libceph: fix unaligned accesses in ceph_entity_addr handling [Linux 5.2]

libceph: fix unaligned accesses in ceph_entity_addr handling [Linux 5.2]

This Linux kernel change "libceph: fix unaligned accesses in ceph_entity_addr handling" is included in the Linux 5.2 release. This change is authored by Jeff Layton <jlayton [at] kernel.org> on Mon May 6 09:38:46 2019 -0400. The commit for this change in Linux stable tree is cede185 (patch).

libceph: fix unaligned accesses in ceph_entity_addr handling

GCC9 is throwing a lot of warnings about unaligned access. This patch
fixes some of them by changing most of the sockaddr handling functions
to take a pointer to struct ceph_entity_addr instead of struct
sockaddr_storage.  The lower functions can then make copies or do
unaligned accesses as needed.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

There are 77 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 net/ceph/messenger.c | 77 +++++++++++++++++++++++++---------------------------
 1 file changed, 37 insertions(+), 40 deletions(-)

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 3083988..3e0cc98 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -449,7 +449,7 @@ static void set_sock_callbacks(struct socket *sock,
  */
 static int ceph_tcp_connect(struct ceph_connection *con)
 {
-   struct sockaddr_storage *paddr = &con->peer_addr.in_addr;
+   struct sockaddr_storage ss = con->peer_addr.in_addr; /* align */
    struct socket *sock;
    unsigned int noio_flag;
    int ret;
@@ -458,7 +458,7 @@ static int ceph_tcp_connect(struct ceph_connection *con)

    /* sock_create_kern() allocates with GFP_KERNEL */
    noio_flag = memalloc_noio_save();
-   ret = sock_create_kern(read_pnet(&con->msgr->net), paddr->ss_family,
+   ret = sock_create_kern(read_pnet(&con->msgr->net), ss.ss_family,
                   SOCK_STREAM, IPPROTO_TCP, &sock);
    memalloc_noio_restore(noio_flag);
    if (ret)
@@ -474,7 +474,7 @@ static int ceph_tcp_connect(struct ceph_connection *con)
    dout("connect %s\n", ceph_pr_addr(&con->peer_addr.in_addr));

    con_sock_state_connecting(con);
-   ret = sock->ops->connect(sock, (struct sockaddr *)paddr, sizeof(*paddr),
+   ret = sock->ops->connect(sock, (struct sockaddr *)&ss, sizeof(ss),
                 O_NONBLOCK);
    if (ret == -EINPROGRESS) {
        dout("connect %s EINPROGRESS sk_state = %u\n",
@@ -1795,14 +1795,15 @@ static int verify_hello(struct ceph_connection *con)
    return 0;
 }

-static bool addr_is_blank(struct sockaddr_storage *ss)
+static bool addr_is_blank(struct ceph_entity_addr *addr)
 {
-   struct in_addr *addr = &((struct sockaddr_in *)ss)->sin_addr;
-   struct in6_addr *addr6 = &((struct sockaddr_in6 *)ss)->sin6_addr;
+   struct sockaddr_storage ss = addr->in_addr; /* align */
+   struct in_addr *addr4 = &((struct sockaddr_in *)&ss)->sin_addr;
+   struct in6_addr *addr6 = &((struct sockaddr_in6 *)&ss)->sin6_addr;

-   switch (ss->ss_family) {
+   switch (ss.ss_family) {
    case AF_INET:
-       return addr->s_addr == htonl(INADDR_ANY);
+       return addr4->s_addr == htonl(INADDR_ANY);
    case AF_INET6:
        return ipv6_addr_any(addr6);
    default:
@@ -1810,25 +1811,25 @@ static bool addr_is_blank(struct sockaddr_storage *ss)
    }
 }

-static int addr_port(struct sockaddr_storage *ss)
+static int addr_port(struct ceph_entity_addr *addr)
 {
-   switch (ss->ss_family) {
+   switch (get_unaligned(&addr->in_addr.ss_family)) {
    case AF_INET:
-       return ntohs(((struct sockaddr_in *)ss)->sin_port);
+       return ntohs(get_unaligned(&((struct sockaddr_in *)&addr->in_addr)->sin_port));
    case AF_INET6:
-       return ntohs(((struct sockaddr_in6 *)ss)->sin6_port);
+       return ntohs(get_unaligned(&((struct sockaddr_in6 *)&addr->in_addr)->sin6_port));
    }
    return 0;
 }

-static void addr_set_port(struct sockaddr_storage *ss, int p)
+static void addr_set_port(struct ceph_entity_addr *addr, int p)
 {
-   switch (ss->ss_family) {
+   switch (get_unaligned(&addr->in_addr.ss_family)) {
    case AF_INET:
-       ((struct sockaddr_in *)ss)->sin_port = htons(p);
+       put_unaligned(htons(p), &((struct sockaddr_in *)&addr->in_addr)->sin_port);
        break;
    case AF_INET6:
-       ((struct sockaddr_in6 *)ss)->sin6_port = htons(p);
+       put_unaligned(htons(p), &((struct sockaddr_in6 *)&addr->in_addr)->sin6_port);
        break;
    }
 }
@@ -1836,21 +1837,18 @@ static void addr_set_port(struct sockaddr_storage *ss, int p)
 /*
  * Unlike other *_pton function semantics, zero indicates success.
  */
-static int ceph_pton(const char *str, size_t len, struct sockaddr_storage *ss,
+static int ceph_pton(const char *str, size_t len, struct ceph_entity_addr *addr,
        char delim, const char **ipend)
 {
-   struct sockaddr_in *in4 = (struct sockaddr_in *) ss;
-   struct sockaddr_in6 *in6 = (struct sockaddr_in6 *) ss;
-
-   memset(ss, 0, sizeof(*ss));
+   memset(&addr->in_addr, 0, sizeof(addr->in_addr));

-   if (in4_pton(str, len, (u8 *)&in4->sin_addr.s_addr, delim, ipend)) {
-       ss->ss_family = AF_INET;
+   if (in4_pton(str, len, (u8 *)&((struct sockaddr_in *)&addr->in_addr)->sin_addr.s_addr, delim, ipend)) {
+       put_unaligned(AF_INET, &addr->in_addr.ss_family);
        return 0;
    }

-   if (in6_pton(str, len, (u8 *)&in6->sin6_addr.s6_addr, delim, ipend)) {
-       ss->ss_family = AF_INET6;
+   if (in6_pton(str, len, (u8 *)&((struct sockaddr_in6 *)&addr->in_addr)->sin6_addr.s6_addr, delim, ipend)) {
+       put_unaligned(AF_INET6, &addr->in_addr.ss_family);
        return 0;
    }

@@ -1862,7 +1860,7 @@ static int ceph_pton(const char *str, size_t len, struct sockaddr_storage *ss,
  */
 #ifdef CONFIG_CEPH_LIB_USE_DNS_RESOLVER
 static int ceph_dns_resolve_name(const char *name, size_t namelen,
-       struct sockaddr_storage *ss, char delim, const char **ipend)
+       struct ceph_entity_addr *addr, char delim, const char **ipend)
 {
    const char *end, *delim_p;
    char *colon_p, *ip_addr = NULL;
@@ -1891,7 +1889,7 @@ static int ceph_dns_resolve_name(const char *name, size_t namelen,
    /* do dns_resolve upcall */
    ip_len = dns_query(NULL, name, end - name, NULL, &ip_addr, NULL);
    if (ip_len > 0)
-       ret = ceph_pton(ip_addr, ip_len, ss, -1, NULL);
+       ret = ceph_pton(ip_addr, ip_len, addr, -1, NULL);
    else
        ret = -ESRCH;

@@ -1900,13 +1898,13 @@ static int ceph_dns_resolve_name(const char *name, size_t namelen,
    *ipend = end;

    pr_info("resolve '%.*s' (ret=%d): %s\n", (int)(end - name), name,
-           ret, ret ? "failed" : ceph_pr_addr(ss));
+           ret, ret ? "failed" : ceph_pr_addr(&addr->in_addr));

    return ret;
 }
 #else
 static inline int ceph_dns_resolve_name(const char *name, size_t namelen,
-       struct sockaddr_storage *ss, char delim, const char **ipend)
+       struct ceph_entity_addr *addr, char delim, const char **ipend)
 {
    return -EINVAL;
 }
@@ -1917,13 +1915,13 @@ static inline int ceph_dns_resolve_name(const char *name, size_t namelen,
  * then try to extract a hostname to resolve using userspace DNS upcall.
  */
 static int ceph_parse_server_name(const char *name, size_t namelen,
-           struct sockaddr_storage *ss, char delim, const char **ipend)
+       struct ceph_entity_addr *addr, char delim, const char **ipend)
 {
    int ret;

-   ret = ceph_pton(name, namelen, ss, delim, ipend);
+   ret = ceph_pton(name, namelen, addr, delim, ipend);
    if (ret)
-       ret = ceph_dns_resolve_name(name, namelen, ss, delim, ipend);
+       ret = ceph_dns_resolve_name(name, namelen, addr, delim, ipend);

    return ret;
 }
@@ -1942,7 +1940,6 @@ int ceph_parse_ips(const char *c, const char *end,
    dout("parse_ips on '%.*s'\n", (int)(end-c), c);
    for (i = 0; i < max_count; i++) {
        const char *ipend;
-       struct sockaddr_storage *ss = &addr[i].in_addr;
        int port;
        char delim = ',';

@@ -1951,7 +1948,7 @@ int ceph_parse_ips(const char *c, const char *end,
            p++;
        }

-       ret = ceph_parse_server_name(p, end - p, ss, delim, &ipend);
+       ret = ceph_parse_server_name(p, end - p, &addr[i], delim, &ipend);
        if (ret)
            goto bad;
        ret = -EINVAL;
@@ -1982,9 +1979,9 @@ int ceph_parse_ips(const char *c, const char *end,
            port = CEPH_MON_PORT;
        }

-       addr_set_port(ss, port);
+       addr_set_port(&addr[i], port);

-       dout("parse_ips got %s\n", ceph_pr_addr(ss));
+       dout("parse_ips got %s\n", ceph_pr_addr(&addr[i].in_addr));

        if (p == end)
            break;
@@ -2023,7 +2020,7 @@ static int process_banner(struct ceph_connection *con)
     */
    if (memcmp(&con->peer_addr, &con->actual_peer_addr,
           sizeof(con->peer_addr)) != 0 &&
-       !(addr_is_blank(&con->actual_peer_addr.in_addr) &&
+       !(addr_is_blank(&con->actual_peer_addr) &&
          con->actual_peer_addr.nonce == con->peer_addr.nonce)) {
        pr_warn("wrong peer, want %s/%d, got %s/%d\n",
            ceph_pr_addr(&con->peer_addr.in_addr),
@@ -2037,13 +2034,13 @@ static int process_banner(struct ceph_connection *con)
    /*
     * did we learn our address?
     */
-   if (addr_is_blank(&con->msgr->inst.addr.in_addr)) {
-       int port = addr_port(&con->msgr->inst.addr.in_addr);
+   if (addr_is_blank(&con->msgr->inst.addr)) {
+       int port = addr_port(&con->msgr->inst.addr);

        memcpy(&con->msgr->inst.addr.in_addr,
               &con->peer_addr_for_me.in_addr,
               sizeof(con->peer_addr_for_me.in_addr));
-       addr_set_port(&con->msgr->inst.addr.in_addr, port);
+       addr_set_port(&con->msgr->inst.addr, port);
        encode_my_addr(con->msgr);
        dout("process_banner learned my addr is %s\n",
             ceph_pr_addr(&con->msgr->inst.addr.in_addr));

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