Commit 755662ce authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

af_unix: Use offsetof() instead of sizeof(). 



The length of the AF_UNIX socket address contains an offset to the member
sun_path of struct sockaddr_un.

Currently, the preceding member is just sun_family, and its type is
sa_family_t and resolved to short.  Therefore, the offset is represented by
sizeof(short).  However, it is not clear and fragile to changes in struct
sockaddr_storage or sockaddr_un.

This commit makes it clear and robust by rewriting sizeof() with
offsetof().

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 442b03c3

net/unix/af_unix.c

+12 −7
Original line number Diff line number Diff line
@@ -231,7 +231,8 @@ static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp 
{

	*hashp = 0;



	if (len <= sizeof(short) || len > sizeof(*sunaddr))

	if (len <= offsetof(struct sockaddr_un, sun_path) ||

	    len > sizeof(*sunaddr))

		return -EINVAL;

	if (!sunaddr || sunaddr->sun_family != AF_UNIX)

		return -EINVAL;
@@ -244,7 +245,8 @@ static int unix_mkname(struct sockaddr_un *sunaddr, int len, unsigned int *hashp 
		 * kernel address buffer.

		 */

		((char *)sunaddr)[len] = 0;

		len = strlen(sunaddr->sun_path)+1+sizeof(short);

		len = strlen(sunaddr->sun_path) +

			offsetof(struct sockaddr_un, sun_path) + 1;

		return len;

	}
@@ -966,7 +968,8 @@ static int unix_autobind(struct socket *sock) 
		goto out;



	err = -ENOMEM;

	addr = kzalloc(sizeof(*addr) + sizeof(short) + 16, GFP_KERNEL);

	addr = kzalloc(sizeof(*addr) +

		       offsetof(struct sockaddr_un, sun_path) + 16, GFP_KERNEL);

	if (!addr)

		goto out;
@@ -974,7 +977,8 @@ static int unix_autobind(struct socket *sock) 
	refcount_set(&addr->refcnt, 1);



retry:

	addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);

	addr->len = sprintf(addr->name->sun_path + 1, "%05x", ordernum) +

		offsetof(struct sockaddr_un, sun_path) + 1;

	addr->hash = unix_hash_fold(csum_partial(addr->name, addr->len, 0));

	addr->hash ^= sk->sk_type;
@@ -1156,7 +1160,7 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) 
	    sunaddr->sun_family != AF_UNIX)

		return -EINVAL;



	if (addr_len == sizeof(short))

	if (addr_len == offsetof(struct sockaddr_un, sun_path))

		return unix_autobind(sock);



	err = unix_mkname(sunaddr, addr_len, &hash);
@@ -1600,7 +1604,7 @@ static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer) 
	if (!addr) {

		sunaddr->sun_family = AF_UNIX;

		sunaddr->sun_path[0] = 0;

		err = sizeof(short);

		err = offsetof(struct sockaddr_un, sun_path);

	} else {

		err = addr->len;

		memcpy(sunaddr, addr->name, addr->len);
@@ -3228,7 +3232,8 @@ static int unix_seq_show(struct seq_file *seq, void *v) 
			seq_putc(seq, ' ');



			i = 0;

			len = u->addr->len - sizeof(short);

			len = u->addr->len -

				offsetof(struct sockaddr_un, sun_path);

			if (!UNIX_ABSTRACT(s))

				len--;

			else {

net/unix/diag.c

+2 −1
Original line number Diff line number Diff line
@@ -19,7 +19,8 @@ static int sk_diag_dump_name(struct sock *sk, struct sk_buff *nlskb) 
	if (!addr)

		return 0;



	return nla_put(nlskb, UNIX_DIAG_NAME, addr->len - sizeof(short),

	return nla_put(nlskb, UNIX_DIAG_NAME,

		       addr->len - offsetof(struct sockaddr_un, sun_path),

		       addr->name->sun_path);

}