kernel_samsung_a53x/drivers/uh/kdp.c

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2024-06-15 21:02:09 +02:00
#include <asm-generic/sections.h>
#include <linux/mm.h>
#include "../../mm/slab.h"
#include <linux/slub_def.h>
#include <linux/binfmts.h>
#include <linux/kdp.h>
#include <linux/mount.h>
#include <linux/cred.h>
#include <linux/security.h>
#include <linux/init_task.h>
#include "../../fs/mount.h"
#define VERITY_PARAM_LENGTH 20
#define KDP_CRED_SYS_ID 1000
/* security/selinux/include/objsec.h */
struct task_security_struct {
u32 osid; /* SID prior to last execve */
u32 sid; /* current SID */
u32 exec_sid; /* exec SID */
u32 create_sid; /* fscreate SID */
u32 keycreate_sid; /* keycreate SID */
u32 sockcreate_sid; /* fscreate SID */
void *bp_cred;
};
/* security/selinux/hooks.c */
struct task_security_struct init_sec __kdp_ro;
bool kdp_enable __kdp_ro = false;
static int __check_verifiedboot __kdp_ro = 0;
static char verifiedbootstate[VERITY_PARAM_LENGTH];
void __init kdp_init(void)
{
struct kdp_init cred;
memset((void *)&cred, 0, sizeof(kdp_init));
cred._srodata = (u64)__start_rodata;
cred._erodata = (u64)__end_rodata;
cred.init_mm_pgd = (u64)swapper_pg_dir;
cred.credSize = sizeof(struct cred_kdp);
cred.sp_size = sizeof(struct task_security_struct);
cred.pgd_mm = offsetof(struct mm_struct, pgd);
cred.uid_cred = offsetof(struct cred, uid);
cred.euid_cred = offsetof(struct cred, euid);
cred.gid_cred = offsetof(struct cred, gid);
cred.egid_cred = offsetof(struct cred, egid);
cred.bp_pgd_cred = offsetof(struct cred_kdp, bp_pgd);
cred.bp_task_cred = offsetof(struct cred_kdp, bp_task);
cred.type_cred = offsetof(struct cred_kdp, type);
cred.security_cred = offsetof(struct cred, security);
cred.usage_cred = offsetof(struct cred_kdp, use_cnt);
cred.cred_task = offsetof(struct task_struct, cred);
cred.mm_task = offsetof(struct task_struct, mm);
cred.pid_task = offsetof(struct task_struct, pid);
cred.rp_task = offsetof(struct task_struct, real_parent);
cred.comm_task = offsetof(struct task_struct, comm);
cred.bp_cred_secptr = offsetof(struct task_security_struct, bp_cred);
//cred.verifiedbootstate = (u64)verifiedbootstate;
uh_call(UH_APP_KDP, KDP_INIT, (u64)&cred, 0, 0, 0);
}
static int __init verifiedboot_state_setup(char *str)
{
strlcpy(verifiedbootstate, str, sizeof(verifiedbootstate));
if (!strncmp(verifiedbootstate, "orange", sizeof("orange")))
__check_verifiedboot = 1;
return 0;
}
__setup("androidboot.verifiedbootstate=", verifiedboot_state_setup);
#ifdef CONFIG_KDP_CRED
/*------------------------------------------------
* CRED
*------------------------------------------------
*/
struct cred_kdp_init init_cred_use_cnt = {
.use_cnt = ATOMIC_INIT(4),
.ro_rcu_head_init = {
.non_rcu = 0,
.bp_cred = NULL,
},
};
struct cred_kdp init_cred_kdp __kdp_ro = {
.use_cnt = (atomic_t *)&init_cred_use_cnt,
.bp_task = &init_task,
.bp_pgd = NULL,
.type = 0,
};
static struct kmem_cache *cred_jar_ro;
static struct kmem_cache *tsec_jar;
static struct kmem_cache *usecnt_jar;
/* Dummy constructor to make sure we have separate slabs caches. */
static void cred_ctor(void *data) {}
static void sec_ctor(void *data) {}
static void usecnt_ctor(void *data) {}
void __init kdp_cred_init(void)
{
slab_flags_t flags = SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT;
if (!kdp_enable) {
return;
}
cred_jar_ro = kmem_cache_create("cred_jar_ro",
sizeof(struct cred_kdp),
0, flags, cred_ctor);
if (!cred_jar_ro)
panic("Unable to create RO Cred cache\n");
tsec_jar = kmem_cache_create("tsec_jar",
sizeof(struct task_security_struct),
0, flags, sec_ctor);
if (!tsec_jar)
panic("Unable to create RO security cache\n");
usecnt_jar = kmem_cache_create("usecnt_jar",
sizeof(struct cred_kdp_init),
0, flags, usecnt_ctor);
if (!usecnt_jar)
panic("Unable to create use count jar\n");
uh_call(UH_APP_KDP, JARRO_TSEC_SIZE, (u64)cred_jar_ro->size,
(u64)tsec_jar->size, 0, 0);
}
unsigned int kdp_get_usecount(struct cred *cred)
{
int ret = is_kdp_protect_addr((unsigned long)cred);
if (ret == PROTECT_INIT)
return (unsigned int)atomic_read(init_cred_kdp.use_cnt);
else if (ret == PROTECT_KMEM)
return (unsigned int)atomic_read(((struct cred_kdp *)cred)->use_cnt);
else
return atomic_read(&cred->usage);
}
void kdp_usecount_inc(struct cred *cred)
{
int ret = is_kdp_protect_addr((unsigned long)cred);
if (ret == PROTECT_INIT)
atomic_inc(init_cred_kdp.use_cnt);
else if (ret == PROTECT_KMEM)
atomic_inc(((struct cred_kdp *)cred)->use_cnt);
else
atomic_inc(&cred->usage);
}
unsigned int kdp_usecount_inc_not_zero(struct cred *cred)
{
int ret = is_kdp_protect_addr((unsigned long)cred);
if (ret == PROTECT_INIT)
return (unsigned int)atomic_inc_not_zero(init_cred_kdp.use_cnt);
else if (ret == PROTECT_KMEM)
return (unsigned int)atomic_inc_not_zero(((struct cred_kdp *)cred)->use_cnt);
else
return atomic_inc_not_zero(&cred->usage);
}
unsigned int kdp_usecount_dec_and_test(struct cred *cred)
{
int ret = is_kdp_protect_addr((unsigned long)cred);
if (ret == PROTECT_INIT)
return (unsigned int)atomic_dec_and_test(init_cred_kdp.use_cnt);
else if (ret == PROTECT_KMEM)
return (unsigned int)atomic_dec_and_test(((struct cred_kdp *)cred)->use_cnt);
else
return atomic_dec_and_test(&cred->usage);
}
void kdp_set_cred_non_rcu(struct cred *cred, int val)
{
if (is_kdp_protect_addr((unsigned long)cred))
GET_ROCRED_RCU(cred)->non_rcu = val;
else
cred->non_rcu = val;
}
/* match for kernel/cred.c function */
inline void set_kdp_cred_subscribers(struct cred *cred, int n)
{
#ifdef CONFIG_DEBUG_CREDENTIALS
atomic_set(&cred->subscribers, n);
#endif
}
/* Check whether the address belong to Cred Area */
int is_kdp_protect_addr(unsigned long addr)
{
struct kmem_cache *s;
struct page *page;
void *objp = (void *)addr;
if (!objp)
return 0;
if (!kdp_enable)
return 0;
if ((addr == ((unsigned long)&init_cred)) ||
(addr == ((unsigned long)&init_sec)))
return PROTECT_INIT;
page = virt_to_head_page(objp);
s = page->slab_cache;
if (s && (s == cred_jar_ro || s == tsec_jar))
return PROTECT_KMEM;
return 0;
}
/* We use another function to free protected creds. */
void put_rocred_rcu(struct rcu_head *rcu)
{
struct cred *cred = container_of(rcu, struct ro_rcu_head, rcu)->bp_cred;
if (atomic_read(((struct cred_kdp *)cred)->use_cnt) != 0)
panic("RO_CRED: put_rocred_rcu() sees %p with usage %d\n",
cred, atomic_read(((struct cred_kdp *)cred)->use_cnt));
security_cred_free(cred);
key_put(cred->session_keyring);
key_put(cred->process_keyring);
key_put(cred->thread_keyring);
key_put(cred->request_key_auth);
if (cred->group_info)
put_group_info(cred->group_info);
free_uid(cred->user);
put_user_ns(cred->user_ns);
if (((struct cred_kdp *)cred)->use_cnt)
kmem_cache_free(usecnt_jar, (void *)((struct cred_kdp *)cred)->use_cnt);
kmem_cache_free(cred_jar_ro, cred);
}
void kdp_put_cred_rcu(struct cred *cred, void *put_cred_rcu)
{
if (is_kdp_protect_addr((unsigned long)cred)) {
if (GET_ROCRED_RCU(cred)->non_rcu)
put_rocred_rcu(&(GET_ROCRED_RCU(cred)->rcu));
else
call_rcu(&(GET_ROCRED_RCU(cred)->rcu), put_rocred_rcu);
} else {
void (*f)(struct rcu_head *) = put_cred_rcu;
if (cred->non_rcu)
f(&cred->rcu);
else
call_rcu(&cred->rcu, f);
}
}
/* prepare_ro_creds - Prepare a new set of credentials which is protected by KDP */
struct cred *prepare_ro_creds(struct cred *old, int kdp_cmd, u64 p)
{
u64 pgd = (u64)(current->mm ? current->mm->pgd : swapper_pg_dir);
struct cred_kdp *temp_old;
struct cred_kdp *new_ro = NULL;
struct cred_param param_data;
void *use_cnt_ptr = NULL;
void *rcu_ptr = NULL;
void *tsec = NULL;
new_ro = kmem_cache_alloc(cred_jar_ro, GFP_KERNEL);
if (!new_ro)
panic("[%d] : kmem_cache_alloc() failed", kdp_cmd);
use_cnt_ptr = kmem_cache_alloc(usecnt_jar, GFP_KERNEL);
if (!use_cnt_ptr)
panic("[%d] : Unable to allocate usage pointer\n", kdp_cmd);
temp_old = kmalloc(sizeof(struct cred_kdp), GFP_KERNEL);
if (!temp_old)
panic("[%d] : Unable to allocate temp_old\n", kdp_cmd);
// get_usecnt_rcu
rcu_ptr = &((struct cred_kdp_init *)use_cnt_ptr)->ro_rcu_head_init;
((struct ro_rcu_head *)rcu_ptr)->bp_cred = (void *)new_ro;
tsec = kmem_cache_alloc(tsec_jar, GFP_KERNEL);
if (!tsec)
panic("[%d] : Unable to allocate security pointer\n", kdp_cmd);
// make cred_kdp 'temp_old'
if ((u64)current->cred == (u64)&init_cred)
memcpy(temp_old, &init_cred_kdp, sizeof(struct cred_kdp));
else
memcpy(temp_old, current->cred, sizeof(struct cred_kdp));
memcpy(temp_old, old, sizeof(struct cred));
// init
memset((void *)&param_data, 0, sizeof(struct cred_param));
param_data.cred = temp_old;
param_data.cred_ro = new_ro;
param_data.use_cnt_ptr = use_cnt_ptr;
param_data.sec_ptr = tsec;
param_data.type = kdp_cmd;
param_data.use_cnt = (u64)p;
uh_call(UH_APP_KDP, PREPARE_RO_CRED, (u64)&param_data, (u64)current, (u64)&init_cred, (u64)&init_cred_kdp);
kfree(temp_old);
if (kdp_cmd == CMD_COPY_CREDS) {
if ((new_ro->bp_task != (void *)p) ||
new_ro->cred.security != tsec ||
new_ro->use_cnt != use_cnt_ptr) {
panic("[%d]: KDP Call failed task=0x%lx:0x%lx, sec=0x%lx:0x%lx, usecnt=0x%lx:0x%lx",
kdp_cmd, new_ro->bp_task, (void *)p,
new_ro->cred.security, tsec, new_ro->use_cnt, use_cnt_ptr);
}
} else {
if ((new_ro->bp_task != current) ||
(current->mm && new_ro->bp_pgd != (void *)pgd) ||
(new_ro->cred.security != tsec) ||
(new_ro->use_cnt != use_cnt_ptr)) {
panic("[%d]: KDP Call failed task=0x%lx:0x%lx, sec=0x%lx:0x%lx, usecnt=0x%lx:0x%lx, pgd=0x%lx:0x%lx",
kdp_cmd, new_ro->bp_task, current, new_ro->cred.security, tsec,
new_ro->use_cnt, use_cnt_ptr, new_ro->bp_pgd, (void *)pgd);
}
}
GET_ROCRED_RCU(new_ro)->non_rcu = old->non_rcu;
GET_ROCRED_RCU(new_ro)->reflected_cred = 0;
atomic_set(new_ro->use_cnt, 2);
set_kdp_cred_subscribers((struct cred *)new_ro, 0);
get_group_info(new_ro->cred.group_info);
get_uid(new_ro->cred.user);
get_user_ns(new_ro->cred.user_ns);
#ifdef CONFIG_KEYS
key_get(new_ro->cred.session_keyring);
key_get(new_ro->cred.process_keyring);
key_get(new_ro->cred.thread_keyring);
key_get(new_ro->cred.request_key_auth);
#endif
validate_creds((struct cred *)new_ro);
return (struct cred *)new_ro;
}
/* security/selinux/hooks.c */
static bool is_kdp_tsec_jar(unsigned long addr)
{
struct kmem_cache *s;
struct page *page;
void *objp = (void *)addr;
if (!objp)
return false;
page = virt_to_head_page(objp);
s = page->slab_cache;
if (s && s == tsec_jar)
return true;
return false;
}
static inline int chk_invalid_kern_ptr(u64 tsec)
{
return (((u64)tsec >> 39) != (u64)0x1FFFFFF);
}
void kdp_free_security(unsigned long tsec)
{
if (!tsec || chk_invalid_kern_ptr(tsec))
return;
if (is_kdp_tsec_jar(tsec))
kmem_cache_free(tsec_jar, (void *)tsec);
else
kfree((void *)tsec);
}
void kdp_assign_pgd(struct task_struct *p)
{
u64 pgd = (u64)(p->mm ? p->mm->pgd : swapper_pg_dir);
uh_call(UH_APP_KDP, SET_CRED_PGD, (u64)p->cred, (u64)pgd, 0, 0);
}
struct task_security_struct init_sec __kdp_ro;
static inline unsigned int cmp_sec_integrity(const struct cred *cred, struct mm_struct *mm)
{
if (cred == &init_cred) {
if (init_cred_kdp.bp_task != current)
printk(KERN_ERR "[KDP] init_cred_kdp.bp_task: 0x%lx, current: 0x%lx\n",
init_cred_kdp.bp_task, current);
if (mm && (init_cred_kdp.bp_pgd != swapper_pg_dir) && (init_cred_kdp.bp_pgd != mm->pgd ))
printk(KERN_ERR "[KDP] mm: 0x%lx, init_cred_kdp.bp_pgd: 0x%lx, swapper_pg_dir: %p, mm->pgd: 0x%lx\n",
mm, init_cred_kdp.bp_pgd, swapper_pg_dir, mm->pgd);
return ((init_cred_kdp.bp_task != current) ||
(mm && (!(in_interrupt() || in_softirq())) &&
(init_cred_kdp.bp_pgd != swapper_pg_dir) &&
(init_cred_kdp.bp_pgd != mm->pgd)));
} else {
if (((struct cred_kdp *)cred)->bp_task != current)
printk(KERN_ERR "[KDP] cred->bp_task: 0x%lx, current: 0x%lx\n",
((struct cred_kdp *)cred)->bp_task, current);
if (mm && (((struct cred_kdp *)cred)->bp_pgd != swapper_pg_dir) &&
(((struct cred_kdp *)cred)->bp_pgd != mm->pgd))
printk(KERN_ERR "[KDP] mm: 0x%lx, cred->bp_pgd: 0x%lx, swapper_pg_dir: %p, mm->pgd: 0x%lx\n",
mm, ((struct cred_kdp *)cred)->bp_pgd, swapper_pg_dir, mm->pgd);
return ((((struct cred_kdp *)cred)->bp_task != current) ||
(mm && (!(in_interrupt() || in_softirq())) &&
(((struct cred_kdp *)cred)->bp_pgd != swapper_pg_dir) &&
(((struct cred_kdp *)cred)->bp_pgd != mm->pgd)));
}
// Want to not reaching
return 1;
}
static inline bool is_kdp_invalid_cred_sp(u64 cred, u64 sec_ptr)
{
struct task_security_struct *tsec = (struct task_security_struct *)sec_ptr;
u64 cred_size = sizeof(struct cred_kdp);
u64 tsec_size = sizeof(struct task_security_struct);
if (cred == (u64)&init_cred)
cred_size = sizeof(struct cred);
if ((cred == (u64)&init_cred) && (sec_ptr == (u64)&init_sec))
return false;
if (!is_kdp_protect_addr(cred) ||
!is_kdp_protect_addr(cred + cred_size) ||
!is_kdp_protect_addr(sec_ptr) ||
!is_kdp_protect_addr(sec_ptr + tsec_size)) {
printk(KERN_ERR, "[KDP] cred: %d, cred + sizeof(cred): %d, sp: %d, sp + sizeof(tsec): %d",
is_kdp_protect_addr(cred),
is_kdp_protect_addr(cred + cred_size),
is_kdp_protect_addr(sec_ptr),
is_kdp_protect_addr(sec_ptr + tsec_size));
return true;
}
if ((u64)tsec->bp_cred != cred) {
printk(KERN_ERR, "[KDP] %s: tesc->bp_cred: %lx, cred: %lx\n",
__func__, (u64)tsec->bp_cred, cred);
return true;
}
return false;
}
inline int kdp_restrict_fork(struct filename *path)
{
struct cred *shellcred;
const struct cred_kdp *cred_kdp = (const struct cred_kdp *)(current->cred);
if (!strcmp(path->name, "/system/bin/patchoat") ||
!strcmp(path->name, "/system/bin/idmap2")) {
return 0;
}
if ((cred_kdp->type) >> 1 & 1) {
shellcred = prepare_creds();
if (!shellcred)
return 1;
shellcred->uid.val = 2000;
shellcred->gid.val = 2000;
shellcred->euid.val = 2000;
shellcred->egid.val = 2000;
commit_creds(shellcred);
}
return 0;
}
#endif
/* This function is related to Namespace */
#ifdef CONFIG_KDP_NS
static unsigned int cmp_ns_integrity(void)
{
struct kdp_mount *root = NULL;
struct nsproxy *nsp = NULL;
if (in_interrupt() || in_softirq())
return 0;
nsp = current->nsproxy;
if (!nsp || !nsp->mnt_ns)
return 0;
root = (struct kdp_mount *)current->nsproxy->mnt_ns->root;
if (root != (struct kdp_mount *)((struct kdp_vfsmount *)root->mnt)->bp_mount) {
printk(KERN_ERR "[KDP] NameSpace Mismatch %lx != %lx\n nsp: 0x%lx, mnt_ns: 0x%lx\n",
root, ((struct kdp_vfsmount *)root->mnt)->bp_mount, nsp, nsp->mnt_ns);
return 1;
}
return 0;
}
/*------------------------------------------------
* Namespace
*------------------------------------------------
*/
static DEFINE_SPINLOCK(mnt_vfsmnt_lock);
static struct kmem_cache *vfsmnt_cache __read_mostly;
extern int __is_kdp_recovery;
void cred_ctor_vfsmount(void *data)
{
/* Dummy constructor to make sure we have separate slabs caches. */
}
void __init kdp_mnt_init(void)
{
struct ns_param nsparam;
vfsmnt_cache = kmem_cache_create("vfsmnt_cache", sizeof(struct kdp_vfsmount),
0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, cred_ctor_vfsmount);
if (!vfsmnt_cache)
panic("Failed to allocate vfsmnt_cache\n");
memset((void *)&nsparam, 0, sizeof(struct ns_param));
nsparam.ns_buff_size = (u64)vfsmnt_cache->size;
nsparam.ns_size = (u64)sizeof(struct kdp_vfsmount);
nsparam.bp_offset = (u64)offsetof(struct kdp_vfsmount, bp_mount);
nsparam.sb_offset = (u64)offsetof(struct kdp_vfsmount, mnt.mnt_sb);
nsparam.flag_offset = (u64)offsetof(struct kdp_vfsmount, mnt.mnt_flags);
uh_call(UH_APP_KDP, NS_INIT, (u64)&nsparam, 0, 0, 0);
}
bool is_kdp_vfsmnt_cache(unsigned long addr)
{
static void *objp;
static struct kmem_cache *s;
static struct page *page;
objp = (void *)addr;
if (!objp)
return false;
page = virt_to_head_page(objp);
s = page->slab_cache;
if (s && s == vfsmnt_cache)
return true;
return false;
}
inline void kdp_set_mnt_root_sb(struct vfsmount *mnt, struct dentry *mnt_root, struct super_block *mnt_sb)
{
uh_call(UH_APP_KDP, SET_NS_ROOT_SB, (u64)mnt, (u64)mnt_root, (u64)mnt_sb, 0);
}
inline void kdp_assign_mnt_flags(struct vfsmount *mnt, int flags)
{
uh_call(UH_APP_KDP, SET_NS_FLAGS, (u64)mnt, (u64)flags, 0, 0);
}
inline void kdp_clear_mnt_flags(struct vfsmount *mnt, int flags)
{
int f = mnt->mnt_flags;
f &= ~flags;
kdp_assign_mnt_flags(mnt, f);
}
void kdp_set_mnt_flags(struct vfsmount *mnt, int flags)
{
int f = mnt->mnt_flags;
f |= flags;
kdp_assign_mnt_flags(mnt, f);
}
int kdp_mnt_alloc_vfsmount(struct mount *mnt)
{
struct kdp_vfsmount *vfsmnt = NULL;
vfsmnt = kmem_cache_alloc(vfsmnt_cache, GFP_KERNEL);
if (!vfsmnt)
return 1;
spin_lock(&mnt_vfsmnt_lock);
uh_call(UH_APP_KDP, SET_NS_BP, (u64)vfsmnt, (u64)mnt, 0, 0);
((struct kdp_mount *)mnt)->mnt = (struct vfsmount *)vfsmnt;
spin_unlock(&mnt_vfsmnt_lock);
return 0;
}
void kdp_free_vfsmount(void *objp)
{
kmem_cache_free(vfsmnt_cache, objp);
}
#endif
#ifdef CONFIG_KDP_CRED
/* Main function to verify cred security context of a process */
int security_integrity_current(void)
{
const struct cred *cur_cred = current_cred();
rcu_read_lock();
if (kdp_enable &&
(is_kdp_invalid_cred_sp((u64)cur_cred, (u64)cur_cred->security)
|| cmp_sec_integrity(cur_cred, current->mm)
#ifdef CONFIG_KDP_NS
|| cmp_ns_integrity()
#endif
)) {
rcu_read_unlock();
panic("KDP CRED PROTECTION VIOLATION\n");
}
rcu_read_unlock();
return 0;
}
#endif
inline int get_kdp_kmem_cache_type(const char *name)
{
if (name) {
#ifdef CONFIG_KDP_CRED
if (!strncmp(name, CRED_JAR_RO, strlen(CRED_JAR_RO)))
return CRED_JAR_TYPE;
if (!strncmp(name, TSEC_JAR, strlen(TSEC_JAR)))
return TSEC_JAR_TYPE;
#endif
#ifdef CONFIG_KDP_NS
if (!strncmp(name, VFSMNT_JAR, strlen(VFSMNT_JAR)))
return VFSMNT_JAR_TYPE;
#endif
}
return UNKNOWN_JAR_TYPE;
}
inline bool is_kdp_kmem_cache_name(const char *name)
{
if (name) {
#ifdef CONFIG_KDP_CRED
if (!strncmp(name, CRED_JAR_RO, strlen(CRED_JAR_RO)) ||
!strncmp(name, TSEC_JAR, strlen(TSEC_JAR)))
return true;
#endif
#ifdef CONFIG_KDP_NS
if (!strncmp(name, VFSMNT_JAR, strlen(VFSMNT_JAR)))
return true;
#endif
}
return false;
}
inline bool is_kdp_kmem_cache(struct kmem_cache *s)
{
if (!s->name)
return false;
#ifdef CONFIG_KDP_CRED
if (s == cred_jar_ro || s == tsec_jar)
return true;
#endif
#ifdef CONFIG_KDP_NS
if (s == vfsmnt_cache)
return true;
#endif
return false;
}