On Mon, Jan 07, 2019 at 10:40:11AM +0100, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
>
> The patch below does not apply to the 4.19-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.
>
> thanks,
>
> greg k-h
>
> ------------------ original commit in Linus's tree ------------------
>
> From 53290432145a8eb143fe29e06e9c1465d43dc723 Mon Sep 17 00:00:00 2001
> From: Will Deacon <will.deacon@xxxxxxx>
> Date: Thu, 3 Jan 2019 18:00:39 +0000
> Subject: [PATCH] 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.
Fixed patch below. I don't think we need to consider kernels prior to 4.19.
Will
--->8
>From 7e5f7c4e6fd50fe216fa53d9343141fbf1547a10 Mon Sep 17 00:00:00 2001
From: Will Deacon <will.deacon@xxxxxxx>
Date: Thu, 3 Jan 2019 18:00:39 +0000
Subject: [PATCH] arm64: compat: Don't pull syscall number from regs in
arm_compat_syscall
Commit 53290432145a8eb143fe29e06e9c1465d43dc723 upstream.
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@xxxxxxxxxxxxxxx> # 4.19
Cc: Pi-Hsun Shih <pihsun@xxxxxxxxxxxx>
Reviewed-by: Dave Martin <Dave.Martin@xxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
---
arch/arm64/kernel/sys_compat.c | 9 ++++-----
arch/arm64/kernel/syscall.c | 9 ++++-----
2 files changed, 8 insertions(+), 10 deletions(-)
diff --git a/arch/arm64/kernel/sys_compat.c b/arch/arm64/kernel/sys_compat.c
index 7be666062c7c..010212d35700 100644
--- a/arch/arm64/kernel/sys_compat.c
+++ b/arch/arm64/kernel/sys_compat.c
@@ -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)
{
siginfo_t info;
- unsigned int no = regs->regs[7];
- 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;
}
@@ -119,6 +118,6 @@ long compat_arm_syscall(struct pt_regs *regs)
info.si_addr = (void __user *)instruction_pointer(regs) -
(compat_thumb_mode(regs) ? 2 : 4);
- arm64_notify_die("Oops - bad compat syscall(2)", regs, &info, no);
+ arm64_notify_die("Oops - bad compat syscall(2)", regs, &info, scno);
return 0;
}
diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c
index 032d22312881..5610ac01c1ec 100644
--- a/arch/arm64/kernel/syscall.c
+++ b/arch/arm64/kernel/syscall.c
@@ -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;
--
2.11.0
