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100 lines
3.1 KiB
100 lines
3.1 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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/* |
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* Return hooking with list-based shadow stack. |
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*/ |
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#ifndef _LINUX_RETHOOK_H |
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#define _LINUX_RETHOOK_H |
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#include <linux/compiler.h> |
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#include <linux/freelist.h> |
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#include <linux/kallsyms.h> |
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#include <linux/llist.h> |
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#include <linux/rcupdate.h> |
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#include <linux/refcount.h> |
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struct rethook_node; |
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typedef void (*rethook_handler_t) (struct rethook_node *, void *, struct pt_regs *); |
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/** |
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* struct rethook - The rethook management data structure. |
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* @data: The user-defined data storage. |
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* @handler: The user-defined return hook handler. |
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* @pool: The pool of struct rethook_node. |
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* @ref: The reference counter. |
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* @rcu: The rcu_head for deferred freeing. |
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* |
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* Don't embed to another data structure, because this is a self-destructive |
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* data structure when all rethook_node are freed. |
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*/ |
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struct rethook { |
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void *data; |
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rethook_handler_t handler; |
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struct freelist_head pool; |
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refcount_t ref; |
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struct rcu_head rcu; |
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}; |
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/** |
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* struct rethook_node - The rethook shadow-stack entry node. |
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* @freelist: The freelist, linked to struct rethook::pool. |
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* @rcu: The rcu_head for deferred freeing. |
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* @llist: The llist, linked to a struct task_struct::rethooks. |
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* @rethook: The pointer to the struct rethook. |
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* @ret_addr: The storage for the real return address. |
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* @frame: The storage for the frame pointer. |
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* |
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* You can embed this to your extended data structure to store any data |
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* on each entry of the shadow stack. |
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*/ |
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struct rethook_node { |
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union { |
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struct freelist_node freelist; |
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struct rcu_head rcu; |
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}; |
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struct llist_node llist; |
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struct rethook *rethook; |
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unsigned long ret_addr; |
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unsigned long frame; |
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}; |
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struct rethook *rethook_alloc(void *data, rethook_handler_t handler); |
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void rethook_free(struct rethook *rh); |
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void rethook_add_node(struct rethook *rh, struct rethook_node *node); |
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struct rethook_node *rethook_try_get(struct rethook *rh); |
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void rethook_recycle(struct rethook_node *node); |
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void rethook_hook(struct rethook_node *node, struct pt_regs *regs, bool mcount); |
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unsigned long rethook_find_ret_addr(struct task_struct *tsk, unsigned long frame, |
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struct llist_node **cur); |
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/* Arch dependent code must implement arch_* and trampoline code */ |
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void arch_rethook_prepare(struct rethook_node *node, struct pt_regs *regs, bool mcount); |
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void arch_rethook_trampoline(void); |
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/** |
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* is_rethook_trampoline() - Check whether the address is rethook trampoline |
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* @addr: The address to be checked |
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* |
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* Return true if the @addr is the rethook trampoline address. |
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*/ |
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static inline bool is_rethook_trampoline(unsigned long addr) |
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{ |
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return addr == (unsigned long)dereference_symbol_descriptor(arch_rethook_trampoline); |
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} |
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/* If the architecture needs to fixup the return address, implement it. */ |
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void arch_rethook_fixup_return(struct pt_regs *regs, |
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unsigned long correct_ret_addr); |
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/* Generic trampoline handler, arch code must prepare asm stub */ |
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unsigned long rethook_trampoline_handler(struct pt_regs *regs, |
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unsigned long frame); |
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#ifdef CONFIG_RETHOOK |
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void rethook_flush_task(struct task_struct *tk); |
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#else |
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#define rethook_flush_task(tsk) do { } while (0) |
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#endif |
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#endif |
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