Merge tag '9p-for-6.15-rc1' of https://github.com/martinetd/linux

Pull 9p updates from Dominique Martinet:

 - fix handling of bogus (negative/too long) replies

 - fix crash on mkdir with ACLs (... looks like nobody is using ACLs
   with semi-recent kernels...)

 - ipv6 support for trans=tcp

 - minor concurrency fix to make syzbot happy

 - minor cleanup

* tag '9p-for-6.15-rc1' of https://github.com/martinetd/linux:
  docs: fs/9p: Add missing "not" in cache documentation
  9p: Use hashtable.h for hash_errmap
  Documentation/fs/9p: fix broken link
  9p/trans_fd: mark concurrent read and writes to p9_conn->err
  9p/net: return error on bogus (longer than requested) replies
  9p/net: fix improper handling of bogus negative read/write replies
  fs/9p: fix NULL pointer dereference on mkdir
  net/9p/fd: support ipv6 for trans=tcp

3 files changed, 69 insertions, 69 deletions

diff --git a/net/9p/client.c b/net/9p/client.c
index 09f8ced9f8bb..61461b9fa134 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -1548,7 +1548,8 @@ p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
 	struct p9_client *clnt = fid->clnt;
 	struct p9_req_t *req;
 	int count = iov_iter_count(to);
-	int rsize, received, non_zc = 0;
+	u32 rsize, received;
+	bool non_zc = false;
 	char *dataptr;
 
 	*err = 0;
@@ -1571,7 +1572,7 @@ p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
 				       0, 11, "dqd", fid->fid,
 				       offset, rsize);
 	} else {
-		non_zc = 1;
+		non_zc = true;
 		req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
 				    rsize);
 	}
@@ -1592,11 +1593,13 @@ p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
 		return 0;
 	}
 	if (rsize < received) {
-		pr_err("bogus RREAD count (%d > %d)\n", received, rsize);
-		received = rsize;
+		pr_err("bogus RREAD count (%u > %u)\n", received, rsize);
+		*err = -EIO;
+		p9_req_put(clnt, req);
+		return 0;
 	}
 
-	p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", received);
+	p9_debug(P9_DEBUG_9P, "<<< RREAD count %u\n", received);
 
 	if (non_zc) {
 		int n = copy_to_iter(dataptr, received, to);
@@ -1623,9 +1626,9 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
 	*err = 0;
 
 	while (iov_iter_count(from)) {
-		int count = iov_iter_count(from);
-		int rsize = fid->iounit;
-		int written;
+		size_t count = iov_iter_count(from);
+		u32 rsize = fid->iounit;
+		u32 written;
 
 		if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
 			rsize = clnt->msize - P9_IOHDRSZ;
@@ -1633,7 +1636,7 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
 		if (count < rsize)
 			rsize = count;
 
-		p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %d (/%d)\n",
+		p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %u (/%zu)\n",
 			 fid->fid, offset, rsize, count);
 
 		/* Don't bother zerocopy for small IO (< 1024) */
@@ -1659,11 +1662,14 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
 			break;
 		}
 		if (rsize < written) {
-			pr_err("bogus RWRITE count (%d > %d)\n", written, rsize);
-			written = rsize;
+			pr_err("bogus RWRITE count (%u > %u)\n", written, rsize);
+			*err = -EIO;
+			iov_iter_revert(from, count - iov_iter_count(from));
+			p9_req_put(clnt, req);
+			break;
 		}
 
-		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", written);
+		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %u\n", written);
 
 		p9_req_put(clnt, req);
 		iov_iter_revert(from, count - written - iov_iter_count(from));
@@ -1712,7 +1718,7 @@ p9_client_write_subreq(struct netfs_io_subrequest *subreq)
 
 	if (written > len) {
 		pr_err("bogus RWRITE count (%d > %u)\n", written, len);
-		written = len;
+		written = -EIO;
 	}
 
 	p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", len);
@@ -2098,7 +2104,8 @@ EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
 
 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
 {
-	int err, rsize, non_zc = 0;
+	int err, non_zc = 0;
+	u32 rsize;
 	struct p9_client *clnt;
 	struct p9_req_t *req;
 	char *dataptr;
@@ -2107,7 +2114,7 @@ int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
 
 	iov_iter_kvec(&to, ITER_DEST, &kv, 1, count);
 
-	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
+	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %u\n",
 		 fid->fid, offset, count);
 
 	clnt = fid->clnt;
@@ -2142,11 +2149,12 @@ int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
 		goto free_and_error;
 	}
 	if (rsize < count) {
-		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
-		count = rsize;
+		pr_err("bogus RREADDIR count (%u > %u)\n", count, rsize);
+		err = -EIO;
+		goto free_and_error;
 	}
 
-	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
+	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %u\n", count);
 
 	if (non_zc)
 		memmove(data, dataptr, count);
diff --git a/net/9p/error.c b/net/9p/error.c
index 8da744494b68..8ba8afc91482 100644
--- a/net/9p/error.c
+++ b/net/9p/error.c
@@ -16,6 +16,7 @@
 #include <linux/list.h>
 #include <linux/jhash.h>
 #include <linux/errno.h>
+#include <linux/hashtable.h>
 #include <net/9p/9p.h>
 
 /**
@@ -33,8 +34,8 @@ struct errormap {
 	struct hlist_node list;
 };
 
-#define ERRHASHSZ		32
-static struct hlist_head hash_errmap[ERRHASHSZ];
+#define ERRHASH_BITS 5
+static DEFINE_HASHTABLE(hash_errmap, ERRHASH_BITS);
 
 /* FixMe - reduce to a reasonable size */
 static struct errormap errmap[] = {
@@ -176,18 +177,14 @@ static struct errormap errmap[] = {
 int p9_error_init(void)
 {
 	struct errormap *c;
-	int bucket;
-
-	/* initialize hash table */
-	for (bucket = 0; bucket < ERRHASHSZ; bucket++)
-		INIT_HLIST_HEAD(&hash_errmap[bucket]);
+	u32 hash;
 
 	/* load initial error map into hash table */
 	for (c = errmap; c->name; c++) {
 		c->namelen = strlen(c->name);
-		bucket = jhash(c->name, c->namelen, 0) % ERRHASHSZ;
+		hash = jhash(c->name, c->namelen, 0);
 		INIT_HLIST_NODE(&c->list);
-		hlist_add_head(&c->list, &hash_errmap[bucket]);
+		hash_add(hash_errmap, &c->list, hash);
 	}
 
 	return 1;
@@ -205,12 +202,12 @@ int p9_errstr2errno(char *errstr, int len)
 {
 	int errno;
 	struct errormap *c;
-	int bucket;
+	u32 hash;
 
 	errno = 0;
 	c = NULL;
-	bucket = jhash(errstr, len, 0) % ERRHASHSZ;
-	hlist_for_each_entry(c, &hash_errmap[bucket], list) {
+	hash = jhash(errstr, len, 0);
+	hash_for_each_possible(hash_errmap, c, list, hash) {
 		if (c->namelen == len && !memcmp(c->name, errstr, len)) {
 			errno = c->val;
 			break;
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index 196060dc6138..339ec4e54778 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -11,6 +11,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/in.h>
+#include <linux/in6.h>
 #include <linux/module.h>
 #include <linux/net.h>
 #include <linux/ipv6.h>
@@ -191,12 +192,13 @@ static void p9_conn_cancel(struct p9_conn *m, int err)
 
 	spin_lock(&m->req_lock);
 
-	if (m->err) {
+	if (READ_ONCE(m->err)) {
 		spin_unlock(&m->req_lock);
 		return;
 	}
 
-	m->err = err;
+	WRITE_ONCE(m->err, err);
+	ASSERT_EXCLUSIVE_WRITER(m->err);
 
 	list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) {
 		list_move(&req->req_list, &cancel_list);
@@ -283,7 +285,7 @@ static void p9_read_work(struct work_struct *work)
 
 	m = container_of(work, struct p9_conn, rq);
 
-	if (m->err < 0)
+	if (READ_ONCE(m->err) < 0)
 		return;
 
 	p9_debug(P9_DEBUG_TRANS, "start mux %p pos %zd\n", m, m->rc.offset);
@@ -450,7 +452,7 @@ static void p9_write_work(struct work_struct *work)
 
 	m = container_of(work, struct p9_conn, wq);
 
-	if (m->err < 0) {
+	if (READ_ONCE(m->err) < 0) {
 		clear_bit(Wworksched, &m->wsched);
 		return;
 	}
@@ -622,7 +624,7 @@ static void p9_poll_mux(struct p9_conn *m)
 	__poll_t n;
 	int err = -ECONNRESET;
 
-	if (m->err < 0)
+	if (READ_ONCE(m->err) < 0)
 		return;
 
 	n = p9_fd_poll(m->client, NULL, &err);
@@ -665,6 +667,7 @@ static void p9_poll_mux(struct p9_conn *m)
 static int p9_fd_request(struct p9_client *client, struct p9_req_t *req)
 {
 	__poll_t n;
+	int err;
 	struct p9_trans_fd *ts = client->trans;
 	struct p9_conn *m = &ts->conn;
 
@@ -673,9 +676,10 @@ static int p9_fd_request(struct p9_client *client, struct p9_req_t *req)
 
 	spin_lock(&m->req_lock);
 
-	if (m->err < 0) {
+	err = READ_ONCE(m->err);
+	if (err < 0) {
 		spin_unlock(&m->req_lock);
-		return m->err;
+		return err;
 	}
 
 	WRITE_ONCE(req->status, REQ_STATUS_UNSENT);
@@ -954,64 +958,55 @@ static void p9_fd_close(struct p9_client *client)
 	kfree(ts);
 }
 
-/*
- * stolen from NFS - maybe should be made a generic function?
- */
-static inline int valid_ipaddr4(const char *buf)
-{
-	int rc, count, in[4];
-
-	rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]);
-	if (rc != 4)
-		return -EINVAL;
-	for (count = 0; count < 4; count++) {
-		if (in[count] > 255)
-			return -EINVAL;
-	}
-	return 0;
-}
-
 static int p9_bind_privport(struct socket *sock)
 {
-	struct sockaddr_in cl;
+	struct sockaddr_storage stor = { 0 };
 	int port, err = -EINVAL;
 
-	memset(&cl, 0, sizeof(cl));
-	cl.sin_family = AF_INET;
-	cl.sin_addr.s_addr = htonl(INADDR_ANY);
+	stor.ss_family = sock->ops->family;
+	if (stor.ss_family == AF_INET)
+		((struct sockaddr_in *)&stor)->sin_addr.s_addr = htonl(INADDR_ANY);
+	else
+		((struct sockaddr_in6 *)&stor)->sin6_addr = in6addr_any;
 	for (port = p9_ipport_resv_max; port >= p9_ipport_resv_min; port--) {
-		cl.sin_port = htons((ushort)port);
-		err = kernel_bind(sock, (struct sockaddr *)&cl, sizeof(cl));
+		if (stor.ss_family == AF_INET)
+			((struct sockaddr_in *)&stor)->sin_port = htons((ushort)port);
+		else
+			((struct sockaddr_in6 *)&stor)->sin6_port = htons((ushort)port);
+		err = kernel_bind(sock, (struct sockaddr *)&stor, sizeof(stor));
 		if (err != -EADDRINUSE)
 			break;
 	}
 	return err;
 }
 
-
 static int
 p9_fd_create_tcp(struct p9_client *client, const char *addr, char *args)
 {
 	int err;
+	char port_str[6];
 	struct socket *csocket;
-	struct sockaddr_in sin_server;
+	struct sockaddr_storage stor = { 0 };
 	struct p9_fd_opts opts;
 
 	err = parse_opts(args, &opts);
 	if (err < 0)
 		return err;
 
-	if (addr == NULL || valid_ipaddr4(addr) < 0)
+	if (!addr)
 		return -EINVAL;
 
+	sprintf(port_str, "%u", opts.port);
+	err = inet_pton_with_scope(current->nsproxy->net_ns, AF_UNSPEC, addr,
+				   port_str, &stor);
+	if (err < 0)
+		return err;
+
 	csocket = NULL;
 
 	client->trans_opts.tcp.port = opts.port;
 	client->trans_opts.tcp.privport = opts.privport;
-	sin_server.sin_family = AF_INET;
-	sin_server.sin_addr.s_addr = in_aton(addr);
-	sin_server.sin_port = htons(opts.port);
-	err = __sock_create(current->nsproxy->net_ns, PF_INET,
+	err = __sock_create(current->nsproxy->net_ns, stor.ss_family,
 			    SOCK_STREAM, IPPROTO_TCP, &csocket, 1);
 	if (err) {
 		pr_err("%s (%d): problem creating socket\n",
@@ -1030,8 +1025,8 @@ p9_fd_create_tcp(struct p9_client *client, const char *addr, char *args)
 	}
 
 	err = READ_ONCE(csocket->ops)->connect(csocket,
-				    (struct sockaddr *)&sin_server,
-				    sizeof(struct sockaddr_in), 0);
+					       (struct sockaddr *)&stor,
+					       sizeof(stor), 0);
 	if (err < 0) {
 		pr_err("%s (%d): problem connecting socket to %s\n",
 		       __func__, task_pid_nr(current), addr);