From: Lai Jiangshan <jiangshanlai@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: x86@kernel.org, Lai Jiangshan <laijs@linux.alibaba.com>,
Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>, Oleg Nesterov <oleg@redhat.com>,
"Chang S. Bae" <chang.seok.bae@intel.com>,
Jan Kiszka <jan.kiszka@siemens.com>,
Joerg Roedel <jroedel@suse.de>
Subject: [PATCH 3/3] x86/sev: The code for returning to user space is also in syscall gap
Date: Mon, 13 Dec 2021 12:22:15 +0800 [thread overview]
Message-ID: <20211213042215.3096-4-jiangshanlai@gmail.com> (raw)
In-Reply-To: <20211213042215.3096-1-jiangshanlai@gmail.com>
From: Lai Jiangshan <laijs@linux.alibaba.com>
When returning to user space, the %rsp is user controlled value.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
arch/x86/entry/entry_64.S | 2 ++
arch/x86/entry/entry_64_compat.S | 2 ++
arch/x86/include/asm/proto.h | 4 ++++
arch/x86/include/asm/ptrace.h | 4 ++++
4 files changed, 12 insertions(+)
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index e23319ad3f42..44dadea935f7 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -213,8 +213,10 @@ syscall_return_via_sysret:
popq %rdi
popq %rsp
+SYM_INNER_LABEL(entry_SYSRETQ_unsafe_stack, SYM_L_GLOBAL)
swapgs
sysretq
+SYM_INNER_LABEL(entry_SYSRETQ_end, SYM_L_GLOBAL)
SYM_CODE_END(entry_SYSCALL_64)
/*
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index 0051cf5c792d..98afdf92f360 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -293,6 +293,7 @@ sysret32_from_system_call:
* code. We zero R8-R10 to avoid info leaks.
*/
movq RSP-ORIG_RAX(%rsp), %rsp
+SYM_INNER_LABEL(entry_SYSRETL_compat_unsafe_stack, SYM_L_GLOBAL)
/*
* The original userspace %rsp (RSP-ORIG_RAX(%rsp)) is stored
@@ -310,6 +311,7 @@ sysret32_from_system_call:
xorl %r10d, %r10d
swapgs
sysretl
+SYM_INNER_LABEL(entry_SYSRETL_compat_end, SYM_L_GLOBAL)
SYM_CODE_END(entry_SYSCALL_compat)
/*
diff --git a/arch/x86/include/asm/proto.h b/arch/x86/include/asm/proto.h
index feed36d44d04..f042cfc9938f 100644
--- a/arch/x86/include/asm/proto.h
+++ b/arch/x86/include/asm/proto.h
@@ -13,6 +13,8 @@ void syscall_init(void);
#ifdef CONFIG_X86_64
void entry_SYSCALL_64(void);
void entry_SYSCALL_64_safe_stack(void);
+void entry_SYSRETQ_unsafe_stack(void);
+void entry_SYSRETQ_end(void);
long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2);
#endif
@@ -28,6 +30,8 @@ void entry_SYSENTER_compat(void);
void __end_entry_SYSENTER_compat(void);
void entry_SYSCALL_compat(void);
void entry_SYSCALL_compat_safe_stack(void);
+void entry_SYSRETL_compat_unsafe_stack(void);
+void entry_SYSRETL_compat_end(void);
void entry_INT80_compat(void);
#ifdef CONFIG_XEN_PV
void xen_entry_INT80_compat(void);
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index 703663175a5a..b3d2ba13cee2 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -186,9 +186,13 @@ static __always_inline bool ip_within_syscall_gap(struct pt_regs *regs)
bool ret = (regs->ip >= (unsigned long)entry_SYSCALL_64 &&
regs->ip < (unsigned long)entry_SYSCALL_64_safe_stack);
+ ret = ret || (regs->ip >= (unsigned long)entry_SYSRETQ_unsafe_stack &&
+ regs->ip < (unsigned long)entry_SYSRETQ_end);
#ifdef CONFIG_IA32_EMULATION
ret = ret || (regs->ip >= (unsigned long)entry_SYSCALL_compat &&
regs->ip < (unsigned long)entry_SYSCALL_compat_safe_stack);
+ ret = ret || (regs->ip >= (unsigned long)entry_SYSRETL_compat_unsafe_stack &&
+ regs->ip < (unsigned long)entry_SYSRETL_compat_end);
#endif
return ret;
--
2.19.1.6.gb485710b
next prev parent reply other threads:[~2021-12-13 4:22 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-13 4:22 [PATCH 0/3] x86/entry: Fix 3 suspicious bugs Lai Jiangshan
2021-12-13 4:22 ` [PATCH 1/3] X86/db: Change __this_cpu_read() to this_cpu_read() in hw_breakpoint_active() Lai Jiangshan
2021-12-13 19:09 ` Borislav Petkov
2021-12-14 2:51 ` Lai Jiangshan
2021-12-14 9:33 ` Borislav Petkov
2021-12-13 19:46 ` Peter Zijlstra
2021-12-13 4:22 ` [PATCH 2/3] x86/hw_breakpoint: Add stack_canary to hw_breakpoints denylist Lai Jiangshan
2021-12-13 19:57 ` Peter Zijlstra
2021-12-13 4:22 ` Lai Jiangshan [this message]
2021-12-14 21:51 ` [PATCH 3/3] x86/sev: The code for returning to user space is also in syscall gap Borislav Petkov
2021-12-17 10:05 ` Joerg Roedel
2021-12-17 10:30 ` Borislav Petkov
2021-12-17 11:00 ` Joerg Roedel
2022-01-18 10:32 ` Borislav Petkov
2022-01-18 15:37 ` Lai Jiangshan
2022-04-12 13:00 ` Lai Jiangshan
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