Commit 44a1d996 authored by Al Viro's avatar Al Viro
Browse files

x86: ia32_setup_sigcontext(): lift user_access_{begin,end}() into the callers 



What's left is just a sequence of stores to userland addresses, with all
error handling, etc. done out of line.  Calling that from user_access block
is safe, but rather than teaching objtool to recognize it as such we can
just make it always_inline - it is small enough and has few enough callers,
for the space savings not to be an issue.

	Rename the sucker to __unsafe_setup_sigcontext32() and provide
unsafe_put_sigcontext32() with usual kind of semantics.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 39f16c1c

arch/x86/ia32/ia32_signal.c

+28 −16
Original line number Diff line number Diff line
@@ -154,13 +154,11 @@ badframe: 


#define get_user_seg(seg)	({ unsigned int v; savesegment(seg, v); v; })



static int ia32_setup_sigcontext(struct sigcontext_32 __user *sc,

static __always_inline int

__unsafe_setup_sigcontext32(struct sigcontext_32 __user *sc,

			    void __user *fpstate,

			    struct pt_regs *regs, unsigned int mask)

{

	if (!user_access_begin(sc, sizeof(struct sigcontext_32)))

		return -EFAULT;



	unsafe_put_user(get_user_seg(gs), (unsigned int __user *)&sc->gs, Efault);

	unsafe_put_user(get_user_seg(fs), (unsigned int __user *)&sc->fs, Efault);

	unsafe_put_user(get_user_seg(ds), (unsigned int __user *)&sc->ds, Efault);
@@ -187,13 +185,18 @@ static int ia32_setup_sigcontext(struct sigcontext_32 __user *sc, 
	/* non-iBCS2 extensions.. */

	unsafe_put_user(mask, &sc->oldmask, Efault);

	unsafe_put_user(current->thread.cr2, &sc->cr2, Efault);

	user_access_end();

	return 0;



Efault:

	user_access_end();

	return -EFAULT;

}



#define unsafe_put_sigcontext32(sc, fp, regs, set, label)		\

do {									\

	if (__unsafe_setup_sigcontext32(sc, fp, regs, set->sig[0]))	\

		goto label;						\

} while(0)



/*

 * Determine which stack to use..

 */
@@ -234,7 +237,7 @@ int ia32_setup_frame(int sig, struct ksignal *ksig, 
	struct sigframe_ia32 __user *frame;

	void __user *restorer;

	int err = 0;

	void __user *fpstate = NULL;

	void __user *fp = NULL;



	/* copy_to_user optimizes that into a single 8 byte store */

	static const struct {
@@ -247,7 +250,7 @@ int ia32_setup_frame(int sig, struct ksignal *ksig, 
		0x80cd,		/* int $0x80 */

	};



	frame = get_sigframe(ksig, regs, sizeof(*frame), &fpstate);

	frame = get_sigframe(ksig, regs, sizeof(*frame), &fp);



	if (!access_ok(frame, sizeof(*frame)))

		return -EFAULT;
@@ -255,9 +258,12 @@ int ia32_setup_frame(int sig, struct ksignal *ksig, 
	if (__put_user(sig, &frame->sig))

		return -EFAULT;



	if (ia32_setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))

	if (!user_access_begin(&frame->sc, sizeof(struct sigcontext_32)))

		return -EFAULT;



	unsafe_put_sigcontext32(&frame->sc, fp, regs, set, Efault);

	user_access_end();



	if (__put_user(set->sig[1], &frame->extramask[0]))

		return -EFAULT;
@@ -301,6 +307,9 @@ int ia32_setup_frame(int sig, struct ksignal *ksig, 
	regs->ss = __USER32_DS;



	return 0;

Efault:

	user_access_end();

	return -EFAULT;

}



int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
@@ -309,7 +318,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig, 
	struct rt_sigframe_ia32 __user *frame;

	void __user *restorer;

	int err = 0;

	void __user *fpstate = NULL;

	void __user *fp = NULL;



	/* __copy_to_user optimizes that into a single 8 byte store */

	static const struct {
@@ -324,7 +333,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig, 
		0,

	};



	frame = get_sigframe(ksig, regs, sizeof(*frame), &fpstate);

	frame = get_sigframe(ksig, regs, sizeof(*frame), &fp);



	if (!user_access_begin(frame, sizeof(*frame)))

		return -EFAULT;
@@ -355,9 +364,12 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig, 
	unsafe_put_user(*((u64 *)&code), (u64 __user *)frame->retcode, Efault);

	user_access_end();



	err |= __copy_siginfo_to_user32(&frame->info, &ksig->info, false);

	err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate,

				     regs, set->sig[0]);

	if (__copy_siginfo_to_user32(&frame->info, &ksig->info, false))

		return -EFAULT;

	if (!user_access_begin(&frame->uc.uc_mcontext, sizeof(struct sigcontext_32)))

		return -EFAULT;

	unsafe_put_sigcontext32(&frame->uc.uc_mcontext, fp, regs, set, Efault);

	user_access_end();

	err |= __put_user(*(__u64 *)set, (__u64 __user *)&frame->uc.uc_sigmask);



	if (err)

CRA Git | Maintained and supported by SUSTech CRA and CCSE