leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

sched: move no_new_privs into new atomic flags

Browse Source 
Since seccomp transitions between threads requires updates to the
no_new_privs flag to be atomic, the flag must be part of an atomic flag
set. This moves the nnp flag into a separate task field, and introduces
accessors.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
This commit is contained in:
Kees Cook 2014-05-21 15:23:46 -07:00
parent 8855d608c1
commit 1d4457f999
5 changed files with 22 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
fs/exec.c
View File

@ -1234,7 +1234,7 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
* This isn't strictly necessary, but it makes it harder for LSMs to
* mess up.
*/
if (current->no_new_privs)
if (task_no_new_privs(current))
bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS;
t = p;
@ -1272,7 +1272,7 @@ int prepare_binprm(struct linux_binprm *bprm)
bprm->cred->egid = current_egid();
if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) &&
!current->no_new_privs &&
!task_no_new_privs(current) &&
kuid_has_mapping(bprm->cred->user_ns, inode->i_uid) &&
kgid_has_mapping(bprm->cred->user_ns, inode->i_gid)) {
/* Set-uid? */

18
include/linux/sched.h
View File

@ -1307,13 +1307,12 @@ struct task_struct {
* execve */
unsigned in_iowait:1;
/* task may not gain privileges */
unsigned no_new_privs:1;
/* Revert to default priority/policy when forking */
unsigned sched_reset_on_fork:1;
unsigned sched_contributes_to_load:1;
unsigned long atomic_flags; /* Flags needing atomic access. */
pid_t pid;
pid_t tgid;
@ -1967,6 +1966,19 @@ static inline void memalloc_noio_restore(unsigned int flags)
current->flags = (current->flags & ~PF_MEMALLOC_NOIO) | flags;
}
/* Per-process atomic flags. */
#define PFA_NO_NEW_PRIVS 0x00000001 /* May not gain new privileges. */
static inline bool task_no_new_privs(struct task_struct *p)
{
return test_bit(PFA_NO_NEW_PRIVS, &p->atomic_flags);
}
static inline void task_set_no_new_privs(struct task_struct *p)
{
set_bit(PFA_NO_NEW_PRIVS, &p->atomic_flags);
}
/*
* task->jobctl flags
*/

2
kernel/seccomp.c
View File

@ -241,7 +241,7 @@ static long seccomp_attach_filter(struct sock_fprog *fprog)
* This avoids scenarios where unprivileged tasks can affect the
* behavior of privileged children.
*/
if (!current->no_new_privs &&
if (!task_no_new_privs(current) &&
security_capable_noaudit(current_cred(), current_user_ns(),
CAP_SYS_ADMIN) != 0)
return -EACCES;

4
kernel/sys.c
View File

@ -1990,12 +1990,12 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
if (arg2 != 1 || arg3 || arg4 || arg5)
return -EINVAL;
current->no_new_privs = 1;
task_set_no_new_privs(current);
break;
case PR_GET_NO_NEW_PRIVS:
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;
return current->no_new_privs ? 1 : 0;
return task_no_new_privs(current) ? 1 : 0;
case PR_GET_THP_DISABLE:
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;

4
security/apparmor/domain.c
View File

@ -621,7 +621,7 @@ int aa_change_hat(const char *hats[], int count, u64 token, bool permtest)
* There is no exception for unconfined as change_hat is not
* available.
*/
if (current->no_new_privs)
if (task_no_new_privs(current))
return -EPERM;
/* released below */
@ -776,7 +776,7 @@ int aa_change_profile(const char *ns_name, const char *hname, bool onexec,
* no_new_privs is set because this aways results in a reduction
* of permissions.
*/
if (current->no_new_privs && !unconfined(profile)) {
if (task_no_new_privs(current) && !unconfined(profile)) {
put_cred(cred);
return -EPERM;
}