[PATCH 4/4] module: Add hook for security_kernel_post_read_file()

Kees Cook
2020-07-07T08:19:51Z

Calls to security_kernel_load_data() should be paired with a call to
security_kernel_post_read_file() with a NULL file argument. Add the
missing call so the module contents are visible to the LSMs interested
in measuring the module content. (This also paves the way for moving
module signature checking out of the module core and into an LSM.)

Cc: Jessica Yu <jeyu@kernel.org>
Fixes: c77b8cdf745d ("module: replace the existing LSM hook in init_module")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
kernel/module.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/module.c b/kernel/module.c
index 0c6573b98c36..af9679f8e5c6 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2980,7 +2980,12 @@ static int copy_module_from_user(const void __user *umod, unsigned long len,
return -EFAULT;
}

- return 0;
+ err = security_kernel_post_read_file(NULL, (char *)info->hdr,
+ info->len, READING_MODULE);
+ if (err)
+ vfree(info->hdr);
+
+ return err;
}

static void free_copy(struct load_info *info)
--
2.25.1