Re: [RFC v2 -tip 3/3] x86: ia32_signal: use {get|put}_user_try and catch

Cyrill Gorcunov
2009-01-24T07:36:51Z

[Hiroshi Shimamoto - Fri, Jan 23, 2009 at 03:50:38PM -0800]
| 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);
|
...
| + 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:

Hi Hiroshi,

may I ask why we use default here?

| + 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;
| }
|
...

- Cyrill -