[lineage-19] Fix CVE-2021-3968

drivers/android/binder.c

@@ -552,6 +552,7 @@ struct binder_proc {
 	struct task_struct *tsk;
 	struct files_struct *files;
 	struct mutex files_lock;
+	const struct cred *cred;
 	struct hlist_node deferred_work_node;
 	int deferred_work;
 	bool is_dead;
@@ -2503,7 +2504,7 @@ static int binder_translate_binder(struct flat_binder_object *fp,
 		ret = -EINVAL;
 		goto done;
 	}
-	if (security_binder_transfer_binder(proc->tsk, target_proc->tsk)) {
+	if (security_binder_transfer_binder(proc->cred, target_proc->cred)) {
 		ret = -EPERM;
 		goto done;
 	}
@@ -2549,7 +2550,7 @@ static int binder_translate_handle(struct flat_binder_object *fp,
 				  proc->pid, thread->pid, fp->handle);
 		return -EINVAL;
 	}
-	if (security_binder_transfer_binder(proc->tsk, target_proc->tsk)) {
+	if (security_binder_transfer_binder(proc->cred, target_proc->cred)) {
 		ret = -EPERM;
 		goto done;
 	}
@@ -2633,7 +2634,7 @@ static int binder_translate_fd(int fd,
 		ret = -EBADF;
 		goto err_fget;
 	}
-	ret = security_binder_transfer_file(proc->tsk, target_proc->tsk, file);
+	ret = security_binder_transfer_file(proc->cred, target_proc->cred, file);
 	if (ret < 0) {
 		ret = -EPERM;
 		goto err_security;
@@ -3024,8 +3025,8 @@ static void binder_transaction(struct binder_proc *proc,
 			return_error_line = __LINE__;
 			goto err_invalid_target_handle;
 		}
-		if (security_binder_transaction(proc->tsk,
-						target_proc->tsk) < 0) {
+		if (security_binder_transaction(proc->cred,
+						target_proc->cred) < 0) {
 			return_error = BR_FAILED_REPLY;
 			return_error_param = -EPERM;
 			return_error_line = __LINE__;
@@ -3136,7 +3137,7 @@ static void binder_transaction(struct binder_proc *proc,
 		size_t added_size;
 		int max_retries = 100;
 
-		security_task_getsecid(proc->tsk, &secid);
+		security_cred_getsecid(proc->cred, &secid);
  retry_alloc:
 		ret = security_secid_to_secctx(secid, &secctx, &secctx_sz);
 		if (ret == -ENOMEM && max_retries-- > 0) {
@@ -4574,6 +4575,7 @@ static void binder_free_proc(struct binder_proc *proc)
 	BUG_ON(!list_empty(&proc->delivered_death));
 	binder_alloc_deferred_release(&proc->alloc);
 	put_task_struct(proc->tsk);
+	put_cred(proc->cred);
 	binder_stats_deleted(BINDER_STAT_PROC);
 	kfree(proc);
 }
@@ -4776,7 +4778,7 @@ static int binder_ioctl_set_ctx_mgr(struct file *filp,
 		ret = -EBUSY;
 		goto out;
 	}
-	ret = security_binder_set_context_mgr(proc->tsk);
+	ret = security_binder_set_context_mgr(proc->cred);
 	if (ret < 0)
 		goto out;
 	if (uid_valid(context->binder_context_mgr_uid)) {
@@ -5097,6 +5099,7 @@ static int binder_open(struct inode *nodp, struct file *filp)
 	atomic_set(&proc->tmp_ref, 0);
 	get_task_struct(current->group_leader);
 	proc->tsk = current->group_leader;
+	proc->cred = get_cred(filp->f_cred);
 	mutex_init(&proc->files_lock);
 	INIT_LIST_HEAD(&proc->todo);
 	if (binder_supported_policy(current->policy)) {

include/linux/lsm_hooks.h

@@ -528,6 +528,10 @@
  *	@new points to the new credentials.
  *	@old points to the original credentials.
  *	Transfer data from original creds to new creds
+ * @cred_getsecid:
+ *	Retrieve the security identifier of the cred structure @c
+ *	@c contains the credentials, secid will be placed into @secid.
+ *	In case of failure, @secid will be set to zero.
  * @kernel_act_as:
  *	Set the credentials for a kernel service to act as (subjective context).
  *	@new points to the credentials to be modified.
@@ -1121,22 +1125,22 @@
  *
  * @binder_set_context_mgr
  *	Check whether @mgr is allowed to be the binder context manager.
- *	@mgr contains the task_struct for the task being registered.
+ *	@mgr contains the struct cred for the current binder process.
  *	Return 0 if permission is granted.
  * @binder_transaction
  *	Check whether @from is allowed to invoke a binder transaction call
  *	to @to.
- *	@from contains the task_struct for the sending task.
- *	@to contains the task_struct for the receiving task.
- * @binder_transfer_binder
+ *	@from contains the struct cred for the sending process.
+ *	@to contains the struct cred for the receiving process.
+ * @binder_transfer_binder:
  *	Check whether @from is allowed to transfer a binder reference to @to.
- *	@from contains the task_struct for the sending task.
- *	@to contains the task_struct for the receiving task.
- * @binder_transfer_file
+ *	@from contains the struct cred for the sending process.
+ *	@to contains the struct cred for the receiving process.
+ * @binder_transfer_file:
  *	Check whether @from is allowed to transfer @file to @to.
- *	@from contains the task_struct for the sending task.
+ *	@from contains the struct cred for the sending process.
  *	@file contains the struct file being transferred.
- *	@to contains the task_struct for the receiving task.
+ *	@to contains the struct cred for the receiving process.
  *
  * @ptrace_access_check:
  *	Check permission before allowing the current process to trace the
@@ -1338,13 +1342,13 @@
  */
 
 union security_list_options {
-	int (*binder_set_context_mgr)(struct task_struct *mgr);
-	int (*binder_transaction)(struct task_struct *from,
-					struct task_struct *to);
-	int (*binder_transfer_binder)(struct task_struct *from,
-					struct task_struct *to);
-	int (*binder_transfer_file)(struct task_struct *from,
-					struct task_struct *to,
+	int (*binder_set_context_mgr)(const struct cred *mgr);
+	int (*binder_transaction)(const struct cred *from,
+					const struct cred *to);
+	int (*binder_transfer_binder)(const struct cred *from,
+					const struct cred *to);
+	int (*binder_transfer_file)(const struct cred *from,
+					const struct cred *to,
 					struct file *file);
 
 	int (*ptrace_access_check)(struct task_struct *child,
@@ -1488,6 +1492,7 @@ union security_list_options {
 	int (*cred_prepare)(struct cred *new, const struct cred *old,
 				gfp_t gfp);
 	void (*cred_transfer)(struct cred *new, const struct cred *old);
+	void (*cred_getsecid)(const struct cred *c, u32 *secid);
 	int (*kernel_act_as)(struct cred *new, u32 secid);
 	int (*kernel_create_files_as)(struct cred *new, struct inode *inode);
 	int (*kernel_fw_from_file)(struct file *file, char *buf, size_t size);
@@ -1762,6 +1767,7 @@ struct security_hook_heads {
 	struct list_head cred_free;
 	struct list_head cred_prepare;
 	struct list_head cred_transfer;
+	struct list_head cred_getsecid;
 	struct list_head kernel_act_as;
 	struct list_head kernel_create_files_as;
 	struct list_head kernel_fw_from_file;
@@ -1943,6 +1949,13 @@ static inline void security_delete_hooks(struct security_hook_list *hooks,
 }
 #endif /* CONFIG_SECURITY_SELINUX_DISABLE */
 
+/* Currently required to handle SELinux runtime hook disable. */
+#ifdef CONFIG_SECURITY_WRITABLE_HOOKS
+#define __lsm_ro_after_init
+#else
+#define __lsm_ro_after_init	__ro_after_init
+#endif /* CONFIG_SECURITY_WRITABLE_HOOKS */
+
 extern int __init security_module_enable(const char *module);
 extern void __init capability_add_hooks(void);
 #ifdef CONFIG_SECURITY_YAMA

include/linux/security.h

@@ -184,13 +184,13 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
 extern int security_init(void);
 
 /* Security operations */
-int security_binder_set_context_mgr(struct task_struct *mgr);
-int security_binder_transaction(struct task_struct *from,
-				struct task_struct *to);
-int security_binder_transfer_binder(struct task_struct *from,
-				    struct task_struct *to);
-int security_binder_transfer_file(struct task_struct *from,
-				  struct task_struct *to, struct file *file);
+int security_binder_set_context_mgr(const struct cred *mgr);
+int security_binder_transaction(const struct cred *from,
+				const struct cred *to);
+int security_binder_transfer_binder(const struct cred *from,
+				    const struct cred *to);
+int security_binder_transfer_file(const struct cred *from,
+				  const struct cred *to, struct file *file);
 int security_ptrace_access_check(struct task_struct *child, unsigned int mode);
 int security_ptrace_traceme(struct task_struct *parent);
 int security_capget(struct task_struct *target,
@@ -299,6 +299,7 @@ int security_cred_alloc_blank(struct cred *cred, gfp_t gfp);
 void security_cred_free(struct cred *cred);
 int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp);
 void security_transfer_creds(struct cred *new, const struct cred *old);
+void security_cred_getsecid(const struct cred *c, u32 *secid);
 int security_kernel_act_as(struct cred *new, u32 secid);
 int security_kernel_create_files_as(struct cred *new, struct inode *inode);
 int security_kernel_fw_from_file(struct file *file, char *buf, size_t size);
@@ -382,25 +383,25 @@ static inline int security_init(void)
 	return 0;
 }
 
-static inline int security_binder_set_context_mgr(struct task_struct *mgr)
+static inline int security_binder_set_context_mgr(const struct cred *mgr)
 {
 	return 0;
 }
 
-static inline int security_binder_transaction(struct task_struct *from,
-					      struct task_struct *to)
+static inline int security_binder_transaction(const struct cred *from,
+					      const struct cred *to)
 {
 	return 0;
 }
 
-static inline int security_binder_transfer_binder(struct task_struct *from,
-						  struct task_struct *to)
+static inline int security_binder_transfer_binder(const struct cred *from,
+						  const struct cred *to)
 {
 	return 0;
 }
 
-static inline int security_binder_transfer_file(struct task_struct *from,
-						struct task_struct *to,
+static inline int security_binder_transfer_file(const struct cred *from,
+						const struct cred *to,
 						struct file *file)
 {
 	return 0;
@@ -849,6 +850,11 @@ static inline void security_transfer_creds(struct cred *new,
 {
 }
 
+static inline void security_cred_getsecid(const struct cred *c, u32 *secid)
+{
+	*secid = 0;
+}
+
 static inline int security_kernel_act_as(struct cred *cred, u32 secid)
 {
 	return 0;

net/ipv4/ip_gre.c

@@ -502,6 +502,10 @@ static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
 static struct sk_buff *gre_handle_offloads(struct sk_buff *skb,
 					   bool csum)
 {
+	unsigned char *skb_checksum_start = skb->head + skb->csum_start;
+
+	if (csum && skb_checksum_start < skb->data)
+		return ERR_PTR(-EINVAL);
 	return iptunnel_handle_offloads(skb, csum,
 					csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE);
 }

security/Kconfig

@@ -45,6 +45,11 @@ config SECURITY
 
 	  If you are unsure how to answer this question, answer N.
 
+config SECURITY_WRITABLE_HOOKS
+	depends on SECURITY
+	bool
+	default n
+
 config PAGE_TABLE_ISOLATION
 	bool "Remove the kernel mapping in user mode"
 	default y

security/apparmor/lsm.c

@@ -605,7 +605,7 @@ static int apparmor_task_setrlimit(struct task_struct *task,
 	return error;
 }
 
-static struct security_hook_list apparmor_hooks[] = {
+static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check),
 	LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme),
 	LSM_HOOK_INIT(capget, apparmor_capget),

security/commoncap.c

@@ -1081,7 +1081,7 @@ int cap_mmap_file(struct file *file, unsigned long reqprot,
 
 #ifdef CONFIG_SECURITY
 
-struct security_hook_list capability_hooks[] = {
+struct security_hook_list capability_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(capable, cap_capable),
 	LSM_HOOK_INIT(settime, cap_settime),
 	LSM_HOOK_INIT(ptrace_access_check, cap_ptrace_access_check),