convert a bunch of open-coded instances of memdup_user_nul()

A _lot_ of ->write() instances were open-coding it; some are
converted to memdup_user_nul(), a lot more remain...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

12 files changed, 71 insertions, 197 deletions

diff --git a/arch/xtensa/platforms/iss/simdisk.c b/arch/xtensa/platforms/iss/simdisk.c
index 3c3ace2c46b6..f58a4e6472cb 100644
--- a/arch/xtensa/platforms/iss/simdisk.c
+++ b/arch/xtensa/platforms/iss/simdisk.c
@@ -227,16 +227,12 @@ static ssize_t proc_read_simdisk(struct file *file, char __user *buf,
 static ssize_t proc_write_simdisk(struct file *file, const char __user *buf,
 			size_t count, loff_t *ppos)
 {
-	char *tmp = kmalloc(count + 1, GFP_KERNEL);
+	char *tmp = memdup_user_nul(buf, count);
 	struct simdisk *dev = PDE_DATA(file_inode(file));
 	int err;
 
-	if (tmp == NULL)
-		return -ENOMEM;
-	if (copy_from_user(tmp, buf, count)) {
-		err = -EFAULT;
-		goto out_free;
-	}
+	if (IS_ERR(tmp))
+		return PTR_ERR(tmp);
 
 	err = simdisk_detach(dev);
 	if (err != 0)
@@ -244,8 +240,6 @@ static ssize_t proc_write_simdisk(struct file *file, const char __user *buf,
 
 	if (count > 0 && tmp[count - 1] == '\n')
 		tmp[count - 1] = 0;
-	else
-		tmp[count] = 0;
 
 	if (tmp[0])
 		err = simdisk_attach(dev, tmp);
diff --git a/drivers/net/wireless/ath/wil6210/debugfs.c b/drivers/net/wireless/ath/wil6210/debugfs.c
index 97bc186f9728..a1d10b85989f 100644
--- a/drivers/net/wireless/ath/wil6210/debugfs.c
+++ b/drivers/net/wireless/ath/wil6210/debugfs.c
@@ -580,16 +580,10 @@ static ssize_t wil_write_file_rxon(struct file *file, const char __user *buf,
 	long channel;
 	bool on;
 
-	char *kbuf = kmalloc(len + 1, GFP_KERNEL);
-
-	if (!kbuf)
-		return -ENOMEM;
-	if (copy_from_user(kbuf, buf, len)) {
-		kfree(kbuf);
-		return -EIO;
-	}
+	char *kbuf = memdup_user_nul(buf, len);
 
-	kbuf[len] = '\0';
+	if (IS_ERR(kbuf))
+		return PTR_ERR(kbuf);
 	rc = kstrtol(kbuf, 0, &channel);
 	kfree(kbuf);
 	if (rc)
diff --git a/drivers/s390/char/vmcp.c b/drivers/s390/char/vmcp.c
index 0fdedadff7bc..2a67b496a9e2 100644
--- a/drivers/s390/char/vmcp.c
+++ b/drivers/s390/char/vmcp.c
@@ -88,14 +88,9 @@ vmcp_write(struct file *file, const char __user *buff, size_t count,
 
 	if (count > 240)
 		return -EINVAL;
-	cmd = kmalloc(count + 1, GFP_KERNEL);
-	if (!cmd)
-		return -ENOMEM;
-	if (copy_from_user(cmd, buff, count)) {
-		kfree(cmd);
-		return -EFAULT;
-	}
-	cmd[count] = '\0';
+	cmd = memdup_user_nul(buff, count);
+	if (IS_ERR(cmd))
+		return PTR_ERR(cmd);
 	session = file->private_data;
 	if (mutex_lock_interruptible(&session->mutex)) {
 		kfree(cmd);
diff --git a/drivers/sbus/char/openprom.c b/drivers/sbus/char/openprom.c
index 5843288f64bc..e077ebd89319 100644
--- a/drivers/sbus/char/openprom.c
+++ b/drivers/sbus/char/openprom.c
@@ -390,16 +390,9 @@ static int copyin_string(char __user *user, size_t len, char **ptr)
 	if ((ssize_t)len < 0 || (ssize_t)(len + 1) < 0)
 		return -EINVAL;
 
-	tmp = kmalloc(len + 1, GFP_KERNEL);
-	if (!tmp)
-		return -ENOMEM;
-
-	if (copy_from_user(tmp, user, len)) {
-		kfree(tmp);
-		return -EFAULT;
-	}
-
-	tmp[len] = '\0';
+	tmp = memdup_user_nul(user, len);
+	if (IS_ERR(tmp))
+		return PTR_ERR(tmp);
 
 	*ptr = tmp;
 
diff --git a/fs/afs/proc.c b/fs/afs/proc.c
index 24a905b076fd..2853b4095344 100644
--- a/fs/afs/proc.c
+++ b/fs/afs/proc.c
@@ -230,14 +230,9 @@ static ssize_t afs_proc_cells_write(struct file *file, const char __user *buf,
 	if (size <= 1 || size >= PAGE_SIZE)
 		return -EINVAL;
 
-	kbuf = kmalloc(size + 1, GFP_KERNEL);
-	if (!kbuf)
-		return -ENOMEM;
-
-	ret = -EFAULT;
-	if (copy_from_user(kbuf, buf, size) != 0)
-		goto done;
-	kbuf[size] = 0;
+	kbuf = memdup_user_nul(buf, size);
+	if (IS_ERR(kbuf))
+		return PTR_ERR(kbuf);
 
 	/* trim to first NL */
 	name = memchr(kbuf, '\n', size);
@@ -315,15 +310,9 @@ static ssize_t afs_proc_rootcell_write(struct file *file,
 	if (size <= 1 || size >= PAGE_SIZE)
 		return -EINVAL;
 
-	ret = -ENOMEM;
-	kbuf = kmalloc(size + 1, GFP_KERNEL);
-	if (!kbuf)
-		goto nomem;
-
-	ret = -EFAULT;
-	if (copy_from_user(kbuf, buf, size) != 0)
-		goto infault;
-	kbuf[size] = 0;
+	kbuf = memdup_user_nul(buf, size);
+	if (IS_ERR(kbuf))
+		return PTR_ERR(kbuf);
 
 	/* trim to first NL */
 	s = memchr(kbuf, '\n', size);
@@ -337,9 +326,7 @@ static ssize_t afs_proc_rootcell_write(struct file *file,
 	if (ret >= 0)
 		ret = size;	/* consume everything, always */
 
-infault:
 	kfree(kbuf);
-nomem:
 	_leave(" = %d", ret);
 	return ret;
 }
diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c
index f601def05bdf..452e98dd7560 100644
--- a/fs/cachefiles/daemon.c
+++ b/fs/cachefiles/daemon.c
@@ -226,15 +226,9 @@ static ssize_t cachefiles_daemon_write(struct file *file,
 		return -EOPNOTSUPP;
 
 	/* drag the command string into the kernel so we can parse it */
-	data = kmalloc(datalen + 1, GFP_KERNEL);
-	if (!data)
-		return -ENOMEM;
-
-	ret = -EFAULT;
-	if (copy_from_user(data, _data, datalen) != 0)
-		goto error;
-
-	data[datalen] = '\0';
+	data = memdup_user_nul(_data, datalen);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
 
 	ret = -EINVAL;
 	if (memchr(data, '\0', datalen))
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index 173b3873a4f4..1925d6d222b8 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -515,14 +515,9 @@ static ssize_t device_write(struct file *file, const char __user *buf,
 	if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
 		return -EINVAL;
 
-	kbuf = kzalloc(count + 1, GFP_NOFS);
-	if (!kbuf)
-		return -ENOMEM;
-
-	if (copy_from_user(kbuf, buf, count)) {
-		error = -EFAULT;
-		goto out_free;
-	}
+	kbuf = memdup_user_nul(buf, count);
+	if (!IS_ERR(kbuf))
+		return PTR_ERR(kbuf);
 
 	if (check_version(kbuf)) {
 		error = -EBADE;
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index a990824c8604..2aeb6ffc0a1e 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -349,16 +349,10 @@ static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
 	if (count >= BLK_TN_MAX_MSG)
 		return -EINVAL;
 
-	msg = kmalloc(count + 1, GFP_KERNEL);
-	if (msg == NULL)
-		return -ENOMEM;
-
-	if (copy_from_user(msg, buffer, count)) {
-		kfree(msg);
-		return -EFAULT;
-	}
+	msg = memdup_user_nul(buffer, count);
+	if (IS_ERR(msg))
+		return PTR_ERR(msg);
 
-	msg[count] = '\0';
 	bt = filp->private_data;
 	__trace_note_message(bt, "%s", msg);
 	kfree(msg);
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index e3952e9c8ec0..fe42b6ec3f0c 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -657,14 +657,9 @@ static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
 		pr_warn("expected <%d bytes into control\n", USER_BUF_PAGE);
 		return -E2BIG;
 	}
-	tmpbuf = kmalloc(len + 1, GFP_KERNEL);
-	if (!tmpbuf)
-		return -ENOMEM;
-	if (copy_from_user(tmpbuf, ubuf, len)) {
-		kfree(tmpbuf);
-		return -EFAULT;
-	}
-	tmpbuf[len] = '\0';
+	tmpbuf = memdup_user_nul(ubuf, len);
+	if (IS_ERR(tmpbuf))
+		return PTR_ERR(tmpbuf);
 	vpr_info("read %d bytes from userspace\n", (int)len);
 
 	ret = ddebug_exec_queries(tmpbuf, NULL);
diff --git a/net/rxrpc/ar-key.c b/net/rxrpc/ar-key.c
index da3cc09f683e..3f6571651d32 100644
--- a/net/rxrpc/ar-key.c
+++ b/net/rxrpc/ar-key.c
@@ -896,15 +896,9 @@ int rxrpc_request_key(struct rxrpc_sock *rx, char __user *optval, int optlen)
 	if (optlen <= 0 || optlen > PAGE_SIZE - 1)
 		return -EINVAL;
 
-	description = kmalloc(optlen + 1, GFP_KERNEL);
-	if (!description)
-		return -ENOMEM;
-
-	if (copy_from_user(description, optval, optlen)) {
-		kfree(description);
-		return -EFAULT;
-	}
-	description[optlen] = 0;
+	description = memdup_user_nul(optval, optlen);
+	if (IS_ERR(description))
+		return PTR_ERR(description);
 
 	key = request_key(&key_type_rxrpc, description, NULL);
 	if (IS_ERR(key)) {
@@ -933,15 +927,9 @@ int rxrpc_server_keyring(struct rxrpc_sock *rx, char __user *optval,
 	if (optlen <= 0 || optlen > PAGE_SIZE - 1)
 		return -EINVAL;
 
-	description = kmalloc(optlen + 1, GFP_KERNEL);
-	if (!description)
-		return -ENOMEM;
-
-	if (copy_from_user(description, optval, optlen)) {
-		kfree(description);
-		return -EFAULT;
-	}
-	description[optlen] = 0;
+	description = memdup_user_nul(optval, optlen);
+	if (IS_ERR(description))
+		return PTR_ERR(description);
 
 	key = request_key(&key_type_keyring, description, NULL);
 	if (IS_ERR(key)) {
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 94bd9e41c9ec..e249a66db533 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -497,14 +497,9 @@ static ssize_t smk_write_rules_list(struct file *file, const char __user *buf,
 		}
 	}
 
-	data = kmalloc(count + 1, GFP_KERNEL);
-	if (data == NULL)
-		return -ENOMEM;
-
-	if (copy_from_user(data, buf, count) != 0) {
-		rc = -EFAULT;
-		goto out;
-	}
+	data = memdup_user_nul(buf, count);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
 
 	/*
 	 * In case of parsing only part of user buf,
@@ -884,16 +879,10 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
 	    (count < SMK_CIPSOMIN || count > SMK_CIPSOMAX))
 		return -EINVAL;
 
-	data = kzalloc(count + 1, GFP_KERNEL);
-	if (data == NULL)
-		return -ENOMEM;
-
-	if (copy_from_user(data, buf, count) != 0) {
-		rc = -EFAULT;
-		goto unlockedout;
-	}
+	data = memdup_user_nul(buf, count);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
 
-	data[count] = '\0';
 	rule = data;
 	/*
 	 * Only allow one writer at a time. Writes should be
@@ -946,7 +935,6 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
 
 out:
 	mutex_unlock(&smack_cipso_lock);
-unlockedout:
 	kfree(data);
 	return rc;
 }
@@ -1187,14 +1175,9 @@ static ssize_t smk_write_net4addr(struct file *file, const char __user *buf,
 	if (count < SMK_NETLBLADDRMIN)
 		return -EINVAL;
 
-	data = kzalloc(count + 1, GFP_KERNEL);
-	if (data == NULL)
-		return -ENOMEM;
-
-	if (copy_from_user(data, buf, count) != 0) {
-		rc = -EFAULT;
-		goto free_data_out;
-	}
+	data = memdup_user_nul(buf, count);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
 
 	smack = kzalloc(count + 1, GFP_KERNEL);
 	if (smack == NULL) {
@@ -1202,8 +1185,6 @@ static ssize_t smk_write_net4addr(struct file *file, const char __user *buf,
 		goto free_data_out;
 	}
 
-	data[count] = '\0';
-
 	rc = sscanf(data, "%hhd.%hhd.%hhd.%hhd/%u %s",
 		&host[0], &host[1], &host[2], &host[3], &masks, smack);
 	if (rc != 6) {
@@ -1454,14 +1435,9 @@ static ssize_t smk_write_net6addr(struct file *file, const char __user *buf,
 	if (count < SMK_NETLBLADDRMIN)
 		return -EINVAL;
 
-	data = kzalloc(count + 1, GFP_KERNEL);
-	if (data == NULL)
-		return -ENOMEM;
-
-	if (copy_from_user(data, buf, count) != 0) {
-		rc = -EFAULT;
-		goto free_data_out;
-	}
+	data = memdup_user_nul(buf, count);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
 
 	smack = kzalloc(count + 1, GFP_KERNEL);
 	if (smack == NULL) {
@@ -1469,8 +1445,6 @@ static ssize_t smk_write_net6addr(struct file *file, const char __user *buf,
 		goto free_data_out;
 	}
 
-	data[count] = '\0';
-
 	i = sscanf(data, "%x:%x:%x:%x:%x:%x:%x:%x/%u %s",
 			&scanned[0], &scanned[1], &scanned[2], &scanned[3],
 			&scanned[4], &scanned[5], &scanned[6], &scanned[7],
@@ -1865,14 +1839,9 @@ static ssize_t smk_write_ambient(struct file *file, const char __user *buf,
 	if (!smack_privileged(CAP_MAC_ADMIN))
 		return -EPERM;
 
-	data = kzalloc(count + 1, GFP_KERNEL);
-	if (data == NULL)
-		return -ENOMEM;
-
-	if (copy_from_user(data, buf, count) != 0) {
-		rc = -EFAULT;
-		goto out;
-	}
+	data = memdup_user_nul(buf, count);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
 
 	skp = smk_import_entry(data, count);
 	if (IS_ERR(skp)) {
@@ -2041,14 +2010,9 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
 	if (!smack_privileged(CAP_MAC_ADMIN))
 		return -EPERM;
 
-	data = kzalloc(count + 1, GFP_KERNEL);
-	if (data == NULL)
-		return -ENOMEM;
-
-	if (copy_from_user(data, buf, count) != 0) {
-		kfree(data);
-		return -EFAULT;
-	}
+	data = memdup_user_nul(buf, count);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
 
 	rc = smk_parse_label_list(data, &list_tmp);
 	kfree(data);
@@ -2133,14 +2097,9 @@ static ssize_t smk_write_unconfined(struct file *file, const char __user *buf,
 	if (!smack_privileged(CAP_MAC_ADMIN))
 		return -EPERM;
 
-	data = kzalloc(count + 1, GFP_KERNEL);
-	if (data == NULL)
-		return -ENOMEM;
-
-	if (copy_from_user(data, buf, count) != 0) {
-		rc = -EFAULT;
-		goto freeout;
-	}
+	data = memdup_user_nul(buf, count);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
 
 	/*
 	 * Clear the smack_unconfined on invalid label errors. This means
@@ -2696,19 +2655,15 @@ static ssize_t smk_write_syslog(struct file *file, const char __user *buf,
 	if (!smack_privileged(CAP_MAC_ADMIN))
 		return -EPERM;
 
-	data = kzalloc(count + 1, GFP_KERNEL);
-	if (data == NULL)
-		return -ENOMEM;
+	data = memdup_user_nul(buf, count);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
 
-	if (copy_from_user(data, buf, count) != 0)
-		rc = -EFAULT;
-	else {
-		skp = smk_import_entry(data, count);
-		if (IS_ERR(skp))
-			rc = PTR_ERR(skp);
-		else
-			smack_syslog_label = skp;
-	}
+	skp = smk_import_entry(data, count);
+	if (IS_ERR(skp))
+		rc = PTR_ERR(skp);
+	else
+		smack_syslog_label = skp;
 
 	kfree(data);
 	return rc;
@@ -2798,14 +2753,9 @@ static ssize_t smk_write_relabel_self(struct file *file, const char __user *buf,
 	if (*ppos != 0)
 		return -EINVAL;
 
-	data = kzalloc(count + 1, GFP_KERNEL);
-	if (data == NULL)
-		return -ENOMEM;
-
-	if (copy_from_user(data, buf, count) != 0) {
-		kfree(data);
-		return -EFAULT;
-	}
+	data = memdup_user_nul(buf, count);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
 
 	rc = smk_parse_label_list(data, &list_tmp);
 	kfree(data);
diff --git a/security/tomoyo/securityfs_if.c b/security/tomoyo/securityfs_if.c
index 179a955b319d..06ab41b1ff28 100644
--- a/security/tomoyo/securityfs_if.c
+++ b/security/tomoyo/securityfs_if.c
@@ -43,13 +43,9 @@ static ssize_t tomoyo_write_self(struct file *file, const char __user *buf,
 	int error;
 	if (!count || count >= TOMOYO_EXEC_TMPSIZE - 10)
 		return -ENOMEM;
-	data = kzalloc(count + 1, GFP_NOFS);
-	if (!data)
-		return -ENOMEM;
-	if (copy_from_user(data, buf, count)) {
-		error = -EFAULT;
-		goto out;
-	}
+	data = memdup_user_nul(buf, count);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
 	tomoyo_normalize_line(data);
 	if (tomoyo_correct_domain(data)) {
 		const int idx = tomoyo_read_lock();
@@ -87,7 +83,6 @@ static ssize_t tomoyo_write_self(struct file *file, const char __user *buf,
 		tomoyo_read_unlock(idx);
 	} else
 		error = -EINVAL;
-out:
 	kfree(data);
 	return error ? error : count;
 }