Unverified Commit a6323bd4 authored by Petr Pavlu's avatar Petr Pavlu Committed by Daniel Gomez
Browse files

module: Prevent silent truncation of module name in delete_module(2) 



Passing a module name longer than MODULE_NAME_LEN to the delete_module
syscall results in its silent truncation. This really isn't much of
a problem in practice, but it could theoretically lead to the removal of an
incorrect module. It is more sensible to return ENAMETOOLONG or ENOENT in
such a case.

Update the syscall to return ENOENT, as documented in the delete_module(2)
man page to mean "No module by that name exists." This is appropriate
because a module with a name longer than MODULE_NAME_LEN cannot be loaded
in the first place.

Signed-off-by: default avatarPetr Pavlu <petr.pavlu@suse.com>
Reviewed-by: default avatarDaniel Gomez <da.gomez@samsung.com>
Link: https://lore.kernel.org/r/20250630143535.267745-2-petr.pavlu@suse.com


Signed-off-by: default avatarDaniel Gomez <da.gomez@samsung.com>
parent 768da2ea

kernel/module/main.c

+6 −4
Original line number Diff line number Diff line
@@ -779,14 +779,16 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user, 
	struct module *mod;

	char name[MODULE_NAME_LEN];

	char buf[MODULE_FLAGS_BUF_SIZE];

	int ret, forced = 0;

	int ret, len, forced = 0;



	if (!capable(CAP_SYS_MODULE) || modules_disabled)

		return -EPERM;



	if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0)

		return -EFAULT;

	name[MODULE_NAME_LEN-1] = '\0';

	len = strncpy_from_user(name, name_user, MODULE_NAME_LEN);

	if (len == 0 || len == MODULE_NAME_LEN)

		return -ENOENT;

	if (len < 0)

		return len;



	audit_log_kern_module(name);