[Devel] [PATCH RHEL7 COMMIT] ms/x86/signal: add SA_{X32, IA32}_ABI sa_flags
Konstantin Khorenko
khorenko at virtuozzo.com
Thu Aug 11 02:28:04 PDT 2016
The commit is pushed to "branch-rh7-3.10.0-327.22.2.vz7.16.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-327.22.2.vz7.16.5
------>
commit 9068957cdbebe6e07941f732de50e944b2a53a3a
Author: Dmitry Safonov <dsafonov at virtuozzo.com>
Date: Thu Aug 11 13:28:04 2016 +0400
ms/x86/signal: add SA_{X32,IA32}_ABI sa_flags
Introduce new flags that defines which ABI to use on creating sigframe.
Those flags kernel will set according to sigaction syscall ABI,
which set handler for the signal being delivered.
So that will drop the dependency on TIF_IA32/TIF_X32 flags on signal deliver.
Those flags will be used only under CONFIG_COMPAT.
Similar way ARM uses sa_flags to differ in which mode deliver signal
for 26-bit applications (look at SA_THIRYTWO).
Cc: Oleg Nesterov <oleg at redhat.com>
Cc: Andy Lutomirski <luto at kernel.org>
Cc: Ingo Molnar <mingo at redhat.com>
Cc: Cyrill Gorcunov <gorcunov at openvz.org>
Cc: Pavel Emelyanov <xemul at virtuozzo.com>
Cc: x86 at kernel.org
Signed-off-by: Dmitry Safonov <dsafonov at virtuozzo.com>
Reviewed-by: Andy Lutomirski <luto at kernel.org>
[backport notes: left non-const argument for copy_siginfo_to_user32(),
x86-specific code in v4.6 differs with v3.10 by file-location mostly,
didn't port my patch about renaming is_{ia32,x32}_task to
in_{ia32,x32}_syscall.]
Signed-off-by: Dmitry Safonov <dsafonov at virtuozzo.com>
---
arch/x86/ia32/ia32_signal.c | 36 ++++++++++++++++++++++++++++++++----
arch/x86/include/asm/fpu-internal.h | 20 ++++++++++++++------
arch/x86/include/asm/signal.h | 4 ++++
arch/x86/kernel/signal.c | 6 +++---
kernel/signal.c | 7 +++++++
5 files changed, 60 insertions(+), 13 deletions(-)
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 665a730..9c6c4de 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -19,6 +19,7 @@
#include <linux/personality.h>
#include <linux/compat.h>
#include <linux/binfmts.h>
+#include <linux/ptrace.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/i387.h>
@@ -34,10 +35,31 @@
#include <asm/sys_ia32.h>
#include <asm/smap.h>
-int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
+void sigaction_compat_abi(struct k_sigaction *act, struct k_sigaction *oact)
+{
+ /* Don't leak in-kernel non-uapi flags to user-space */
+ if (oact)
+ oact->sa.sa_flags &= ~(SA_IA32_ABI | SA_X32_ABI);
+
+ if (!act)
+ return;
+
+ /* Don't let flags to be set from userspace */
+ act->sa.sa_flags &= ~(SA_IA32_ABI | SA_X32_ABI);
+
+ if (user_64bit_mode(current_pt_regs()))
+ return;
+
+ if (is_ia32_task())
+ act->sa.sa_flags |= SA_IA32_ABI;
+ if (is_x32_task())
+ act->sa.sa_flags |= SA_X32_ABI;
+}
+
+int __copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from,
+ bool x32_ABI)
{
int err = 0;
- bool ia32 = test_thread_flag(TIF_IA32);
if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t)))
return -EFAULT;
@@ -71,7 +93,7 @@ int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
put_user_ex(from->si_arch, &to->si_arch);
break;
case __SI_CHLD >> 16:
- if (ia32) {
+ if (!x32_ABI) {
put_user_ex(from->si_utime, &to->si_utime);
put_user_ex(from->si_stime, &to->si_stime);
} else {
@@ -105,6 +127,12 @@ int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
return err;
}
+/* from syscall's path, where we know the ABI */
+int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
+{
+ return __copy_siginfo_to_user32(to, from, is_x32_task());
+}
+
int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
{
int err = 0;
@@ -473,7 +501,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
put_user_ex(*((u64 *)&code), (u64 __user *)frame->retcode);
} put_user_catch(err);
- err |= copy_siginfo_to_user32(&frame->info, &ksig->info);
+ err |= __copy_siginfo_to_user32(&frame->info, &ksig->info, false);
err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
regs, set->sig[0]);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
index e72b2e4..3581c95 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -22,6 +22,7 @@
#include <asm/uaccess.h>
#include <asm/xsave.h>
#include <asm/smap.h>
+#include <asm/signal.h>
#ifdef CONFIG_X86_64
# include <asm/sigcontext32.h>
@@ -38,6 +39,12 @@ int ia32_setup_frame(int sig, struct ksignal *ksig,
# define ia32_setup_rt_frame __setup_rt_frame
#endif
+#ifdef CONFIG_COMPAT
+int __copy_siginfo_to_user32(compat_siginfo_t __user *to,
+ const siginfo_t *from, bool x32_ABI);
+#endif
+
+
extern unsigned int mxcsr_feature_mask;
extern void fpu_init(void);
extern void eager_fpu_init(void);
@@ -69,20 +76,21 @@ extern void finit_soft_fpu(struct i387_soft_struct *soft);
static inline void finit_soft_fpu(struct i387_soft_struct *soft) {}
#endif
-static inline int is_ia32_compat_frame(void)
+static inline int is_ia32_compat_frame(struct ksignal *ksig)
{
return config_enabled(CONFIG_IA32_EMULATION) &&
- test_thread_flag(TIF_IA32);
+ ksig->ka.sa.sa_flags & SA_IA32_ABI;
}
-static inline int is_ia32_frame(void)
+static inline int is_ia32_frame(struct ksignal *ksig)
{
- return config_enabled(CONFIG_X86_32) || is_ia32_compat_frame();
+ return config_enabled(CONFIG_X86_32) || is_ia32_compat_frame(ksig);
}
-static inline int is_x32_frame(void)
+static inline int is_x32_frame(struct ksignal *ksig)
{
- return config_enabled(CONFIG_X86_X32_ABI) && test_thread_flag(TIF_X32);
+ return config_enabled(CONFIG_X86_X32_ABI) &&
+ ksig->ka.sa.sa_flags & SA_X32_ABI;
}
#define X87_FSW_ES (1 << 7) /* Exception Summary */
diff --git a/arch/x86/include/asm/signal.h b/arch/x86/include/asm/signal.h
index 35e67a4..c5b8f73 100644
--- a/arch/x86/include/asm/signal.h
+++ b/arch/x86/include/asm/signal.h
@@ -23,6 +23,10 @@ typedef struct {
unsigned long sig[_NSIG_WORDS];
} sigset_t;
+/* non-uapi in-kernel SA_FLAGS for those indicates ABI for a signal frame */
+#define SA_IA32_ABI 0x02000000u
+#define SA_X32_ABI 0x01000000u
+
#ifndef CONFIG_COMPAT
typedef sigset_t compat_sigset_t;
#endif
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 008732a..a3e0bca 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -479,7 +479,7 @@ static int x32_setup_rt_frame(struct ksignal *ksig,
return -EFAULT;
if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
- if (copy_siginfo_to_user32(&frame->info, &ksig->info))
+ if (__copy_siginfo_to_user32(&frame->info, &ksig->info, true))
return -EFAULT;
}
@@ -612,12 +612,12 @@ setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
compat_sigset_t *cset = (compat_sigset_t *) set;
/* Set up the stack frame */
- if (is_ia32_frame()) {
+ if (is_ia32_frame(ksig)) {
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
return ia32_setup_rt_frame(usig, ksig, cset, regs);
else
return ia32_setup_frame(usig, ksig, cset, regs);
- } else if (is_x32_frame()) {
+ } else if (is_x32_frame(ksig)) {
return x32_setup_rt_frame(ksig, cset, regs);
} else {
return __setup_rt_frame(ksig->sig, ksig, set, regs);
diff --git a/kernel/signal.c b/kernel/signal.c
index 49fbdb0..6793dd5 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3109,6 +3109,11 @@ COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
}
#endif
+void __weak sigaction_compat_abi(struct k_sigaction *act,
+ struct k_sigaction *oact)
+{
+}
+
int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
{
struct task_struct *t = current;
@@ -3124,6 +3129,8 @@ int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
if (oact)
*oact = *k;
+ sigaction_compat_abi(act, oact);
+
if (act) {
sigdelsetmask(&act->sa.sa_mask,
sigmask(SIGKILL) | sigmask(SIGSTOP));
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