diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c
index 96063e355186..13fe8e3b48f3 100644
--- a/fs/smb/client/smb2inode.c
+++ b/fs/smb/client/smb2inode.c
@@ -77,6 +77,17 @@ static int parse_posix_sids(struct cifs_open_info_data *data,
 
 	sidsbuf = (u8 *)qi + le16_to_cpu(qi->OutputBufferOffset) + qi_len;
 	sidsbuf_end = sidsbuf + out_len - qi_len;
+	if (sidsbuf_end < sidsbuf) {
+		cifs_dbg(VFS, "%s: server-supplied out_len %u caused pointer wraparound\n",
+			 __func__, out_len);
+		return -EINVAL;
+	}
+	if (sidsbuf_end > (u8 *)rsp_iov->iov_base + rsp_iov->iov_len) {
+		cifs_dbg(VFS, "%s: server-supplied out_len %u overruns iov by %td bytes\n",
+			 __func__, out_len,
+			 sidsbuf_end - ((u8 *)rsp_iov->iov_base + rsp_iov->iov_len));
+		return -EINVAL;
+	}
 
 	owner_len = posix_info_sid_size(sidsbuf, sidsbuf_end);
 	if (owner_len == -1)