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

Daniel Borkmann says:

====================
pull-request: bpf 2020-03-27

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

We've added 3 non-merge commits during the last 4 day(s) which contain
a total of 4 files changed, 25 insertions(+), 20 deletions(-).

The main changes are:

1) Explicitly memset the bpf_attr structure on bpf() syscall to avoid
having to rely on compiler to do so. Issues have been noticed on
some compilers with padding and other oddities where the request was
then unexpectedly rejected, from Greg Kroah-Hartman.

2) Sanitize the bpf_struct_ops TCP congestion control name in order to
avoid problematic characters such as whitespaces, from Martin KaFai Lau.
====================

Signed-off-by: David S. Miller <[e-mail]>

include/linux/bpf.h

···
 }
 void copy_map_value_locked(struct bpf_map *map, void *dst, void *src,
 			   bool lock_src);
+int bpf_obj_name_cpy(char *dst, const char *src, unsigned int size);
 
 struct bpf_offload_dev;
 struct bpf_offloaded_map;

kernel/bpf/btf.c

···
 		       union bpf_attr __user *uattr)
 {
 	struct bpf_btf_info __user *uinfo;
-	struct bpf_btf_info info = {};
+	struct bpf_btf_info info;
 	u32 info_copy, btf_copy;
 	void __user *ubtf;
 	u32 uinfo_len;
···
 	uinfo_len = attr->info.info_len;
 
 	info_copy = min_t(u32, uinfo_len, sizeof(info));
+	memset(&info, 0, sizeof(info));
 	if (copy_from_user(&info, uinfo, info_copy))
 		return -EFAULT;
 

kernel/bpf/syscall.c

···
 		   offsetof(union bpf_attr, CMD##_LAST_FIELD) - \
 		   sizeof(attr->CMD##_LAST_FIELD)) != NULL
 
-/* dst and src must have at least BPF_OBJ_NAME_LEN number of bytes.
- * Return 0 on success and < 0 on error.
+/* dst and src must have at least "size" number of bytes.
+ * Return strlen on success and < 0 on error.
  */
-static int bpf_obj_name_cpy(char *dst, const char *src)
+int bpf_obj_name_cpy(char *dst, const char *src, unsigned int size)
 {
-	const char *end = src + BPF_OBJ_NAME_LEN;
+	const char *end = src + size;
+	const char *orig_src = src;
 
-	memset(dst, 0, BPF_OBJ_NAME_LEN);
+	memset(dst, 0, size);
 	/* Copy all isalnum(), '_' and '.' chars. */
 	while (src < end && *src) {
 		if (!isalnum(*src) &&
···
 		*dst++ = *src++;
 	}
 
-	/* No '\0' found in BPF_OBJ_NAME_LEN number of bytes */
+	/* No '\0' found in "size" number of bytes */
 	if (src == end)
 		return -EINVAL;
 
-	return 0;
+	return src - orig_src;
 }
 
 int map_check_no_btf(const struct bpf_map *map,
···
 	if (IS_ERR(map))
 		return PTR_ERR(map);
 
-	err = bpf_obj_name_cpy(map->name, attr->map_name);
-	if (err)
+	err = bpf_obj_name_cpy(map->name, attr->map_name,
+			       sizeof(attr->map_name));
+	if (err < 0)
 		goto free_map;
 
 	atomic64_set(&map->refcnt, 1);
···
 		goto free_prog;
 
 	prog->aux->load_time = ktime_get_boottime_ns();
-	err = bpf_obj_name_cpy(prog->aux->name, attr->prog_name);
-	if (err)
+	err = bpf_obj_name_cpy(prog->aux->name, attr->prog_name,
+			       sizeof(attr->prog_name));
+	if (err < 0)
 		goto free_prog;
 
 	/* run eBPF verifier */
···
 				   union bpf_attr __user *uattr)
 {
 	struct bpf_prog_info __user *uinfo = u64_to_user_ptr(attr->info.info);
-	struct bpf_prog_info info = {};
+	struct bpf_prog_info info;
 	u32 info_len = attr->info.info_len;
 	struct bpf_prog_stats stats;
 	char __user *uinsns;
···
 		return err;
 	info_len = min_t(u32, sizeof(info), info_len);
 
+	memset(&info, 0, sizeof(info));
 	if (copy_from_user(&info, uinfo, info_len))
 		return -EFAULT;
 
···
 				  union bpf_attr __user *uattr)
 {
 	struct bpf_map_info __user *uinfo = u64_to_user_ptr(attr->info.info);
-	struct bpf_map_info info = {};
+	struct bpf_map_info info;
 	u32 info_len = attr->info.info_len;
 	int err;
 
···
 		return err;
 	info_len = min_t(u32, sizeof(info), info_len);
 
+	memset(&info, 0, sizeof(info));
 	info.type = map->map_type;
 	info.id = map->id;
 	info.key_size = map->key_size;
···
 
 SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size)
 {
-	union bpf_attr attr = {};
+	union bpf_attr attr;
 	int err;
 
 	if (sysctl_unprivileged_bpf_disabled && !capable(CAP_SYS_ADMIN))
···
 	size = min_t(u32, size, sizeof(attr));
 
 	/* copy attributes from user space, may be less than sizeof(bpf_attr) */
+	memset(&attr, 0, sizeof(attr));
 	if (copy_from_user(&attr, uattr, size) != 0)
 		return -EFAULT;
 

net/ipv4/bpf_tcp_ca.c

···
 {
 	const struct tcp_congestion_ops *utcp_ca;
 	struct tcp_congestion_ops *tcp_ca;
-	size_t tcp_ca_name_len;
 	int prog_fd;
 	u32 moff;
 
···
 		tcp_ca->flags = utcp_ca->flags;
 		return 1;
 	case offsetof(struct tcp_congestion_ops, name):
-		tcp_ca_name_len = strnlen(utcp_ca->name, sizeof(utcp_ca->name));
-		if (!tcp_ca_name_len ||
-		    tcp_ca_name_len == sizeof(utcp_ca->name))
+		if (bpf_obj_name_cpy(tcp_ca->name, utcp_ca->name,
+				     sizeof(tcp_ca->name)) <= 0)
 			return -EINVAL;
 		if (tcp_ca_find(utcp_ca->name))
 			return -EEXIST;
-		memcpy(tcp_ca->name, utcp_ca->name, sizeof(tcp_ca->name));
 		return 1;
 	}