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Commit 53290432 authored by Will Deacon's avatar Will Deacon
Browse files

arm64: compat: Don't pull syscall number from regs in arm_compat_syscall 



The syscall number may have been changed by a tracer, so we should pass
the actual number in from the caller instead of pulling it from the
saved r7 value directly.

Cc: <stable@vger.kernel.org>
Cc: Pi-Hsun Shih <pihsun@chromium.org>
Reviewed-by: default avatarDave Martin <Dave.Martin@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 169113ec

arch/arm64/kernel/sys_compat.c

+4 −5
Original line number Diff line number Diff line
@@ -66,12 +66,11 @@ do_compat_cache_op(unsigned long start, unsigned long end, int flags) 
/*

 * Handle all unrecognised system calls.

 */

long compat_arm_syscall(struct pt_regs *regs)

long compat_arm_syscall(struct pt_regs *regs, int scno)

{

	unsigned int no = regs->regs[7];

	void __user *addr;



	switch (no) {

	switch (scno) {

	/*

	 * Flush a region from virtual address 'r0' to virtual address 'r1'

	 * _exclusive_.  There is no alignment requirement on either address;
@@ -107,7 +106,7 @@ long compat_arm_syscall(struct pt_regs *regs) 
		 * way the calling program can gracefully determine whether

		 * a feature is supported.

		 */

		if (no < __ARM_NR_COMPAT_END)

		if (scno < __ARM_NR_COMPAT_END)

			return -ENOSYS;

		break;

	}
@@ -116,6 +115,6 @@ long compat_arm_syscall(struct pt_regs *regs) 
		(compat_thumb_mode(regs) ? 2 : 4);



	arm64_notify_die("Oops - bad compat syscall(2)", regs,

			 SIGILL, ILL_ILLTRP, addr, no);

			 SIGILL, ILL_ILLTRP, addr, scno);

	return 0;

}

arch/arm64/kernel/syscall.c

+4 −5
Original line number Diff line number Diff line
@@ -13,16 +13,15 @@ 
#include <asm/thread_info.h>

#include <asm/unistd.h>



long compat_arm_syscall(struct pt_regs *regs);



long compat_arm_syscall(struct pt_regs *regs, int scno);

long sys_ni_syscall(void);



asmlinkage long do_ni_syscall(struct pt_regs *regs)

static long do_ni_syscall(struct pt_regs *regs, int scno)

{

#ifdef CONFIG_COMPAT

	long ret;

	if (is_compat_task()) {

		ret = compat_arm_syscall(regs);

		ret = compat_arm_syscall(regs, scno);

		if (ret != -ENOSYS)

			return ret;

	}
@@ -47,7 +46,7 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno, 
		syscall_fn = syscall_table[array_index_nospec(scno, sc_nr)];

		ret = __invoke_syscall(regs, syscall_fn);

	} else {

		ret = do_ni_syscall(regs);

		ret = do_ni_syscall(regs, scno);

	}



	regs->regs[0] = ret;