Commit 9c36e592 authored by Brian Gerst's avatar Brian Gerst Committed by Borislav Petkov
Browse files

x86/signal: Merge get_sigframe() 



Adapt the native get_sigframe() function so that the compat signal code
can use it.

Signed-off-by: default avatarBrian Gerst <brgerst@gmail.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Acked-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Link: https://lore.kernel.org/r/20220606203802.158958-6-brgerst@gmail.com


Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
parent 695c39bc

arch/x86/ia32/ia32_signal.c

+0 −34
Original line number Diff line number Diff line
@@ -196,40 +196,6 @@ do { \ 
		goto label;						\

} while(0)



/*

 * Determine which stack to use..

 */

static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,

				 size_t frame_size,

				 void __user **fpstate)

{

	unsigned long sp, fx_aligned, math_size;



	/* Default to using normal stack */

	sp = regs->sp;



	/* This is the X/Open sanctioned signal stack switching.  */

	if (ksig->ka.sa.sa_flags & SA_ONSTACK)

		sp = sigsp(sp, ksig);

	/* This is the legacy signal stack switching. */

	else if (regs->ss != __USER_DS &&

		!(ksig->ka.sa.sa_flags & SA_RESTORER) &&

		 ksig->ka.sa.sa_restorer)

		sp = (unsigned long) ksig->ka.sa.sa_restorer;



	sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size);

	*fpstate = (struct _fpstate_32 __user *) sp;

	if (!copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned,

				      math_size))

		return (void __user *) -1L;



	sp -= frame_size;

	/* Align the stack pointer according to the i386 ABI,

	 * i.e. so that on function entry ((sp + 4) & 15) == 0. */

	sp = ((sp + 4) & -16ul) - 4;

	return (void __user *) sp;

}



int ia32_setup_frame(struct ksignal *ksig, struct pt_regs *regs)

{

	compat_sigset_t *set = (compat_sigset_t *) sigmask_to_save();

arch/x86/include/asm/sighandling.h

+4 −0
Original line number Diff line number Diff line
@@ -15,4 +15,8 @@ 


void signal_fault(struct pt_regs *regs, void __user *frame, char *where);



void __user *

get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size,

	     void __user **fpstate);



#endif /* _ASM_X86_SIGHANDLING_H */

arch/x86/kernel/signal.c

+38 −42
Original line number Diff line number Diff line
@@ -48,6 +48,23 @@ 
#include <asm/sigframe.h>

#include <asm/signal.h>



static inline int is_ia32_compat_frame(struct ksignal *ksig)

{

	return IS_ENABLED(CONFIG_IA32_EMULATION) &&

		ksig->ka.sa.sa_flags & SA_IA32_ABI;

}



static inline int is_ia32_frame(struct ksignal *ksig)

{

	return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame(ksig);

}



static inline int is_x32_frame(struct ksignal *ksig)

{

	return IS_ENABLED(CONFIG_X86_X32_ABI) &&

		ksig->ka.sa.sa_flags & SA_X32_ABI;

}



#ifdef CONFIG_X86_64

/*

 * If regs->ss will cause an IRET fault, change it.  Otherwise leave it
@@ -223,24 +240,12 @@ do { \ 
/*

 * Determine which stack to use..

 */

static unsigned long align_sigframe(unsigned long sp)

{

#ifdef CONFIG_X86_32

	/*

	 * Align the stack pointer according to the i386 ABI,

	 * i.e. so that on function entry ((sp + 4) & 15) == 0.

	 */

	sp = ((sp + 4) & -FRAME_ALIGNMENT) - 4;

#else /* !CONFIG_X86_32 */

	sp = round_down(sp, FRAME_ALIGNMENT) - 8;

#endif

	return sp;

}



static void __user *

get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,

void __user *

get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size,

	     void __user **fpstate)

{

	struct k_sigaction *ka = &ksig->ka;

	int ia32_frame = is_ia32_frame(ksig);

	/* Default to using normal stack */

	bool nested_altstack = on_sig_stack(regs->sp);

	bool entering_altstack = false;
@@ -249,7 +254,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, 
	unsigned long buf_fx = 0;



	/* redzone */

	if (IS_ENABLED(CONFIG_X86_64))

	if (!ia32_frame)

		sp -= 128;



	/* This is the X/Open sanctioned signal stack switching.  */
@@ -263,7 +268,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, 
			sp = current->sas_ss_sp + current->sas_ss_size;

			entering_altstack = true;

		}

	} else if (IS_ENABLED(CONFIG_X86_32) &&

	} else if (ia32_frame &&

		   !nested_altstack &&

		   regs->ss != __USER_DS &&

		   !(ka->sa.sa_flags & SA_RESTORER) &&
@@ -273,11 +278,19 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, 
		entering_altstack = true;

	}



	sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32),

				  &buf_fx, &math_size);

	sp = fpu__alloc_mathframe(sp, ia32_frame, &buf_fx, &math_size);

	*fpstate = (void __user *)sp;



	sp = align_sigframe(sp - frame_size);

	sp -= frame_size;



	if (ia32_frame)

		/*

		 * Align the stack pointer according to the i386 ABI,

		 * i.e. so that on function entry ((sp + 4) & 15) == 0.

		 */

		sp = ((sp + 4) & -FRAME_ALIGNMENT) - 4;

	else

		sp = round_down(sp, FRAME_ALIGNMENT) - 8;



	/*

	 * If we are on the alternate signal stack and would overflow it, don't.
@@ -331,7 +344,7 @@ __setup_frame(struct ksignal *ksig, struct pt_regs *regs) 
	void __user *restorer;

	void __user *fp = NULL;



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

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



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

		return -EFAULT;
@@ -386,7 +399,7 @@ static int __setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) 
	void __user *restorer;

	void __user *fp = NULL;



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

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



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

		return -EFAULT;
@@ -469,7 +482,7 @@ static int __setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) 
	if (!(ksig->ka.sa.sa_flags & SA_RESTORER))

		return -EFAULT;



	frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);

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

	uc_flags = frame_uc_flags(regs);



	if (!user_access_begin(frame, sizeof(*frame)))
@@ -572,7 +585,7 @@ static int x32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) 
	if (!(ksig->ka.sa.sa_flags & SA_RESTORER))

		return -EFAULT;



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

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



	uc_flags = frame_uc_flags(regs);
@@ -742,23 +755,6 @@ unsigned long get_sigframe_size(void) 
	return max_frame_size;

}



static inline int is_ia32_compat_frame(struct ksignal *ksig)

{

	return IS_ENABLED(CONFIG_IA32_EMULATION) &&

		ksig->ka.sa.sa_flags & SA_IA32_ABI;

}



static inline int is_ia32_frame(struct ksignal *ksig)

{

	return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame(ksig);

}



static inline int is_x32_frame(struct ksignal *ksig)

{

	return IS_ENABLED(CONFIG_X86_X32_ABI) &&

		ksig->ka.sa.sa_flags & SA_X32_ABI;

}



static int

setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)

{