2335c9cb83
Add the STACKLEAK gcc plugin to arm32 by adding the helper used by stackleak common code: on_thread_stack(). It initialize the stack with the poison value before returning from system calls which improves the kernel security. Additionally, this disables the plugin in EFI stub code and decompress code, which are out of scope for the protection. Before the test on Qemu versatilepb board: # echo STACKLEAK_ERASING > /sys/kernel/debug/provoke-crash/DIRECT lkdtm: Performing direct entry STACKLEAK_ERASING lkdtm: XFAIL: stackleak is not supported on this arch (HAVE_ARCH_STACKLEAK=n) After: # echo STACKLEAK_ERASING > /sys/kernel/debug/provoke-crash/DIRECT lkdtm: Performing direct entry STACKLEAK_ERASING lkdtm: stackleak stack usage: high offset: 80 bytes current: 280 bytes lowest: 696 bytes tracked: 696 bytes untracked: 192 bytes poisoned: 7220 bytes low offset: 4 bytes lkdtm: OK: the rest of the thread stack is properly erased Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
60 lines
1.5 KiB
C
60 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_STACKTRACE_H
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#define __ASM_STACKTRACE_H
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#include <asm/ptrace.h>
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#include <linux/llist.h>
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struct stackframe {
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/*
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* FP member should hold R7 when CONFIG_THUMB2_KERNEL is enabled
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* and R11 otherwise.
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*/
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unsigned long fp;
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unsigned long sp;
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unsigned long lr;
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unsigned long pc;
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/* address of the LR value on the stack */
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unsigned long *lr_addr;
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#ifdef CONFIG_KRETPROBES
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struct llist_node *kr_cur;
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struct task_struct *tsk;
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#endif
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#ifdef CONFIG_UNWINDER_FRAME_POINTER
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bool ex_frame;
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#endif
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};
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static inline bool on_thread_stack(void)
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{
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unsigned long delta = current_stack_pointer ^ (unsigned long)current->stack;
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return delta < THREAD_SIZE;
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}
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static __always_inline
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void arm_get_current_stackframe(struct pt_regs *regs, struct stackframe *frame)
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{
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frame->fp = frame_pointer(regs);
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frame->sp = regs->ARM_sp;
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frame->lr = regs->ARM_lr;
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frame->pc = regs->ARM_pc;
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#ifdef CONFIG_KRETPROBES
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frame->kr_cur = NULL;
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frame->tsk = current;
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#endif
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#ifdef CONFIG_UNWINDER_FRAME_POINTER
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frame->ex_frame = in_entry_text(frame->pc);
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#endif
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}
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extern int unwind_frame(struct stackframe *frame);
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extern void walk_stackframe(struct stackframe *frame,
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bool (*fn)(void *, unsigned long), void *data);
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extern void dump_mem(const char *lvl, const char *str, unsigned long bottom,
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unsigned long top);
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extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
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const char *loglvl);
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#endif /* __ASM_STACKTRACE_H */
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