From 755662ce78d14c1a9118df921c528b1f992ded2e Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Wed, 24 Nov 2021 11:14:19 +0900 Subject: 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: Kuniyuki Iwashima Signed-off-by: Jakub Kicinski --- net/unix/af_unix.c | 19 ++++++++++++------- net/unix/diag.c | 3 ++- 2 files changed, 14 insertions(+), 8 deletions(-) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index b9ff1f31f3af..31c085e3c1fa 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -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 { diff --git a/net/unix/diag.c b/net/unix/diag.c index 7e7d7f45685a..db555f267407 100644 --- a/net/unix/diag.c +++ b/net/unix/diag.c @@ -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); } -- cgit v1.2.3-59-g8ed1b