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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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