idevicebackup: Fix crash if manifest is sent early on in the backup process

1 files changed, 3 insertions, 2 deletions

diff --git a/tools/idevicebackup.c b/tools/idevicebackup.c
index 7935477..dbba217 100644
--- a/tools/idevicebackup.c
+++ b/tools/idevicebackup.c
@@ -455,9 +455,10 @@ static int plist_strcmp(plist_t node, const char *str)
 
 static char *mobilebackup_build_path(const char *backup_directory, const char *name, const char *extension)
 {
-        char* filename = (char*)malloc(strlen(name)+strlen(extension)+1);
+        char* filename = (char*)malloc(strlen(name)+(extension == NULL ? 0: strlen(extension))+1);
         strcpy(filename, name);
-        strcat(filename, extension);
+        if (extension != NULL)
+                strcat(filename, extension);
         char *path = build_path(backup_directory, filename, NULL);
         free(filename);
         return path;