Re: [PATCH kmod 04/13] libkmod: clear file->memory if map fails

[Lucas De Marchi <lucas.demarchi@intel.com>]

On Mon, Feb 12, 2024 at 05:23:05PM GMT, Emil Velikov via B4 Relay wrote:
>From: Emil Velikov <emil.l.velikov@gmail.com>
>
>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>

Lucas De Marchi

>---
> 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 abd4723..b408aed 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;
> }
>
>-- 
>2.43.0
>