From: Emil Velikov <emil.l.velikov@gmail.com>
Date: Mon, 12 Feb 2024 17:23:05 +0000 (+0000)
Subject: libkmod: clear file->memory if map fails
X-Git-Tag: v33~63
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=90b271fbd2b9708a8fa79b7e98d90c7919e7ed73;p=thirdparty%2Fkmod.git

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>
---

diff --git a/libkmod/libkmod-file.c b/libkmod/libkmod-file.c
index abd4723b..b408aed2 100644
--- a/libkmod/libkmod-file.c
+++ b/libkmod/libkmod-file.c
@@ -392,8 +392,10 @@ 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;
+	}
 
 	return 0;
 }