[GIT pull] x86/urgent for v5.15-rc3

From: Thomas Gleixner
Date: Sun Sep 26 2021 - 06:34:18 EST


Linus,

please pull the latest x86/urgent branch from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-urgent-2021-09-26

up to: 5ba1071f7554: x86/insn, tools/x86: Fix undefined behavior due to potential unaligned accesses


A set of fixes for X86:

- Prevent sending the wrong signal when protection keys are enabled and
the kernel handles a fault in the vsyscall emulation.

- Invoke early_reserve_memory() before invoking e820_memory_setup() which
is required to make the Xen dom0 e820 hooks work correctly.

- Use the correct data type for the SETZ operand in the EMQCMDS
instruction wrapper.

- Prevent undefined behaviour to the potential unaligned accesss in the
instroction decoder library.

Thanks,

tglx

------------------>
Jiashuo Liang (1):
x86/fault: Fix wrong signal when vsyscall fails with pkey

Juergen Gross (1):
x86/setup: Call early_reserve_memory() earlier

Kees Cook (1):
x86/asm: Fix SETZ size enqcmds() build failure

Numfor Mbiziwo-Tiapo (1):
x86/insn, tools/x86: Fix undefined behavior due to potential unaligned accesses


arch/x86/include/asm/pkeys.h | 2 --
arch/x86/include/asm/special_insns.h | 2 +-
arch/x86/kernel/setup.c | 26 ++++++++++++++------------
arch/x86/lib/insn.c | 4 ++--
arch/x86/mm/fault.c | 26 ++++++++++++++++++--------
include/linux/pkeys.h | 2 ++
tools/arch/x86/lib/insn.c | 4 ++--
7 files changed, 39 insertions(+), 27 deletions(-)

diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h
index 5c7bcaa79623..1d5f14aff5f6 100644
--- a/arch/x86/include/asm/pkeys.h
+++ b/arch/x86/include/asm/pkeys.h
@@ -2,8 +2,6 @@
#ifndef _ASM_X86_PKEYS_H
#define _ASM_X86_PKEYS_H

-#define ARCH_DEFAULT_PKEY 0
-
/*
* If more than 16 keys are ever supported, a thorough audit
* will be necessary to ensure that the types that store key
diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h
index f3fbb84ff8a7..68c257a3de0d 100644
--- a/arch/x86/include/asm/special_insns.h
+++ b/arch/x86/include/asm/special_insns.h
@@ -275,7 +275,7 @@ static inline int enqcmds(void __iomem *dst, const void *src)
{
const struct { char _[64]; } *__src = src;
struct { char _[64]; } __iomem *__dst = dst;
- int zf;
+ bool zf;

/*
* ENQCMDS %(rdx), rax
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 79f164141116..40ed44ead063 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -830,6 +830,20 @@ void __init setup_arch(char **cmdline_p)

x86_init.oem.arch_setup();

+ /*
+ * Do some memory reservations *before* memory is added to memblock, so
+ * memblock allocations won't overwrite it.
+ *
+ * After this point, everything still needed from the boot loader or
+ * firmware or kernel text should be early reserved or marked not RAM in
+ * e820. All other memory is free game.
+ *
+ * This call needs to happen before e820__memory_setup() which calls the
+ * xen_memory_setup() on Xen dom0 which relies on the fact that those
+ * early reservations have happened already.
+ */
+ early_reserve_memory();
+
iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1;
e820__memory_setup();
parse_setup_data();
@@ -876,18 +890,6 @@ void __init setup_arch(char **cmdline_p)

parse_early_param();

- /*
- * Do some memory reservations *before* memory is added to
- * memblock, so memblock allocations won't overwrite it.
- * Do it after early param, so we could get (unlikely) panic from
- * serial.
- *
- * After this point everything still needed from the boot loader or
- * firmware or kernel text should be early reserved or marked not
- * RAM in e820. All other memory is free game.
- */
- early_reserve_memory();
-
#ifdef CONFIG_MEMORY_HOTPLUG
/*
* Memory used by the kernel cannot be hot-removed because Linux
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
index 058f19b20465..c565def611e2 100644
--- a/arch/x86/lib/insn.c
+++ b/arch/x86/lib/insn.c
@@ -37,10 +37,10 @@
((insn)->next_byte + sizeof(t) + n <= (insn)->end_kaddr)

#define __get_next(t, insn) \
- ({ t r = *(t*)insn->next_byte; insn->next_byte += sizeof(t); leXX_to_cpu(t, r); })
+ ({ t r; memcpy(&r, insn->next_byte, sizeof(t)); insn->next_byte += sizeof(t); leXX_to_cpu(t, r); })

#define __peek_nbyte_next(t, insn, n) \
- ({ t r = *(t*)((insn)->next_byte + n); leXX_to_cpu(t, r); })
+ ({ t r; memcpy(&r, (insn)->next_byte + n, sizeof(t)); leXX_to_cpu(t, r); })

#define get_next(t, insn) \
({ if (unlikely(!validate_next(t, insn, 0))) goto err_out; __get_next(t, insn); })
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index b2eefdefc108..84a2c8c4af73 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -710,7 +710,8 @@ page_fault_oops(struct pt_regs *regs, unsigned long error_code,

static noinline void
kernelmode_fixup_or_oops(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, int signal, int si_code)
+ unsigned long address, int signal, int si_code,
+ u32 pkey)
{
WARN_ON_ONCE(user_mode(regs));

@@ -735,8 +736,12 @@ kernelmode_fixup_or_oops(struct pt_regs *regs, unsigned long error_code,

set_signal_archinfo(address, error_code);

- /* XXX: hwpoison faults will set the wrong code. */
- force_sig_fault(signal, si_code, (void __user *)address);
+ if (si_code == SEGV_PKUERR) {
+ force_sig_pkuerr((void __user *)address, pkey);
+ } else {
+ /* XXX: hwpoison faults will set the wrong code. */
+ force_sig_fault(signal, si_code, (void __user *)address);
+ }
}

/*
@@ -798,7 +803,8 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
struct task_struct *tsk = current;

if (!user_mode(regs)) {
- kernelmode_fixup_or_oops(regs, error_code, address, pkey, si_code);
+ kernelmode_fixup_or_oops(regs, error_code, address,
+ SIGSEGV, si_code, pkey);
return;
}

@@ -930,7 +936,8 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
{
/* Kernel mode? Handle exceptions or die: */
if (!user_mode(regs)) {
- kernelmode_fixup_or_oops(regs, error_code, address, SIGBUS, BUS_ADRERR);
+ kernelmode_fixup_or_oops(regs, error_code, address,
+ SIGBUS, BUS_ADRERR, ARCH_DEFAULT_PKEY);
return;
}

@@ -1396,7 +1403,8 @@ void do_user_addr_fault(struct pt_regs *regs,
*/
if (!user_mode(regs))
kernelmode_fixup_or_oops(regs, error_code, address,
- SIGBUS, BUS_ADRERR);
+ SIGBUS, BUS_ADRERR,
+ ARCH_DEFAULT_PKEY);
return;
}

@@ -1416,7 +1424,8 @@ void do_user_addr_fault(struct pt_regs *regs,
return;

if (fatal_signal_pending(current) && !user_mode(regs)) {
- kernelmode_fixup_or_oops(regs, error_code, address, 0, 0);
+ kernelmode_fixup_or_oops(regs, error_code, address,
+ 0, 0, ARCH_DEFAULT_PKEY);
return;
}

@@ -1424,7 +1433,8 @@ void do_user_addr_fault(struct pt_regs *regs,
/* Kernel mode? Handle exceptions or die: */
if (!user_mode(regs)) {
kernelmode_fixup_or_oops(regs, error_code, address,
- SIGSEGV, SEGV_MAPERR);
+ SIGSEGV, SEGV_MAPERR,
+ ARCH_DEFAULT_PKEY);
return;
}

diff --git a/include/linux/pkeys.h b/include/linux/pkeys.h
index 6beb26b7151d..86be8bf27b41 100644
--- a/include/linux/pkeys.h
+++ b/include/linux/pkeys.h
@@ -4,6 +4,8 @@

#include <linux/mm.h>

+#define ARCH_DEFAULT_PKEY 0
+
#ifdef CONFIG_ARCH_HAS_PKEYS
#include <asm/pkeys.h>
#else /* ! CONFIG_ARCH_HAS_PKEYS */
diff --git a/tools/arch/x86/lib/insn.c b/tools/arch/x86/lib/insn.c
index c41f95815480..797699462cd8 100644
--- a/tools/arch/x86/lib/insn.c
+++ b/tools/arch/x86/lib/insn.c
@@ -37,10 +37,10 @@
((insn)->next_byte + sizeof(t) + n <= (insn)->end_kaddr)

#define __get_next(t, insn) \
- ({ t r = *(t*)insn->next_byte; insn->next_byte += sizeof(t); leXX_to_cpu(t, r); })
+ ({ t r; memcpy(&r, insn->next_byte, sizeof(t)); insn->next_byte += sizeof(t); leXX_to_cpu(t, r); })

#define __peek_nbyte_next(t, insn, n) \
- ({ t r = *(t*)((insn)->next_byte + n); leXX_to_cpu(t, r); })
+ ({ t r; memcpy(&r, (insn)->next_byte + n, sizeof(t)); leXX_to_cpu(t, r); })

#define get_next(t, insn) \
({ if (unlikely(!validate_next(t, insn, 0))) goto err_out; __get_next(t, insn); })