From 64f977a3cedf4aefee82e5a698c06d604a22abce Mon Sep 17 00:00:00 2001
From: Michael Tremer <michael.tremer@ipfire.org>
Date: Tue, 16 Mar 2021 17:59:48 +0000
Subject: [PATCH] compress: xfopen: Check for valid inputs

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---
 src/libpakfire/compress.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/libpakfire/compress.c b/src/libpakfire/compress.c
index f92acea1e..ffe870391 100644
--- a/src/libpakfire/compress.c
+++ b/src/libpakfire/compress.c
@@ -18,6 +18,7 @@
 #                                                                             #
 #############################################################################*/
 
+#include <errno.h>
 #include <stdio.h>
 #include <string.h>
 
@@ -50,8 +51,21 @@ struct xz_cookie {
 FILE* pakfire_xfopen(FILE* f, const char* mode) {
 	char buffer[MAX_MAGIC_LENGTH];
 
-	if (!f)
+	if (!f) {
+		errno = EBADFD;
 		return NULL;
+	}
+
+	if (!mode) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	// This only works for reading files
+	if (*mode != 'r') {
+		errno = ENOTSUP;
+		return NULL;
+	}
 
 	fpos_t pos;
 
-- 
2.47.2