Commit 9504db3e authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/signal32: Switch handle_rt_signal32() to user_access_begin() logic 



On the same way as handle_signal32(), replace all user
accesses with equivalent unsafe_ versions, and move the
trampoline code icache flush outside the user access block.

Functions that have no unsafe_ equivalent also remains outside
the access block.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/2974314226256f958e2984912b48883ef1754185.1597770847.git.christophe.leroy@csgroup.eu
parent ad65f490

arch/powerpc/kernel/signal_32.c

+34 −21
Original line number Diff line number Diff line
@@ -58,8 +58,6 @@ 
#define mcontext	mcontext32

#define ucontext	ucontext32



#define __save_altstack __compat_save_altstack



/*

 * Userspace code may pass a ucontext which doesn't include VSX added

 * at the end.  We need to check for this case.
@@ -745,16 +743,28 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset, 
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

	tm_mctx = &frame->uc_transact.uc_mcontext;

#endif

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

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

		goto badframe;



	/* Put the siginfo & fill in most of the ucontext */

	if (copy_siginfo_to_user(&frame->info, &ksig->info) ||

	    __put_user(0, &frame->uc.uc_flags) ||

	    __save_altstack(&frame->uc.uc_stack, regs->gpr[1]) ||

	    __put_user(to_user_ptr(&frame->uc.uc_mcontext), &frame->uc.uc_regs) ||

	    put_sigset_t(&frame->uc.uc_sigmask, oldset))

		goto badframe;

	unsafe_put_user(0, &frame->uc.uc_flags, failed);

#ifdef CONFIG_PPC64

	unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->gpr[1], failed);

#else

	unsafe_save_altstack(&frame->uc.uc_stack, regs->gpr[1], failed);

#endif

	unsafe_put_user(to_user_ptr(&frame->uc.uc_mcontext), &frame->uc.uc_regs, failed);



	if (MSR_TM_ACTIVE(msr)) {

#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

		unsafe_put_user((unsigned long)&frame->uc_transact,

				&frame->uc.uc_link, failed);

		unsafe_put_user((unsigned long)tm_mctx,

				&frame->uc_transact.uc_regs, failed);

#endif

	} else {

		unsafe_put_user(0, &frame->uc.uc_link, failed);

	}



	/* Save user registers on the stack */

	if (vdso32_rt_sigtramp && tsk->mm->context.vdso_base) {
@@ -762,28 +772,28 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset, 
	} else {

		tramp = (unsigned long)mctx->mc_pad;

		/* Set up the sigreturn trampoline: li r0,sigret; sc */

		if (__put_user(PPC_INST_ADDI + __NR_sigreturn, &mctx->mc_pad[0]))

		unsafe_put_user(PPC_INST_ADDI + __NR_rt_sigreturn, &mctx->mc_pad[0],

				failed);

		unsafe_put_user(PPC_INST_SC, &mctx->mc_pad[1], failed);

	}

	user_write_access_end();



	if (put_sigset_t(&frame->uc.uc_sigmask, oldset))

		goto badframe;

		if (__put_user(PPC_INST_SC, &mctx->mc_pad[1]))

	if (copy_siginfo_to_user(&frame->info, &ksig->info))

		goto badframe;



	if (tramp == (unsigned long)mctx->mc_pad)

		flush_icache_range(tramp, tramp + 2 * sizeof(unsigned long));

	}



#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

	if (MSR_TM_ACTIVE(msr)) {

		if (__put_user((unsigned long)&frame->uc_transact,

			       &frame->uc.uc_link) ||

		    __put_user((unsigned long)tm_mctx,

			       &frame->uc_transact.uc_regs))

			goto badframe;

		if (save_tm_user_regs(regs, mctx, tm_mctx, msr))

			goto badframe;

	}

	else

#endif

	{

		if (__put_user(0, &frame->uc.uc_link))

			goto badframe;

		if (save_user_regs(regs, mctx, tm_mctx, 1))

			goto badframe;

	}
@@ -810,6 +820,9 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset, 
	regs->msr |= (MSR_KERNEL & MSR_LE);

	return 0;



failed:

	user_write_access_end();



badframe:

	signal_fault(tsk, regs, "handle_rt_signal32", frame);