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authorMatt Johnston <matt@codeconstruct.com.au>2022-02-09 07:05:57 +0300
committerDavid S. Miller <davem@davemloft.net>2022-02-09 15:00:11 +0300
commit63ed1aab3d40aa61aaa66819bdce9377ac7f40fa (patch)
tree6f239012c2653e6f0d89ef1ac483467e2590a339 /net/mctp/af_mctp.c
parent0de55a7d1133d0ab1acad5d91eea6ccd8cf6d448 (diff)
downloadlinux-63ed1aab3d40aa61aaa66819bdce9377ac7f40fa.tar.xz
mctp: Add SIOCMCTP{ALLOC,DROP}TAG ioctls for tag control
This change adds a couple of new ioctls for mctp sockets: SIOCMCTPALLOCTAG and SIOCMCTPDROPTAG. These ioctls provide facilities for explicit allocation / release of tags, overriding the automatic allocate-on-send/release-on-reply and timeout behaviours. This allows userspace more control over messages that may not fit a simple request/response model. In order to indicate a pre-allocated tag to the sendmsg() syscall, we introduce a new flag to the struct sockaddr_mctp.smctp_tag value: MCTP_TAG_PREALLOC. Additional changes from Jeremy Kerr <jk@codeconstruct.com.au>. Contains a fix that was: Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Matt Johnston <matt@codeconstruct.com.au> Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/mctp/af_mctp.c')
-rw-r--r--net/mctp/af_mctp.c189
1 files changed, 163 insertions, 26 deletions
diff --git a/net/mctp/af_mctp.c b/net/mctp/af_mctp.c
index c921de63b494..f0702d920d8d 100644
--- a/net/mctp/af_mctp.c
+++ b/net/mctp/af_mctp.c
@@ -6,6 +6,7 @@
* Copyright (c) 2021 Google
*/
+#include <linux/compat.h>
#include <linux/if_arp.h>
#include <linux/net.h>
#include <linux/mctp.h>
@@ -21,6 +22,8 @@
/* socket implementation */
+static void mctp_sk_expire_keys(struct timer_list *timer);
+
static int mctp_release(struct socket *sock)
{
struct sock *sk = sock->sk;
@@ -99,13 +102,20 @@ static int mctp_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
struct sk_buff *skb;
if (addr) {
+ const u8 tagbits = MCTP_TAG_MASK | MCTP_TAG_OWNER |
+ MCTP_TAG_PREALLOC;
+
if (addrlen < sizeof(struct sockaddr_mctp))
return -EINVAL;
if (addr->smctp_family != AF_MCTP)
return -EINVAL;
if (!mctp_sockaddr_is_ok(addr))
return -EINVAL;
- if (addr->smctp_tag & ~(MCTP_TAG_MASK | MCTP_TAG_OWNER))
+ if (addr->smctp_tag & ~tagbits)
+ return -EINVAL;
+ /* can't preallocate a non-owned tag */
+ if (addr->smctp_tag & MCTP_TAG_PREALLOC &&
+ !(addr->smctp_tag & MCTP_TAG_OWNER))
return -EINVAL;
} else {
@@ -248,6 +258,32 @@ out_free:
return rc;
}
+/* We're done with the key; invalidate, stop reassembly, and remove from lists.
+ */
+static void __mctp_key_remove(struct mctp_sk_key *key, struct net *net,
+ unsigned long flags, unsigned long reason)
+__releases(&key->lock)
+__must_hold(&net->mctp.keys_lock)
+{
+ struct sk_buff *skb;
+
+ trace_mctp_key_release(key, reason);
+ skb = key->reasm_head;
+ key->reasm_head = NULL;
+ key->reasm_dead = true;
+ key->valid = false;
+ mctp_dev_release_key(key->dev, key);
+ spin_unlock_irqrestore(&key->lock, flags);
+
+ hlist_del(&key->hlist);
+ hlist_del(&key->sklist);
+
+ /* unref for the lists */
+ mctp_key_unref(key);
+
+ kfree_skb(skb);
+}
+
static int mctp_setsockopt(struct socket *sock, int level, int optname,
sockptr_t optval, unsigned int optlen)
{
@@ -293,6 +329,115 @@ static int mctp_getsockopt(struct socket *sock, int level, int optname,
return -EINVAL;
}
+static int mctp_ioctl_alloctag(struct mctp_sock *msk, unsigned long arg)
+{
+ struct net *net = sock_net(&msk->sk);
+ struct mctp_sk_key *key = NULL;
+ struct mctp_ioc_tag_ctl ctl;
+ unsigned long flags;
+ u8 tag;
+
+ if (copy_from_user(&ctl, (void __user *)arg, sizeof(ctl)))
+ return -EFAULT;
+
+ if (ctl.tag)
+ return -EINVAL;
+
+ if (ctl.flags)
+ return -EINVAL;
+
+ key = mctp_alloc_local_tag(msk, ctl.peer_addr, MCTP_ADDR_ANY,
+ true, &tag);
+ if (IS_ERR(key))
+ return PTR_ERR(key);
+
+ ctl.tag = tag | MCTP_TAG_OWNER | MCTP_TAG_PREALLOC;
+ if (copy_to_user((void __user *)arg, &ctl, sizeof(ctl))) {
+ spin_lock_irqsave(&key->lock, flags);
+ __mctp_key_remove(key, net, flags, MCTP_TRACE_KEY_DROPPED);
+ mctp_key_unref(key);
+ return -EFAULT;
+ }
+
+ mctp_key_unref(key);
+ return 0;
+}
+
+static int mctp_ioctl_droptag(struct mctp_sock *msk, unsigned long arg)
+{
+ struct net *net = sock_net(&msk->sk);
+ struct mctp_ioc_tag_ctl ctl;
+ unsigned long flags, fl2;
+ struct mctp_sk_key *key;
+ struct hlist_node *tmp;
+ int rc;
+ u8 tag;
+
+ if (copy_from_user(&ctl, (void __user *)arg, sizeof(ctl)))
+ return -EFAULT;
+
+ if (ctl.flags)
+ return -EINVAL;
+
+ /* Must be a local tag, TO set, preallocated */
+ if ((ctl.tag & ~MCTP_TAG_MASK) != (MCTP_TAG_OWNER | MCTP_TAG_PREALLOC))
+ return -EINVAL;
+
+ tag = ctl.tag & MCTP_TAG_MASK;
+ rc = -EINVAL;
+
+ spin_lock_irqsave(&net->mctp.keys_lock, flags);
+ hlist_for_each_entry_safe(key, tmp, &msk->keys, sklist) {
+ /* we do an irqsave here, even though we know the irq state,
+ * so we have the flags to pass to __mctp_key_remove
+ */
+ spin_lock_irqsave(&key->lock, fl2);
+ if (key->manual_alloc &&
+ ctl.peer_addr == key->peer_addr &&
+ tag == key->tag) {
+ __mctp_key_remove(key, net, fl2,
+ MCTP_TRACE_KEY_DROPPED);
+ rc = 0;
+ } else {
+ spin_unlock_irqrestore(&key->lock, fl2);
+ }
+ }
+ spin_unlock_irqrestore(&net->mctp.keys_lock, flags);
+
+ return rc;
+}
+
+static int mctp_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+ struct mctp_sock *msk = container_of(sock->sk, struct mctp_sock, sk);
+
+ switch (cmd) {
+ case SIOCMCTPALLOCTAG:
+ return mctp_ioctl_alloctag(msk, arg);
+ case SIOCMCTPDROPTAG:
+ return mctp_ioctl_droptag(msk, arg);
+ }
+
+ return -EINVAL;
+}
+
+#ifdef CONFIG_COMPAT
+static int mctp_compat_ioctl(struct socket *sock, unsigned int cmd,
+ unsigned long arg)
+{
+ void __user *argp = compat_ptr(arg);
+
+ switch (cmd) {
+ /* These have compatible ptr layouts */
+ case SIOCMCTPALLOCTAG:
+ case SIOCMCTPDROPTAG:
+ return mctp_ioctl(sock, cmd, (unsigned long)argp);
+ }
+
+ return -ENOIOCTLCMD;
+}
+#endif
+
static const struct proto_ops mctp_dgram_ops = {
.family = PF_MCTP,
.release = mctp_release,
@@ -302,7 +447,7 @@ static const struct proto_ops mctp_dgram_ops = {
.accept = sock_no_accept,
.getname = sock_no_getname,
.poll = datagram_poll,
- .ioctl = sock_no_ioctl,
+ .ioctl = mctp_ioctl,
.gettstamp = sock_gettstamp,
.listen = sock_no_listen,
.shutdown = sock_no_shutdown,
@@ -312,6 +457,9 @@ static const struct proto_ops mctp_dgram_ops = {
.recvmsg = mctp_recvmsg,
.mmap = sock_no_mmap,
.sendpage = sock_no_sendpage,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = mctp_compat_ioctl,
+#endif
};
static void mctp_sk_expire_keys(struct timer_list *timer)
@@ -319,7 +467,7 @@ static void mctp_sk_expire_keys(struct timer_list *timer)
struct mctp_sock *msk = container_of(timer, struct mctp_sock,
key_expiry);
struct net *net = sock_net(&msk->sk);
- unsigned long next_expiry, flags;
+ unsigned long next_expiry, flags, fl2;
struct mctp_sk_key *key;
struct hlist_node *tmp;
bool next_expiry_valid = false;
@@ -327,15 +475,16 @@ static void mctp_sk_expire_keys(struct timer_list *timer)
spin_lock_irqsave(&net->mctp.keys_lock, flags);
hlist_for_each_entry_safe(key, tmp, &msk->keys, sklist) {
- spin_lock(&key->lock);
+ /* don't expire. manual_alloc is immutable, no locking
+ * required.
+ */
+ if (key->manual_alloc)
+ continue;
+ spin_lock_irqsave(&key->lock, fl2);
if (!time_after_eq(key->expiry, jiffies)) {
- trace_mctp_key_release(key, MCTP_TRACE_KEY_TIMEOUT);
- key->valid = false;
- hlist_del_rcu(&key->hlist);
- hlist_del_rcu(&key->sklist);
- spin_unlock(&key->lock);
- mctp_key_unref(key);
+ __mctp_key_remove(key, net, fl2,
+ MCTP_TRACE_KEY_TIMEOUT);
continue;
}
@@ -346,7 +495,7 @@ static void mctp_sk_expire_keys(struct timer_list *timer)
next_expiry = key->expiry;
next_expiry_valid = true;
}
- spin_unlock(&key->lock);
+ spin_unlock_irqrestore(&key->lock, fl2);
}
spin_unlock_irqrestore(&net->mctp.keys_lock, flags);
@@ -387,9 +536,9 @@ static void mctp_sk_unhash(struct sock *sk)
{
struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
struct net *net = sock_net(sk);
+ unsigned long flags, fl2;
struct mctp_sk_key *key;
struct hlist_node *tmp;
- unsigned long flags;
/* remove from any type-based binds */
mutex_lock(&net->mctp.bind_lock);
@@ -399,20 +548,8 @@ static void mctp_sk_unhash(struct sock *sk)
/* remove tag allocations */
spin_lock_irqsave(&net->mctp.keys_lock, flags);
hlist_for_each_entry_safe(key, tmp, &msk->keys, sklist) {
- hlist_del(&key->sklist);
- hlist_del(&key->hlist);
-
- trace_mctp_key_release(key, MCTP_TRACE_KEY_CLOSED);
-
- spin_lock(&key->lock);
- kfree_skb(key->reasm_head);
- key->reasm_head = NULL;
- key->reasm_dead = true;
- key->valid = false;
- spin_unlock(&key->lock);
-
- /* key is no longer on the lookup lists, unref */
- mctp_key_unref(key);
+ spin_lock_irqsave(&key->lock, fl2);
+ __mctp_key_remove(key, net, fl2, MCTP_TRACE_KEY_CLOSED);
}
spin_unlock_irqrestore(&net->mctp.keys_lock, flags);
}