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Subject[RFC][PATCH v2 10/22] x86: switch setup_sigcontext() to unsafe_put_user()
Date
From: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
arch/x86/include/asm/sighandling.h | 3 --
arch/x86/kernel/signal.c | 88 +++++++++++++++++++-------------------
2 files changed, 45 insertions(+), 46 deletions(-)

diff --git a/arch/x86/include/asm/sighandling.h b/arch/x86/include/asm/sighandling.h
index 2fcbd6f33ef7..35e0b579ffcb 100644
--- a/arch/x86/include/asm/sighandling.h
+++ b/arch/x86/include/asm/sighandling.h
@@ -14,9 +14,6 @@
X86_EFLAGS_CF | X86_EFLAGS_RF)

void signal_fault(struct pt_regs *regs, void __user *frame, char *where);
-int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
- struct pt_regs *regs, unsigned long mask);
-

#ifdef CONFIG_X86_X32_ABI
asmlinkage long sys32_x32_rt_sigreturn(void);
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 83563e98f0be..3b4ca484cfc2 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -140,63 +140,65 @@ static int restore_sigcontext(struct pt_regs *regs,
IS_ENABLED(CONFIG_X86_32));
}

-int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
+static int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
struct pt_regs *regs, unsigned long mask)
{
- int err = 0;
-
- put_user_try {
+ if (!user_access_begin(sc, sizeof(struct sigcontext)))
+ return -EFAULT;

#ifdef CONFIG_X86_32
- put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
- put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
- put_user_ex(regs->es, (unsigned int __user *)&sc->es);
- put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
+ unsafe_put_user(get_user_gs(regs),
+ (unsigned int __user *)&sc->gs, Efault);
+ unsafe_put_user(regs->fs, (unsigned int __user *)&sc->fs, Efault);
+ unsafe_put_user(regs->es, (unsigned int __user *)&sc->es, Efault);
+ unsafe_put_user(regs->ds, (unsigned int __user *)&sc->ds, Efault);
#endif /* CONFIG_X86_32 */

- put_user_ex(regs->di, &sc->di);
- put_user_ex(regs->si, &sc->si);
- put_user_ex(regs->bp, &sc->bp);
- put_user_ex(regs->sp, &sc->sp);
- put_user_ex(regs->bx, &sc->bx);
- put_user_ex(regs->dx, &sc->dx);
- put_user_ex(regs->cx, &sc->cx);
- put_user_ex(regs->ax, &sc->ax);
+ unsafe_put_user(regs->di, &sc->di, Efault);
+ unsafe_put_user(regs->si, &sc->si, Efault);
+ unsafe_put_user(regs->bp, &sc->bp, Efault);
+ unsafe_put_user(regs->sp, &sc->sp, Efault);
+ unsafe_put_user(regs->bx, &sc->bx, Efault);
+ unsafe_put_user(regs->dx, &sc->dx, Efault);
+ unsafe_put_user(regs->cx, &sc->cx, Efault);
+ unsafe_put_user(regs->ax, &sc->ax, Efault);
#ifdef CONFIG_X86_64
- put_user_ex(regs->r8, &sc->r8);
- put_user_ex(regs->r9, &sc->r9);
- put_user_ex(regs->r10, &sc->r10);
- put_user_ex(regs->r11, &sc->r11);
- put_user_ex(regs->r12, &sc->r12);
- put_user_ex(regs->r13, &sc->r13);
- put_user_ex(regs->r14, &sc->r14);
- put_user_ex(regs->r15, &sc->r15);
+ unsafe_put_user(regs->r8, &sc->r8, Efault);
+ unsafe_put_user(regs->r9, &sc->r9, Efault);
+ unsafe_put_user(regs->r10, &sc->r10, Efault);
+ unsafe_put_user(regs->r11, &sc->r11, Efault);
+ unsafe_put_user(regs->r12, &sc->r12, Efault);
+ unsafe_put_user(regs->r13, &sc->r13, Efault);
+ unsafe_put_user(regs->r14, &sc->r14, Efault);
+ unsafe_put_user(regs->r15, &sc->r15, Efault);
#endif /* CONFIG_X86_64 */

- put_user_ex(current->thread.trap_nr, &sc->trapno);
- put_user_ex(current->thread.error_code, &sc->err);
- put_user_ex(regs->ip, &sc->ip);
+ unsafe_put_user(current->thread.trap_nr, &sc->trapno, Efault);
+ unsafe_put_user(current->thread.error_code, &sc->err, Efault);
+ unsafe_put_user(regs->ip, &sc->ip, Efault);
#ifdef CONFIG_X86_32
- put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
- put_user_ex(regs->flags, &sc->flags);
- put_user_ex(regs->sp, &sc->sp_at_signal);
- put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
+ unsafe_put_user(regs->cs, (unsigned int __user *)&sc->cs, Efault);
+ unsafe_put_user(regs->flags, &sc->flags, Efault);
+ unsafe_put_user(regs->sp, &sc->sp_at_signal, Efault);
+ unsafe_put_user(regs->ss, (unsigned int __user *)&sc->ss, Efault);
#else /* !CONFIG_X86_32 */
- put_user_ex(regs->flags, &sc->flags);
- put_user_ex(regs->cs, &sc->cs);
- put_user_ex(0, &sc->gs);
- put_user_ex(0, &sc->fs);
- put_user_ex(regs->ss, &sc->ss);
+ unsafe_put_user(regs->flags, &sc->flags, Efault);
+ unsafe_put_user(regs->cs, &sc->cs, Efault);
+ unsafe_put_user(0, &sc->gs, Efault);
+ unsafe_put_user(0, &sc->fs, Efault);
+ unsafe_put_user(regs->ss, &sc->ss, Efault);
#endif /* CONFIG_X86_32 */

- put_user_ex(fpstate, (unsigned long __user *)&sc->fpstate);
+ unsafe_put_user(fpstate, (unsigned long __user *)&sc->fpstate, Efault);

- /* non-iBCS2 extensions.. */
- put_user_ex(mask, &sc->oldmask);
- put_user_ex(current->thread.cr2, &sc->cr2);
- } put_user_catch(err);
-
- return err;
+ /* 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;
}

/*
--
2.11.0
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