lsm: Refactor return value of LSM hook vm_enough_memory

To be consistent with most LSM hooks, convert the return value of
hook vm_enough_memory to 0 or a negative error code.

Before:
- Hook vm_enough_memory returns 1 if permission is granted, 0 if not.
- LSM_RET_DEFAULT(vm_enough_memory_mm) is 1.

After:
- Hook vm_enough_memory reutrns 0 if permission is granted, negative
  error code if not.
- LSM_RET_DEFAULT(vm_enough_memory_mm) is 0.

Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This commit is contained in:
Xu Kuohai 2024-07-24 10:06:58 +08:00 committed by Paul Moore
parent 61a1dcdceb
commit be72a57527
5 changed files with 14 additions and 27 deletions

View File

@ -48,7 +48,7 @@ LSM_HOOK(int, 0, quota_on, struct dentry *dentry)
LSM_HOOK(int, 0, syslog, int type)
LSM_HOOK(int, 0, settime, const struct timespec64 *ts,
const struct timezone *tz)
LSM_HOOK(int, 1, vm_enough_memory, struct mm_struct *mm, long pages)
LSM_HOOK(int, 0, vm_enough_memory, struct mm_struct *mm, long pages)
LSM_HOOK(int, 0, bprm_creds_for_exec, struct linux_binprm *bprm)
LSM_HOOK(int, 0, bprm_creds_from_file, struct linux_binprm *bprm, const struct file *file)
LSM_HOOK(int, 0, bprm_check_security, struct linux_binprm *bprm)

View File

@ -634,7 +634,7 @@ static inline int security_settime64(const struct timespec64 *ts,
static inline int security_vm_enough_memory_mm(struct mm_struct *mm, long pages)
{
return __vm_enough_memory(mm, pages, cap_vm_enough_memory(mm, pages));
return __vm_enough_memory(mm, pages, !cap_vm_enough_memory(mm, pages));
}
static inline int security_bprm_creds_for_exec(struct linux_binprm *bprm)

View File

@ -1396,17 +1396,12 @@ int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
* Determine whether the allocation of a new virtual mapping by the current
* task is permitted.
*
* Return: 1 if permission is granted, 0 if not.
* Return: 0 if permission granted, negative error code if not.
*/
int cap_vm_enough_memory(struct mm_struct *mm, long pages)
{
int cap_sys_admin = 0;
if (cap_capable(current_cred(), &init_user_ns,
CAP_SYS_ADMIN, CAP_OPT_NOAUDIT) == 0)
cap_sys_admin = 1;
return cap_sys_admin;
return cap_capable(current_cred(), &init_user_ns, CAP_SYS_ADMIN,
CAP_OPT_NOAUDIT);
}
/**

View File

@ -1129,15 +1129,14 @@ int security_vm_enough_memory_mm(struct mm_struct *mm, long pages)
int rc;
/*
* The module will respond with a positive value if
* it thinks the __vm_enough_memory() call should be
* made with the cap_sys_admin set. If all of the modules
* agree that it should be set it will. If any module
* thinks it should not be set it won't.
* The module will respond with 0 if it thinks the __vm_enough_memory()
* call should be made with the cap_sys_admin set. If all of the modules
* agree that it should be set it will. If any module thinks it should
* not be set it won't.
*/
hlist_for_each_entry(hp, &security_hook_heads.vm_enough_memory, list) {
rc = hp->hook.vm_enough_memory(mm, pages);
if (rc <= 0) {
if (rc < 0) {
cap_sys_admin = 0;
break;
}

View File

@ -2202,23 +2202,16 @@ static int selinux_syslog(int type)
}
/*
* Check that a process has enough memory to allocate a new virtual
* mapping. 0 means there is enough memory for the allocation to
* succeed and -ENOMEM implies there is not.
* Check permission for allocating a new virtual mapping. Returns
* 0 if permission is granted, negative error code if not.
*
* Do not audit the selinux permission check, as this is applied to all
* processes that allocate mappings.
*/
static int selinux_vm_enough_memory(struct mm_struct *mm, long pages)
{
int rc, cap_sys_admin = 0;
rc = cred_has_capability(current_cred(), CAP_SYS_ADMIN,
return cred_has_capability(current_cred(), CAP_SYS_ADMIN,
CAP_OPT_NOAUDIT, true);
if (rc == 0)
cap_sys_admin = 1;
return cap_sys_admin;
}
/* binprm security operations */