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    Subject[RFC v2 -tip 3/3] x86: ia32_signal: use {get|put}_user_try and catch
    From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>

    Impact: use new framework

    Use {get|put}_user_try, catch, and _ex in arch/x86/ia32/ia32_signal.c.

    Note: this patch contains "WARNING: line over 80 characters", because when
    introducing new block I insert an indent to avoid mistakes by edit.

    Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
    ---
    arch/x86/ia32/ia32_signal.c | 365 +++++++++++++++++++++++--------------------
    1 files changed, 195 insertions(+), 170 deletions(-)

    diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
    index 9dabd00..dd77ac0 100644
    --- a/arch/x86/ia32/ia32_signal.c
    +++ b/arch/x86/ia32/ia32_signal.c
    @@ -46,78 +46,83 @@ void signal_fault(struct pt_regs *regs, void __user *frame, char *where);

    int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
    {
    - int err;
    + int err = 0;

    if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t)))
    return -EFAULT;

    - /* If you change siginfo_t structure, please make sure that
    - this code is fixed accordingly.
    - It should never copy any pad contained in the structure
    - to avoid security leaks, but must copy the generic
    - 3 ints plus the relevant union member. */
    - err = __put_user(from->si_signo, &to->si_signo);
    - err |= __put_user(from->si_errno, &to->si_errno);
    - err |= __put_user((short)from->si_code, &to->si_code);
    -
    - if (from->si_code < 0) {
    - err |= __put_user(from->si_pid, &to->si_pid);
    - err |= __put_user(from->si_uid, &to->si_uid);
    - err |= __put_user(ptr_to_compat(from->si_ptr), &to->si_ptr);
    - } else {
    - /*
    - * First 32bits of unions are always present:
    - * si_pid === si_band === si_tid === si_addr(LS half)
    - */
    - err |= __put_user(from->_sifields._pad[0],
    - &to->_sifields._pad[0]);
    - switch (from->si_code >> 16) {
    - case __SI_FAULT >> 16:
    - break;
    - case __SI_CHLD >> 16:
    - err |= __put_user(from->si_utime, &to->si_utime);
    - err |= __put_user(from->si_stime, &to->si_stime);
    - err |= __put_user(from->si_status, &to->si_status);
    - /* FALL THROUGH */
    - default:
    - case __SI_KILL >> 16:
    - err |= __put_user(from->si_uid, &to->si_uid);
    - break;
    - case __SI_POLL >> 16:
    - err |= __put_user(from->si_fd, &to->si_fd);
    - break;
    - case __SI_TIMER >> 16:
    - err |= __put_user(from->si_overrun, &to->si_overrun);
    - err |= __put_user(ptr_to_compat(from->si_ptr),
    - &to->si_ptr);
    - break;
    - /* This is not generated by the kernel as of now. */
    - case __SI_RT >> 16:
    - case __SI_MESGQ >> 16:
    - err |= __put_user(from->si_uid, &to->si_uid);
    - err |= __put_user(from->si_int, &to->si_int);
    - break;
    + put_user_try {
    + /* If you change siginfo_t structure, please make sure that
    + this code is fixed accordingly.
    + It should never copy any pad contained in the structure
    + to avoid security leaks, but must copy the generic
    + 3 ints plus the relevant union member. */
    + put_user_ex(from->si_signo, &to->si_signo);
    + put_user_ex(from->si_errno, &to->si_errno);
    + put_user_ex((short)from->si_code, &to->si_code);
    +
    + if (from->si_code < 0) {
    + put_user_ex(from->si_pid, &to->si_pid);
    + put_user_ex(from->si_uid, &to->si_uid);
    + put_user_ex(ptr_to_compat(from->si_ptr), &to->si_ptr);
    + } else {
    + /*
    + * First 32bits of unions are always present:
    + * si_pid === si_band === si_tid === si_addr(LS half)
    + */
    + put_user_ex(from->_sifields._pad[0],
    + &to->_sifields._pad[0]);
    + switch (from->si_code >> 16) {
    + case __SI_FAULT >> 16:
    + break;
    + case __SI_CHLD >> 16:
    + put_user_ex(from->si_utime, &to->si_utime);
    + put_user_ex(from->si_stime, &to->si_stime);
    + put_user_ex(from->si_status, &to->si_status);
    + /* FALL THROUGH */
    + default:
    + case __SI_KILL >> 16:
    + put_user_ex(from->si_uid, &to->si_uid);
    + break;
    + case __SI_POLL >> 16:
    + put_user_ex(from->si_fd, &to->si_fd);
    + break;
    + case __SI_TIMER >> 16:
    + put_user_ex(from->si_overrun, &to->si_overrun);
    + put_user_ex(ptr_to_compat(from->si_ptr),
    + &to->si_ptr);
    + break;
    + /* This is not generated by the kernel as of now. */
    + case __SI_RT >> 16:
    + case __SI_MESGQ >> 16:
    + put_user_ex(from->si_uid, &to->si_uid);
    + put_user_ex(from->si_int, &to->si_int);
    + break;
    + }
    }
    - }
    + } put_user_catch(err);
    +
    return err;
    }

    int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
    {
    - int err;
    + int err = 0;
    u32 ptr32;

    if (!access_ok(VERIFY_READ, from, sizeof(compat_siginfo_t)))
    return -EFAULT;

    - err = __get_user(to->si_signo, &from->si_signo);
    - err |= __get_user(to->si_errno, &from->si_errno);
    - err |= __get_user(to->si_code, &from->si_code);
    + get_user_try {
    + get_user_ex(to->si_signo, &from->si_signo);
    + get_user_ex(to->si_errno, &from->si_errno);
    + get_user_ex(to->si_code, &from->si_code);

    - err |= __get_user(to->si_pid, &from->si_pid);
    - err |= __get_user(to->si_uid, &from->si_uid);
    - err |= __get_user(ptr32, &from->si_ptr);
    - to->si_ptr = compat_ptr(ptr32);
    + get_user_ex(to->si_pid, &from->si_pid);
    + get_user_ex(to->si_uid, &from->si_uid);
    + get_user_ex(ptr32, &from->si_ptr);
    + to->si_ptr = compat_ptr(ptr32);
    + } get_user_catch(err);

    return err;
    }
    @@ -142,17 +147,23 @@ asmlinkage long sys32_sigaltstack(const stack_ia32_t __user *uss_ptr,
    struct pt_regs *regs)
    {
    stack_t uss, uoss;
    - int ret;
    + int ret, err = 0;
    mm_segment_t seg;

    if (uss_ptr) {
    u32 ptr;

    memset(&uss, 0, sizeof(stack_t));
    - if (!access_ok(VERIFY_READ, uss_ptr, sizeof(stack_ia32_t)) ||
    - __get_user(ptr, &uss_ptr->ss_sp) ||
    - __get_user(uss.ss_flags, &uss_ptr->ss_flags) ||
    - __get_user(uss.ss_size, &uss_ptr->ss_size))
    + if (!access_ok(VERIFY_READ, uss_ptr, sizeof(stack_ia32_t)))
    + return -EFAULT;
    +
    + get_user_try {
    + get_user_ex(ptr, &uss_ptr->ss_sp);
    + get_user_ex(uss.ss_flags, &uss_ptr->ss_flags);
    + get_user_ex(uss.ss_size, &uss_ptr->ss_size);
    + } get_user_catch(err);
    +
    + if (err)
    return -EFAULT;
    uss.ss_sp = compat_ptr(ptr);
    }
    @@ -161,10 +172,16 @@ asmlinkage long sys32_sigaltstack(const stack_ia32_t __user *uss_ptr,
    ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss, regs->sp);
    set_fs(seg);
    if (ret >= 0 && uoss_ptr) {
    - if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(stack_ia32_t)) ||
    - __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) ||
    - __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) ||
    - __put_user(uoss.ss_size, &uoss_ptr->ss_size))
    + if (!access_ok(VERIFY_WRITE, uoss_ptr, sizeof(stack_ia32_t)))
    + return -EFAULT;
    +
    + put_user_try {
    + put_user_ex(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp);
    + put_user_ex(uoss.ss_flags, &uoss_ptr->ss_flags);
    + put_user_ex(uoss.ss_size, &uoss_ptr->ss_size);
    + } put_user_catch(err);
    +
    + if (err)
    ret = -EFAULT;
    }
    return ret;
    @@ -174,18 +191,18 @@ asmlinkage long sys32_sigaltstack(const stack_ia32_t __user *uss_ptr,
    * Do a signal return; undo the signal stack.
    */
    #define COPY(x) { \
    - err |= __get_user(regs->x, &sc->x); \
    + get_user_ex(regs->x, &sc->x); \
    }

    #define COPY_SEG_CPL3(seg) { \
    unsigned short tmp; \
    - err |= __get_user(tmp, &sc->seg); \
    + get_user_ex(tmp, &sc->seg); \
    regs->seg = tmp | 3; \
    }

    #define RELOAD_SEG(seg) { \
    unsigned int cur, pre; \
    - err |= __get_user(pre, &sc->seg); \
    + get_user_ex(pre, &sc->seg); \
    savesegment(seg, cur); \
    pre |= 3; \
    if (pre != cur) \
    @@ -209,39 +226,42 @@ static int ia32_restore_sigcontext(struct pt_regs *regs,
    sc, sc->err, sc->ip, sc->cs, sc->flags);
    #endif

    - /*
    - * Reload fs and gs if they have changed in the signal
    - * handler. This does not handle long fs/gs base changes in
    - * the handler, but does not clobber them at least in the
    - * normal case.
    - */
    - err |= __get_user(gs, &sc->gs);
    - gs |= 3;
    - savesegment(gs, oldgs);
    - if (gs != oldgs)
    - load_gs_index(gs);
    -
    - RELOAD_SEG(fs);
    - RELOAD_SEG(ds);
    - RELOAD_SEG(es);
    -
    - COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
    - COPY(dx); COPY(cx); COPY(ip);
    - /* Don't touch extended registers */
    -
    - COPY_SEG_CPL3(cs);
    - COPY_SEG_CPL3(ss);
    -
    - err |= __get_user(tmpflags, &sc->flags);
    - regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
    - /* disable syscall checks */
    - regs->orig_ax = -1;
    -
    - err |= __get_user(tmp, &sc->fpstate);
    - buf = compat_ptr(tmp);
    - err |= restore_i387_xstate_ia32(buf);
    -
    - err |= __get_user(*pax, &sc->ax);
    + get_user_try {
    + /*
    + * Reload fs and gs if they have changed in the signal
    + * handler. This does not handle long fs/gs base changes in
    + * the handler, but does not clobber them at least in the
    + * normal case.
    + */
    + get_user_ex(gs, &sc->gs);
    + gs |= 3;
    + savesegment(gs, oldgs);
    + if (gs != oldgs)
    + load_gs_index(gs);
    +
    + RELOAD_SEG(fs);
    + RELOAD_SEG(ds);
    + RELOAD_SEG(es);
    +
    + COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
    + COPY(dx); COPY(cx); COPY(ip);
    + /* Don't touch extended registers */
    +
    + COPY_SEG_CPL3(cs);
    + COPY_SEG_CPL3(ss);
    +
    + get_user_ex(tmpflags, &sc->flags);
    + regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
    + /* disable syscall checks */
    + regs->orig_ax = -1;
    +
    + get_user_ex(tmp, &sc->fpstate);
    + buf = compat_ptr(tmp);
    + err |= restore_i387_xstate_ia32(buf);
    +
    + get_user_ex(*pax, &sc->ax);
    + } get_user_catch(err);
    +
    return err;
    }

    @@ -319,36 +339,38 @@ static int ia32_setup_sigcontext(struct sigcontext_ia32 __user *sc,
    {
    int tmp, err = 0;

    - savesegment(gs, tmp);
    - err |= __put_user(tmp, (unsigned int __user *)&sc->gs);
    - savesegment(fs, tmp);
    - err |= __put_user(tmp, (unsigned int __user *)&sc->fs);
    - savesegment(ds, tmp);
    - err |= __put_user(tmp, (unsigned int __user *)&sc->ds);
    - savesegment(es, tmp);
    - err |= __put_user(tmp, (unsigned int __user *)&sc->es);
    -
    - err |= __put_user(regs->di, &sc->di);
    - err |= __put_user(regs->si, &sc->si);
    - err |= __put_user(regs->bp, &sc->bp);
    - err |= __put_user(regs->sp, &sc->sp);
    - err |= __put_user(regs->bx, &sc->bx);
    - err |= __put_user(regs->dx, &sc->dx);
    - err |= __put_user(regs->cx, &sc->cx);
    - err |= __put_user(regs->ax, &sc->ax);
    - err |= __put_user(current->thread.trap_no, &sc->trapno);
    - err |= __put_user(current->thread.error_code, &sc->err);
    - err |= __put_user(regs->ip, &sc->ip);
    - err |= __put_user(regs->cs, (unsigned int __user *)&sc->cs);
    - err |= __put_user(regs->flags, &sc->flags);
    - err |= __put_user(regs->sp, &sc->sp_at_signal);
    - err |= __put_user(regs->ss, (unsigned int __user *)&sc->ss);
    -
    - err |= __put_user(ptr_to_compat(fpstate), &sc->fpstate);
    -
    - /* non-iBCS2 extensions.. */
    - err |= __put_user(mask, &sc->oldmask);
    - err |= __put_user(current->thread.cr2, &sc->cr2);
    + put_user_try {
    + savesegment(gs, tmp);
    + put_user_ex(tmp, (unsigned int __user *)&sc->gs);
    + savesegment(fs, tmp);
    + put_user_ex(tmp, (unsigned int __user *)&sc->fs);
    + savesegment(ds, tmp);
    + put_user_ex(tmp, (unsigned int __user *)&sc->ds);
    + savesegment(es, tmp);
    + put_user_ex(tmp, (unsigned int __user *)&sc->es);
    +
    + 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);
    + put_user_ex(current->thread.trap_no, &sc->trapno);
    + put_user_ex(current->thread.error_code, &sc->err);
    + put_user_ex(regs->ip, &sc->ip);
    + 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);
    +
    + put_user_ex(ptr_to_compat(fpstate), &sc->fpstate);
    +
    + /* non-iBCS2 extensions.. */
    + put_user_ex(mask, &sc->oldmask);
    + put_user_ex(current->thread.cr2, &sc->cr2);
    + } put_user_catch(err);

    return err;
    }
    @@ -437,13 +459,17 @@ int ia32_setup_frame(int sig, struct k_sigaction *ka,
    else
    restorer = &frame->retcode;
    }
    - err |= __put_user(ptr_to_compat(restorer), &frame->pretcode);

    - /*
    - * These are actually not used anymore, but left because some
    - * gdb versions depend on them as a marker.
    - */
    - err |= __put_user(*((u64 *)&code), (u64 *)frame->retcode);
    + put_user_try {
    + put_user_ex(ptr_to_compat(restorer), &frame->pretcode);
    +
    + /*
    + * These are actually not used anymore, but left because some
    + * gdb versions depend on them as a marker.
    + */
    + put_user_ex(*((u64 *)&code), (u64 *)frame->retcode);
    + } put_user_catch(err);
    +
    if (err)
    return -EFAULT;

    @@ -496,41 +522,40 @@ int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
    if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
    return -EFAULT;

    - err |= __put_user(sig, &frame->sig);
    - err |= __put_user(ptr_to_compat(&frame->info), &frame->pinfo);
    - err |= __put_user(ptr_to_compat(&frame->uc), &frame->puc);
    - err |= copy_siginfo_to_user32(&frame->info, info);
    - if (err)
    - return -EFAULT;
    + put_user_try {
    + put_user_ex(sig, &frame->sig);
    + put_user_ex(ptr_to_compat(&frame->info), &frame->pinfo);
    + put_user_ex(ptr_to_compat(&frame->uc), &frame->puc);
    + err |= copy_siginfo_to_user32(&frame->info, info);

    - /* Create the ucontext. */
    - if (cpu_has_xsave)
    - err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
    - else
    - err |= __put_user(0, &frame->uc.uc_flags);
    - err |= __put_user(0, &frame->uc.uc_link);
    - err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
    - err |= __put_user(sas_ss_flags(regs->sp),
    - &frame->uc.uc_stack.ss_flags);
    - err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
    - err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
    - regs, set->sig[0]);
    - err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
    - if (err)
    - return -EFAULT;
    + /* Create the ucontext. */
    + if (cpu_has_xsave)
    + put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
    + else
    + put_user_ex(0, &frame->uc.uc_flags);
    + put_user_ex(0, &frame->uc.uc_link);
    + put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
    + put_user_ex(sas_ss_flags(regs->sp),
    + &frame->uc.uc_stack.ss_flags);
    + put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
    + err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
    + regs, set->sig[0]);
    + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
    +
    + if (ka->sa.sa_flags & SA_RESTORER)
    + restorer = ka->sa.sa_restorer;
    + else
    + restorer = VDSO32_SYMBOL(current->mm->context.vdso,
    + rt_sigreturn);
    + put_user_ex(ptr_to_compat(restorer), &frame->pretcode);
    +
    + /*
    + * Not actually used anymore, but left because some gdb
    + * versions need it.
    + */
    + put_user_ex(*((u64 *)&code), (u64 *)frame->retcode);
    + } put_user_catch(err);

    - if (ka->sa.sa_flags & SA_RESTORER)
    - restorer = ka->sa.sa_restorer;
    - else
    - restorer = VDSO32_SYMBOL(current->mm->context.vdso,
    - rt_sigreturn);
    - err |= __put_user(ptr_to_compat(restorer), &frame->pretcode);
    -
    - /*
    - * Not actually used anymore, but left because some gdb
    - * versions need it.
    - */
    - err |= __put_user(*((u64 *)&code), (u64 *)frame->retcode);
    if (err)
    return -EFAULT;

    --
    1.6.0.4


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