[PATCH] generic copy_siginfo_to_user cleanup

Stephen Rothwell (sfr@canb.auug.org.au)
Thu, 30 May 2002 15:47:54 +1000


Hi Linus,

This patch does two things:
- makes copy_siginfo_to_user always return either 0 or
-EFAULT (as all its callers either expect or don't
care about).
- explicitly copies the correct union of the siginfo structure.

Compiles on i386. Obviously correct :-)

-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au
http://www.canb.auug.org.au/~sfr/

diff -ruN 2.5.19/kernel/signal.c 2.5.19-si.2/kernel/signal.c --- 2.5.19/kernel/signal.c Thu May 30 09:44:39 2002 +++ 2.5.19-si.2/kernel/signal.c Thu May 30 15:24:47 2002 @@ -1043,37 +1043,58 @@ int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from) { + int err; + if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) return -EFAULT; if (from->si_code < 0) - return __copy_to_user(to, from, sizeof(siginfo_t)); - else { - int err; - - /* If you change siginfo_t structure, please be sure - 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); - /* First 32bits of unions are always present. */ + return __copy_to_user(to, from, sizeof(siginfo_t)) + ? -EFAULT : 0; + /* + * If you change siginfo_t structure, please be sure + * 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); + switch (from->si_code && __SI_MASK) { + case __SI_KILL: + err |= __put_user(from->si_pid, &to->si_pid); + err |= __put_user(from->si_uid, &to->si_uid); + break; + case __SI_TIMER: + err |= __put_user(from->si_timer1, &to->si_timer1); + err |= __put_user(from->si_timer2, &to->si_timer2); + break; + case __SI_POLL: + err |= __put_user(from->si_band, &to->si_band); + err |= __put_user(from->si_fd, &to->si_fd); + break; + case __SI_FAULT: + err |= __put_user(from->si_addr, &to->si_addr); + break; + case __SI_CHLD: + err |= __put_user(from->si_pid, &to->si_pid); + err |= __put_user(from->si_uid, &to->si_uid); + err |= __put_user(from->si_status, &to->si_status); + err |= __put_user(from->si_utime, &to->si_utime); + err |= __put_user(from->si_stime, &to->si_stime); + break; + case __SI_RT: /* This is not generated by the kernel as of now. */ + err |= __put_user(from->si_pid, &to->si_pid); + err |= __put_user(from->si_uid, &to->si_uid); + err |= __put_user(from->si_int, &to->si_int); + err |= __put_user(from->si_ptr, &to->si_ptr); + break; + default: /* this is just in case for now ... */ err |= __put_user(from->si_pid, &to->si_pid); - 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); - default: - err |= __put_user(from->si_uid, &to->si_uid); - break; - /* case __SI_RT: This is not generated by the kernel as of now. */ - } - return err; + err |= __put_user(from->si_uid, &to->si_uid); + break; } + return err; } #endif - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/