From 90b271fbd2b9708a8fa79b7e98d90c7919e7ed73 Mon Sep 17 00:00:00 2001
From: Emil Velikov <emil.l.velikov@gmail.com>
Date: Mon, 12 Feb 2024 17:23:05 +0000
Subject: libkmod: clear file->memory if map fails

On mmap failure file->memory is set to -1, which we'll happily pass down
to munmap later on.

More importantly, since we do a NULL check in kmod_file_load_contents()
we will exit the function without (re)attempting the load again.

Since we ignore the return code for the load function(s), one can end up
calling kmod_elf_get_memory() and feed that -1 into init_module.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>
---
 libkmod/libkmod-file.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c
index b6a8cc9..1e1dd35 100644
--- a/libkmod/libkmod-file.c
+++ b/libkmod/libkmod-file.c
@@ -401,8 +401,10 @@ static int load_reg(struct kmod_file *file)
 	file->size = st.st_size;
 	file->memory = mmap(NULL, file->size, PROT_READ, MAP_PRIVATE,
 			    file->fd, 0);
-	if (file->memory == MAP_FAILED)
+	if (file->memory == MAP_FAILED) {
+		file->memory = NULL;
 		return -errno;
+	}
 	file->direct = true;
 	return 0;
 }
-- 
2.27.0