diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 4aecdc8f74b2..04a53cdb409f 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -1186,7 +1186,7 @@ static ssize_t smk_write_net4addr(struct file *file, const char __user *buf,
 		return -EPERM;
 	if (*ppos != 0)
 		return -EINVAL;
-	if (count < SMK_NETLBLADDRMIN)
+	if (count < SMK_NETLBLADDRMIN || count > PAGE_SIZE - 1)
 		return -EINVAL;
 
 	data = memdup_user_nul(buf, count);
@@ -1446,7 +1446,7 @@ static ssize_t smk_write_net6addr(struct file *file, const char __user *buf,
 		return -EPERM;
 	if (*ppos != 0)
 		return -EINVAL;
-	if (count < SMK_NETLBLADDRMIN)
+	if (count < SMK_NETLBLADDRMIN || count > PAGE_SIZE - 1)
 		return -EINVAL;
 
 	data = memdup_user_nul(buf, count);
@@ -1853,6 +1853,10 @@ static ssize_t smk_write_ambient(struct file *file, const char __user *buf,
 	if (!smack_privileged(CAP_MAC_ADMIN))
 		return -EPERM;
 
+	/* Enough data must be present */
+	if (count == 0 || count > PAGE_SIZE)
+		return -EINVAL;
+
 	data = memdup_user_nul(buf, count);
 	if (IS_ERR(data))
 		return PTR_ERR(data);
@@ -2024,6 +2028,9 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
 	if (!smack_privileged(CAP_MAC_ADMIN))
 		return -EPERM;
 
+	if (count > PAGE_SIZE)
+		return -EINVAL;
+
 	data = memdup_user_nul(buf, count);
 	if (IS_ERR(data))
 		return PTR_ERR(data);
@@ -2111,6 +2118,9 @@ static ssize_t smk_write_unconfined(struct file *file, const char __user *buf,
 	if (!smack_privileged(CAP_MAC_ADMIN))
 		return -EPERM;
 
+	if (count > PAGE_SIZE)
+		return -EINVAL;
+
 	data = memdup_user_nul(buf, count);
 	if (IS_ERR(data))
 		return PTR_ERR(data);
@@ -2664,6 +2674,10 @@ static ssize_t smk_write_syslog(struct file *file, const char __user *buf,
 	if (!smack_privileged(CAP_MAC_ADMIN))
 		return -EPERM;
 
+	/* Enough data must be present */
+	if (count == 0 || count > PAGE_SIZE)
+		return -EINVAL;
+
 	data = memdup_user_nul(buf, count);
 	if (IS_ERR(data))
 		return PTR_ERR(data);
@@ -2756,10 +2770,13 @@ static ssize_t smk_write_relabel_self(struct file *file, const char __user *buf,
 		return -EPERM;
 
 	/*
+	 * No partial write.
 	 * Enough data must be present.
 	 */
 	if (*ppos != 0)
 		return -EINVAL;
+	if (count == 0 || count > PAGE_SIZE)
+		return -EINVAL;
 
 	data = memdup_user_nul(buf, count);
 	if (IS_ERR(data))