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 <davem@davemloft.net>

4 files changed, 25 insertions, 20 deletions

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 49b1a70e12c8..212991f6f2a5 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -160,6 +160,7 @@ static inline void copy_map_value(struct bpf_map *map, void *dst, void *src)
 }
 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;
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 32ab9225026e..7787bdcb5d68 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -4564,7 +4564,7 @@ int btf_get_info_by_fd(const struct btf *btf,
 		       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;
@@ -4573,6 +4573,7 @@ int btf_get_info_by_fd(const struct btf *btf,
 	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;
 
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 0c7fb0d4836d..966b7b34cde0 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -696,14 +696,15 @@ int bpf_get_file_flag(int flags)
 		   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) &&
@@ -712,11 +713,11 @@ static int bpf_obj_name_cpy(char *dst, const char *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,
@@ -810,8 +811,9 @@ static int map_create(union bpf_attr *attr)
 	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);
@@ -2098,8 +2100,9 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
 		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 */
@@ -2792,7 +2795,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
 				   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;
@@ -2804,6 +2807,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
 		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;
 
@@ -3067,7 +3071,7 @@ static int bpf_map_get_info_by_fd(struct bpf_map *map,
 				  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;
 
@@ -3076,6 +3080,7 @@ static int bpf_map_get_info_by_fd(struct bpf_map *map,
 		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;
@@ -3359,7 +3364,7 @@ err_put:
 
 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))
@@ -3371,6 +3376,7 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
 	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;
 
diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c
index 574972bc7299..2bf3abeb1456 100644
--- a/net/ipv4/bpf_tcp_ca.c
+++ b/net/ipv4/bpf_tcp_ca.c
@@ -184,7 +184,6 @@ static int bpf_tcp_ca_init_member(const struct btf_type *t,
 {
 	const struct tcp_congestion_ops *utcp_ca;
 	struct tcp_congestion_ops *tcp_ca;
-	size_t tcp_ca_name_len;
 	int prog_fd;
 	u32 moff;
 
@@ -199,13 +198,11 @@ static int bpf_tcp_ca_init_member(const struct btf_type *t,
 		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;
 	}