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-rw-r--r--kernel/sys.c75
1 files changed, 49 insertions, 26 deletions
diff --git a/kernel/sys.c b/kernel/sys.c
index 5761c53..af468ed 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -120,16 +120,33 @@ EXPORT_SYMBOL(cad_pid);
void (*pm_power_off_prepare)(void);
/*
+ * Returns true if current's euid is same as p's uid or euid,
+ * or has CAP_SYS_NICE to p's user_ns.
+ *
+ * Called with rcu_read_lock, creds are safe
+ */
+static bool set_one_prio_perm(struct task_struct *p)
+{
+ const struct cred *cred = current_cred(), *pcred = __task_cred(p);
+
+ if (pcred->user->user_ns == cred->user->user_ns &&
+ (pcred->uid == cred->euid ||
+ pcred->euid == cred->euid))
+ return true;
+ if (ns_capable(pcred->user->user_ns, CAP_SYS_NICE))
+ return true;
+ return false;
+}
+
+/*
* set the priority of a task
* - the caller must hold the RCU read lock
*/
static int set_one_prio(struct task_struct *p, int niceval, int error)
{
- const struct cred *cred = current_cred(), *pcred = __task_cred(p);
int no_nice;
- if (pcred->uid != cred->euid &&
- pcred->euid != cred->euid && !capable(CAP_SYS_NICE)) {
+ if (!set_one_prio_perm(p)) {
error = -EPERM;
goto out;
}
@@ -506,7 +523,7 @@ SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
if (rgid != (gid_t) -1) {
if (old->gid == rgid ||
old->egid == rgid ||
- capable(CAP_SETGID))
+ nsown_capable(CAP_SETGID))
new->gid = rgid;
else
goto error;
@@ -515,7 +532,7 @@ SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
if (old->gid == egid ||
old->egid == egid ||
old->sgid == egid ||
- capable(CAP_SETGID))
+ nsown_capable(CAP_SETGID))
new->egid = egid;
else
goto error;
@@ -550,7 +567,7 @@ SYSCALL_DEFINE1(setgid, gid_t, gid)
old = current_cred();
retval = -EPERM;
- if (capable(CAP_SETGID))
+ if (nsown_capable(CAP_SETGID))
new->gid = new->egid = new->sgid = new->fsgid = gid;
else if (gid == old->gid || gid == old->sgid)
new->egid = new->fsgid = gid;
@@ -617,7 +634,7 @@ SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
new->uid = ruid;
if (old->uid != ruid &&
old->euid != ruid &&
- !capable(CAP_SETUID))
+ !nsown_capable(CAP_SETUID))
goto error;
}
@@ -626,7 +643,7 @@ SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
if (old->uid != euid &&
old->euid != euid &&
old->suid != euid &&
- !capable(CAP_SETUID))
+ !nsown_capable(CAP_SETUID))
goto error;
}
@@ -674,7 +691,7 @@ SYSCALL_DEFINE1(setuid, uid_t, uid)
old = current_cred();
retval = -EPERM;
- if (capable(CAP_SETUID)) {
+ if (nsown_capable(CAP_SETUID)) {
new->suid = new->uid = uid;
if (uid != old->uid) {
retval = set_user(new);
@@ -716,7 +733,7 @@ SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
old = current_cred();
retval = -EPERM;
- if (!capable(CAP_SETUID)) {
+ if (!nsown_capable(CAP_SETUID)) {
if (ruid != (uid_t) -1 && ruid != old->uid &&
ruid != old->euid && ruid != old->suid)
goto error;
@@ -780,7 +797,7 @@ SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
old = current_cred();
retval = -EPERM;
- if (!capable(CAP_SETGID)) {
+ if (!nsown_capable(CAP_SETGID)) {
if (rgid != (gid_t) -1 && rgid != old->gid &&
rgid != old->egid && rgid != old->sgid)
goto error;
@@ -840,7 +857,7 @@ SYSCALL_DEFINE1(setfsuid, uid_t, uid)
if (uid == old->uid || uid == old->euid ||
uid == old->suid || uid == old->fsuid ||
- capable(CAP_SETUID)) {
+ nsown_capable(CAP_SETUID)) {
if (uid != old_fsuid) {
new->fsuid = uid;
if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
@@ -873,7 +890,7 @@ SYSCALL_DEFINE1(setfsgid, gid_t, gid)
if (gid == old->gid || gid == old->egid ||
gid == old->sgid || gid == old->fsgid ||
- capable(CAP_SETGID)) {
+ nsown_capable(CAP_SETGID)) {
if (gid != old_fsgid) {
new->fsgid = gid;
goto change_okay;
@@ -1183,6 +1200,7 @@ SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
+
if (len < 0 || len > __NEW_UTS_LEN)
return -EINVAL;
down_write(&uts_sem);
@@ -1230,7 +1248,7 @@ SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
int errno;
char tmp[__NEW_UTS_LEN];
- if (!capable(CAP_SYS_ADMIN))
+ if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
if (len < 0 || len > __NEW_UTS_LEN)
return -EINVAL;
@@ -1345,6 +1363,8 @@ int do_prlimit(struct task_struct *tsk, unsigned int resource,
rlim = tsk->signal->rlim + resource;
task_lock(tsk->group_leader);
if (new_rlim) {
+ /* Keep the capable check against init_user_ns until
+ cgroups can contain all limits */
if (new_rlim->rlim_max > rlim->rlim_max &&
!capable(CAP_SYS_RESOURCE))
retval = -EPERM;
@@ -1388,19 +1408,22 @@ static int check_prlimit_permission(struct task_struct *task)
{
const struct cred *cred = current_cred(), *tcred;
- tcred = __task_cred(task);
- if (current != task &&
- (cred->uid != tcred->euid ||
- cred->uid != tcred->suid ||
- cred->uid != tcred->uid ||
- cred->gid != tcred->egid ||
- cred->gid != tcred->sgid ||
- cred->gid != tcred->gid) &&
- !capable(CAP_SYS_RESOURCE)) {
- return -EPERM;
- }
+ if (current == task)
+ return 0;
- return 0;
+ tcred = __task_cred(task);
+ if (cred->user->user_ns == tcred->user->user_ns &&
+ (cred->uid == tcred->euid &&
+ cred->uid == tcred->suid &&
+ cred->uid == tcred->uid &&
+ cred->gid == tcred->egid &&
+ cred->gid == tcred->sgid &&
+ cred->gid == tcred->gid))
+ return 0;
+ if (ns_capable(tcred->user->user_ns, CAP_SYS_RESOURCE))
+ return 0;
+
+ return -EPERM;
}
SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
generated by cgit v1.1 at 2024-05-16 04:31:18 +0000