.h"
 #include "libbpf.h"
+#include "libbpf_internal.h"
 
 static bool grep(const char *buffer, const char *pattern)
 {
@@ -132,21 +133,43 @@ bool bpf_probe_prog_type(enum bpf_prog_type prog_type, __u32 ifindex)
 	return errno != EINVAL && errno != EOPNOTSUPP;
 }
 
-static int load_btf(void)
+int libbpf__probe_raw_btf(const char *raw_types, size_t types_len,
+			  const char *str_sec, size_t str_len)
 {
-#define BTF_INFO_ENC(kind, kind_flag, vlen) \
-	((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
-#define BTF_TYPE_ENC(name, info, size_or_type) \
-	(name), (info), (size_or_type)
-#define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
-	((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
-#define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
-	BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
-	BTF_INT_ENC(encoding, bits_offset, bits)
-#define BTF_MEMBER_ENC(name, type, bits_offset) \
-	(name), (type), (bits_offset)
-
-	const char btf_str_sec[] = "\0bpf_spin_lock\0val\0cnt\0l";
+	struct btf_header hdr = {
+		.magic = BTF_MAGIC,
+		.version = BTF_VERSION,
+		.hdr_len = sizeof(struct btf_header),
+		.type_len = types_len,
+		.str_off = types_len,
+		.str_len = str_len,
+	};
+	int btf_fd, btf_len;
+	__u8 *raw_btf;
+
+	btf_len = hdr.hdr_len + hdr.type_len + hdr.str_len;
+	raw_btf = malloc(btf_len);
+	if (!raw_btf)
+		return -ENOMEM;
+
+	memcpy(raw_btf, &hdr, sizeof(hdr));
+	memcpy(raw_btf + hdr.hdr_len, raw_types, hdr.type_len);
+	memcpy(raw_btf + hdr.hdr_len + hdr.type_len, str_sec, hdr.str_len);
+
+	btf_fd = bpf_load_btf(raw_btf, btf_len, NULL, 0, false);
+	if (btf_fd < 0) {
+		free(raw_btf);
+		return 0;
+	}
+
+	close(btf_fd);
+	free(raw_btf);
+	return 1;
+}
+
+static int load_sk_storage_btf(void)
+{
+	const char strs[] = "\0bpf_spin_lock\0val\0cnt\0l";
 	/* struct bpf_spin_lock {
 	 *   int val;
 	 * };
@@ -155,7 +178,7 @@ static int load_btf(void)
 	 *   struct bpf_spin_lock l;
 	 * };
 	 */
-	__u32 btf_raw_types[] = {
+	__u32 types[] = {
 		/* int */
 		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
 		/* struct bpf_spin_lock */                      /* [2] */
@@ -166,23 +189,9 @@ static int load_btf(void)
 		BTF_MEMBER_ENC(19, 1, 0), /* int cnt; */
 		BTF_MEMBER_ENC(23, 2, 32),/* struct bpf_spin_lock l; */
 	};
-	struct btf_header btf_hdr = {
-		.magic = BTF_MAGIC,
-		.version = BTF_VERSION,
-		.hdr_len = sizeof(struct btf_header),
-		.type_len = sizeof(btf_raw_types),
-		.str_off = sizeof(btf_raw_types),
-		.str_len = sizeof(btf_str_sec),
-	};
-	__u8 raw_btf[sizeof(struct btf_header) + sizeof(btf_raw_types) +
-		     sizeof(btf_str_sec)];
-
-	memcpy(raw_btf, &btf_hdr, sizeof(btf_hdr));
-	memcpy(raw_btf + sizeof(btf_hdr), btf_raw_types, sizeof(btf_raw_types));
-	memcpy(raw_btf + sizeof(btf_hdr) + sizeof(btf_raw_types),
-	       btf_str_sec, sizeof(btf_str_sec));
 
-	return bpf_load_btf(raw_btf, sizeof(raw_btf), 0, 0, 0);
+	return libbpf__probe_raw_btf((char *)types, sizeof(types),
+				     strs, sizeof(strs));
 }
 
 bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex)
@@ -222,7 +231,7 @@ bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex)
 		value_size = 8;
 		max_entries = 0;
 		map_flags = BPF_F_NO_PREALLOC;
-		btf_fd = load_btf();
+		btf_fd = load_sk_storage_btf();
 		if (btf_fd < 0)
 			return false;
 		break;