1 files changed, 12 insertions, 11 deletions

diff --git a/security/keys/trusted.c b/security/keys/trusted.c
index bd85315cbfeb..98aa89ff7bfd 100644
--- a/security/keys/trusted.c
+++ b/security/keys/trusted.c
@@ -1147,20 +1147,21 @@ static long trusted_read(const struct key *key, char __user *buffer,
         p = dereference_key_locked(key);
         if (!p)
                 return -EINVAL;
-        if (!buffer || buflen <= 0)
-                return 2 * p->blob_len;
-        ascii_buf = kmalloc(2 * p->blob_len, GFP_KERNEL);
-        if (!ascii_buf)
-                return -ENOMEM;
 
-        bufp = ascii_buf;
-        for (i = 0; i < p->blob_len; i++)
-                bufp = hex_byte_pack(bufp, p->blob[i]);
-        if ((copy_to_user(buffer, ascii_buf, 2 * p->blob_len)) != 0) {
+        if (buffer && buflen >= 2 * p->blob_len) {
+                ascii_buf = kmalloc(2 * p->blob_len, GFP_KERNEL);
+                if (!ascii_buf)
+                        return -ENOMEM;
+
+                bufp = ascii_buf;
+                for (i = 0; i < p->blob_len; i++)
+                        bufp = hex_byte_pack(bufp, p->blob[i]);
+                if (copy_to_user(buffer, ascii_buf, 2 * p->blob_len) != 0) {
+                        kzfree(ascii_buf);
+                        return -EFAULT;
+                }
                 kzfree(ascii_buf);
-                return -EFAULT;
         }
-        kzfree(ascii_buf);
         return 2 * p->blob_len;
 }