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

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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: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Will Deacon 2019-01-03 18:00:39 +00:00
parent 169113ece0
commit 5329043214
2 changed files with 8 additions and 10 deletions
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9
arch/arm64/kernel/sys_compat.c
View File

@ -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;
}

9
arch/arm64/kernel/syscall.c
View File

@ -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;