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From: "Eric W. Biederman" <ebiederm@xmission.com>
To: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
	"Eric W. Biederman" <ebiederm@xmission.com>
Subject: [REVIEW][PATCH 07/17] signal: Reduce copy_siginfo_to_user to just copy_to_user
Date: Thu, 19 Apr 2018 20:03:58 -0500	[thread overview]
Message-ID: <20180420010408.24438-7-ebiederm@xmission.com> (raw)
In-Reply-To: <878t9ilmhv.fsf@xmission.com>

Now that every instance of struct siginfo is now initialized it is no
longer necessary to copy struct siginfo piece by piece to userspace
but instead the entire structure can be copied.

As well as making the code simpler and more efficient this means that
copy_sinfo_to_user no longer cares which union member of struct
siginfo is in use.

In practice this means that all 32bit architectures that define
FPE_FIXME will handle properly send SI_USER when kill(SIGFPE) is sent.
While still performing their historic architectural brokenness when 0
is used a floating pointer signal.  This matches the current behavior
of 64bit architectures that define FPE_FIXME who get lucky and an
overloaded SI_USER has continuted to work through copy_siginfo_to_user
because the 8 byte si_addr occupies the same bytes in struct siginfo
as the 4 byte si_pid and the 4 byte si_uid.

Problematic architectures still need to fix their ABI so that signalfd
and 32bit compat code will work properly.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 kernel/signal.c | 84 ++-------------------------------------------------------
 1 file changed, 2 insertions(+), 82 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index d4ccea599692..d56f4d496c89 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2850,89 +2850,9 @@ enum siginfo_layout siginfo_layout(int sig, int si_code)
 
 int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
 {
-	int err;
-
-	if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
+	if (copy_to_user(to, from , sizeof(struct siginfo)))
 		return -EFAULT;
-	if (from->si_code < 0)
-		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.
-	 * Please remember to update the signalfd_copyinfo() function
-	 * inside fs/signalfd.c too, in case siginfo_t changes.
-	 * 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(from->si_code, &to->si_code);
-	switch (siginfo_layout(from->si_signo, from->si_code)) {
-	case SIL_KILL:
-		err |= __put_user(from->si_pid, &to->si_pid);
-		err |= __put_user(from->si_uid, &to->si_uid);
-		break;
-	case SIL_TIMER:
-		/* Unreached SI_TIMER is negative */
-		break;
-	case SIL_POLL:
-		err |= __put_user(from->si_band, &to->si_band);
-		err |= __put_user(from->si_fd, &to->si_fd);
-		break;
-	case SIL_FAULT:
-		err |= __put_user(from->si_addr, &to->si_addr);
-#ifdef __ARCH_SI_TRAPNO
-		err |= __put_user(from->si_trapno, &to->si_trapno);
-#endif
-#ifdef __ia64__
-		err |= __put_user(from->si_imm, &to->si_imm);
-		err |= __put_user(from->si_flags, &to->si_flags);
-		err |= __put_user(from->si_isr, &to->si_isr);
-#endif
-		/*
-		 * Other callers might not initialize the si_lsb field,
-		 * so check explicitly for the right codes here.
-		 */
-#ifdef BUS_MCEERR_AR
-		if (from->si_signo == SIGBUS && from->si_code == BUS_MCEERR_AR)
-			err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
-#endif
-#ifdef BUS_MCEERR_AO
-		if (from->si_signo == SIGBUS && from->si_code == BUS_MCEERR_AO)
-			err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
-#endif
-#ifdef SEGV_BNDERR
-		if (from->si_signo == SIGSEGV && from->si_code == SEGV_BNDERR) {
-			err |= __put_user(from->si_lower, &to->si_lower);
-			err |= __put_user(from->si_upper, &to->si_upper);
-		}
-#endif
-#ifdef SEGV_PKUERR
-		if (from->si_signo == SIGSEGV && from->si_code == SEGV_PKUERR)
-			err |= __put_user(from->si_pkey, &to->si_pkey);
-#endif
-		break;
-	case SIL_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 SIL_RT:
-		err |= __put_user(from->si_pid, &to->si_pid);
-		err |= __put_user(from->si_uid, &to->si_uid);
-		err |= __put_user(from->si_ptr, &to->si_ptr);
-		break;
-	case SIL_SYS:
-		err |= __put_user(from->si_call_addr, &to->si_call_addr);
-		err |= __put_user(from->si_syscall, &to->si_syscall);
-		err |= __put_user(from->si_arch, &to->si_arch);
-		break;
-	}
-	return err;
+	return 0;
 }
 
 #ifdef CONFIG_COMPAT
-- 
2.14.1


  parent reply	other threads:[~2018-04-20  1:07 UTC|newest]

Thread overview: 77+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-20  1:01 [REVIEW][PATCH 00/17] siginfo bugfixes and cleanups Eric W. Biederman
2018-04-20  1:03 ` [REVIEW][PATCH 01/17] signal/alpha: Document a conflict with SI_USER for SIGFPE Eric W. Biederman
2018-04-20  1:03 ` [REVIEW][PATCH 02/17] sparc: fix compat siginfo ABI regression Eric W. Biederman
2018-04-20  1:03 ` [REVIEW][PATCH 03/17] signal/sh: Use force_sig_fault in hw_breakpoint_handler Eric W. Biederman
2018-04-20  1:03 ` [REVIEW][PATCH 04/17] signal/nds32: Use force_sig in unhandled_interruption and unhandled_exceptions Eric W. Biederman
2018-04-25 12:14   ` Vincent Chen
2018-04-20  1:03 ` [REVIEW][PATCH 05/17] signal/nds32: Use force_sig(SIGILL) in do_revisn Eric W. Biederman
2018-04-25 12:10   ` Vincent Chen
2018-04-25 16:13     ` [PATCH] signal/nds32: More information in do_revinsn Eric W. Biederman
2018-04-26  3:02       ` Vincent Chen
2018-04-20  1:03 ` [REVIEW][PATCH 06/17] signal: Ensure every siginfo we send has all bits initialized Eric W. Biederman
2018-04-20  1:03 ` Eric W. Biederman [this message]
2018-04-20  1:03 ` [REVIEW][PATCH 08/17] signal: Stop special casing TRAP_FIXME and FPE_FIXME in siginfo_layout Eric W. Biederman
2018-04-20  1:04 ` [REVIEW][PATCH 09/17] signal: Remove SEGV_BNDERR ifdefs Eric W. Biederman
2018-04-20  1:04 ` [REVIEW][PATCH 10/17] signal: Remove ifdefs for BUS_MCEERR_AR and BUS_MCEERR_AO Eric W. Biederman
2018-04-20  1:04 ` [REVIEW][PATCH 11/17] signal/alpha: Replace FPE_FIXME with FPE_FLTUNK Eric W. Biederman
2018-04-20  1:04 ` [REVIEW][PATCH 12/17] signal/ia64: " Eric W. Biederman
2018-04-20  1:04 ` [REVIEW][PATCH 13/17] signal/powerpc: " Eric W. Biederman
2018-04-20  1:04 ` [REVIEW][PATCH 14/17] signal/unicore32: Use FPE_FLTUNK instead of 0 in ucf64_raise_sigfpe Eric W. Biederman
2018-04-20  1:04 ` [REVIEW][PATCH 15/17] signal: Add TRAP_UNK si_code for undiagnosted trap exceptions Eric W. Biederman
2018-04-20  1:04 ` [REVIEW][PATCH 16/17] signal/alpha: Replace TRAP_FIXME with TRAP_UNK Eric W. Biederman
2018-04-20  1:04 ` [REVIEW][PATCH 17/17] signal/powerpc: " Eric W. Biederman
2018-04-20 14:35 ` [REVIEW][PATCH 00/22] Simplifying siginfo users Eric W. Biederman
2018-04-20 14:37   ` [REVIEW][PATCH 01/22] signal/alpha: Use send_sig_fault where appropriate Eric W. Biederman
2018-04-20 14:37   ` [REVIEW][PATCH 02/22] signal/alpha: Use force_sig_fault " Eric W. Biederman
2018-04-20 14:37   ` [REVIEW][PATCH 03/22] signal/c6x: " Eric W. Biederman
2018-04-20 14:37   ` [REVIEW][PATCH 04/22] signal/hexagon: Use force_sig_fault as appropriate Eric W. Biederman
2018-04-20 14:37   ` [REVIEW][PATCH 05/22] signal/m68k: Use force_sig_fault where appropriate Eric W. Biederman
2018-04-20 14:37   ` [REVIEW][PATCH 06/22] signal/microblaze: Remove the commented out force_sig_info in do_page_fault Eric W. Biederman
2018-04-20 14:37   ` [REVIEW][PATCH 07/22] signal/microblaze: Use force_sig_fault where appropriate Eric W. Biederman
2018-04-20 14:37   ` [REVIEW][PATCH 08/22] signal/mips: " Eric W. Biederman
2018-05-09 15:14     ` Matt Redfearn
2018-05-10  2:39       ` Eric W. Biederman
2018-05-10  7:59         ` Matt Redfearn
2018-05-11  2:31           ` Eric W. Biederman
2018-04-20 14:37   ` [REVIEW][PATCH 09/22] signal/nds32: " Eric W. Biederman
2018-04-25 11:29     ` Vincent Chen
2018-04-25 15:57       ` Eric W. Biederman
2018-04-26  1:24         ` Greentime Hu
2018-04-20 14:37   ` [REVIEW][PATCH 10/22] signal/nios2: " Eric W. Biederman
2018-04-20 14:38   ` [REVIEW][PATCH 11/22] signal/openrisc: " Eric W. Biederman
2018-04-20 14:38   ` [REVIEW][PATCH 12/22] signal/parisc: Use force_sig_mceerr " Eric W. Biederman
2018-04-20 14:38   ` [REVIEW][PATCH 13/22] signal/parisc: Use force_sig_fault " Eric W. Biederman
2018-04-21 17:24     ` Helge Deller
2018-04-20 14:38   ` [REVIEW][PATCH 14/22] signal/riscv: " Eric W. Biederman
2018-04-21  7:25     ` Christoph Hellwig
2018-04-24 15:31       ` [REVIEW][PATCH 23/22] signal/riscv: Replace do_trap_siginfo with force_sig_fault Eric W. Biederman
2018-04-23 19:11     ` [REVIEW][PATCH 14/22] signal/riscv: Use force_sig_fault where appropriate Palmer Dabbelt
2018-04-24 15:28       ` Eric W. Biederman
2018-04-20 14:38   ` [REVIEW][PATCH 15/22] signal/s390: " Eric W. Biederman
2018-04-23  5:44     ` Martin Schwidefsky
2018-04-20 14:38   ` [REVIEW][PATCH 16/22] signal/sh: " Eric W. Biederman
2018-04-20 14:55     ` Rich Felker
2018-05-28  9:19       ` Geert Uytterhoeven
2018-05-29 15:00         ` [PATCH] signal/sh: Stop gcc warning about an impossible case in do_divide_error Eric W. Biederman
2018-05-30  7:54           ` Sergei Shtylyov
2018-04-20 14:38   ` [REVIEW][PATCH 17/22] signal/sparc: Use send_sig_fault where appropriate Eric W. Biederman
2018-04-20 14:38   ` [REVIEW][PATCH 18/22] signal/sparc: Use force_sig_fault " Eric W. Biederman
2018-04-20 14:38   ` [REVIEW][PATCH 19/22] signal/um: Use force_sig_fault in relay_signal Eric W. Biederman
2018-04-20 16:06     ` [uml-devel] " Anton Ivanov
2018-04-24  8:32       ` Richard Weinberger
2018-04-24  8:44         ` Anton Ivanov
2018-04-24 15:59           ` Eric W. Biederman
     [not found]             ` <CAMD8JhwgcWCp6c=O4-spNW1VdY5M-eAjr7M5PieeAfeTSe_4yw@mail.gmail.com>
2018-04-24 22:03               ` Martin Pärtel
2018-04-24 22:24                 ` Eric W. Biederman
2018-04-25 23:05                   ` Martin Pärtel
2018-04-28 14:02                     ` [REVIEW][PATCH 0/5] Improving siginfo_layout and fixing uml's relay_signal Eric W. Biederman
2018-04-28 14:06                       ` [REVIEW][PATCH 1/5] signal/signalfd: Remove __put_user from signalfd_copyinfo Eric W. Biederman
2018-04-28 14:06                       ` [REVIEW][PATCH 2/5] signal/signalfd: Add support for SIGSYS Eric W. Biederman
2018-04-28 14:07                       ` [REVIEW][PATCH 3/5] signal: Remove unncessary #ifdef SEGV_PKUERR in 32bit compat code Eric W. Biederman
2018-04-28 14:07                       ` [REVIEW][PATCH 4/5] signal: Extend siginfo_layout with SIL_FAULT_{MCEERR|BNDERR|PKUERR} Eric W. Biederman
2018-04-28 14:07                       ` [REVIEW][PATCH 5/5] signal/um: More carefully relay signals in relay_signal Eric W. Biederman
2018-04-20 14:38   ` [REVIEW][PATCH 20/22] signal/um: Use force_sig_fault where appropriate Eric W. Biederman
2018-04-20 14:38   ` [REVIEW][PATCH 21/22] signal/xtensa: Consistenly use SIGBUS in do_unaligned_user Eric W. Biederman
2018-04-20 16:06     ` Max Filippov
2018-04-20 14:38   ` [REVIEW][PATCH 22/22] signal/xtensa: Use force_sig_fault where appropriate Eric W. Biederman
2018-04-20 16:27     ` Max Filippov

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