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From: "Eric W. Biederman" <ebiederm@xmission.com>
To: linux-kernel@vger.kernel.org
Cc: Al Viro <viro@zeniv.linux.org.uk>,
	Oleg Nesterov <oleg@redhat.com>,
	linux-arch@vger.kernel.org,
	"Eric W. Biederman" <ebiederm@xmission.com>
Subject: [PATCH 10/11] signal: Introduce clear_siginfo
Date: Thu, 11 Jan 2018 18:59:39 -0600	[thread overview]
Message-ID: <20180112005940.23279-10-ebiederm@xmission.com> (raw)
In-Reply-To: <87373b6ghs.fsf@xmission.com>

Unfortunately struct siginfo has holes both in the common part of the
structure, in the union members, and in the lack of padding of the
union members.  The result of those wholes is that the C standard does
not guarantee those bits will be initialized.  As struct siginfo is
for communication between the kernel and userspace that is a problem.

Add the helper function clear_siginfo that is guaranteed to clear all of
the bits in struct siginfo so when the structure is copied there is no danger
of copying old kernel data and causing a leak of information from kernel
space to userspace.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 include/linux/signal.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/signal.h b/include/linux/signal.h
index 8037b503ce91..87abf0c29ed7 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -16,6 +16,11 @@ static inline void copy_siginfo(struct siginfo *to, const struct siginfo *from)
 	memcpy(to, from, sizeof(*to));
 }
 
+static inline void clear_siginfo(struct siginfo *info)
+{
+	memset(info, 0, sizeof(*info));
+}
+
 int copy_siginfo_to_user(struct siginfo __user *to, const struct siginfo *from);
 
 enum siginfo_layout {
-- 
2.14.1

  parent reply	other threads:[~2018-01-12  1:01 UTC|newest]

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-12  0:57 [PATCH 00/11] siginfo fixes/cleanups esp SI_USER Eric W. Biederman
2018-01-12  0:59 ` [PATCH 01/11] signal: Simplify and fix kdb_send_sig Eric W. Biederman
2018-01-12  0:59 ` [PATCH 02/11] signal/sh: Ensure si_signo is initialized in do_divide_error Eric W. Biederman
2018-01-12  0:59 ` [PATCH 03/11] signal/openrisc: Fix do_unaligned_access to send the proper signal Eric W. Biederman
2018-01-12 13:25   ` Stafford Horne
2018-01-12 17:37     ` Eric W. Biederman
2018-01-12  0:59 ` [PATCH 04/11] signal/parisc: Document a conflict with SI_USER with SIGFPE Eric W. Biederman
2018-01-12 22:29   ` Helge Deller
2018-01-13 21:06     ` Eric W. Biederman
2018-01-14  1:46       ` Eric W. Biederman
2018-02-23  0:15     ` Eric W. Biederman
2018-02-25 19:49       ` Helge Deller
2018-02-27  2:19         ` Eric W. Biederman
2018-01-12  0:59 ` [PATCH 05/11] signal/metag: " Eric W. Biederman
2018-01-12  0:59 ` [PATCH 06/11] signal/powerpc: Document conflicts with SI_USER and SIGFPE and SIGTRAP Eric W. Biederman
2018-01-12  0:59 ` [PATCH 07/11] signal/arm64: Document conflicts with SI_USER and SIGFPE,SIGTRAP,SIGBUS Eric W. Biederman
2018-01-15 16:30   ` [PATCH 07/11] signal/arm64: Document conflicts with SI_USER and SIGFPE, SIGTRAP, SIGBUS Dave Martin
2018-01-15 17:23     ` Eric W. Biederman
2018-01-16 17:24       ` Dave Martin
2018-01-16 22:28         ` Eric W. Biederman
2018-01-17 11:46           ` Dave Martin
2018-01-17 11:57           ` Russell King - ARM Linux
2018-01-17 12:15             ` Dave Martin
2018-01-17 12:37               ` Russell King - ARM Linux
2018-01-17 15:37                 ` Dave Martin
2018-01-17 15:49                   ` Russell King - ARM Linux
2018-01-17 16:11                     ` Dave Martin
2018-01-17 16:45                 ` Eric W. Biederman
2018-01-17 17:14                   ` Russell King - ARM Linux
2018-01-24 21:28                     ` Eric W. Biederman
2018-01-17 17:17       ` Dave Martin
2018-01-17 17:24         ` Eric W. Biederman
2018-01-17 17:39           ` Dave Martin
2018-01-15 19:30     ` James Morse
2018-01-12  0:59 ` [PATCH 08/11] signal/arm: Document conflicts with SI_USER and SIGFPE Eric W. Biederman
2018-01-15 17:49   ` Russell King - ARM Linux
2018-01-15 20:12     ` Eric W. Biederman
2018-01-16 17:41     ` Dave Martin
2018-01-19 12:05     ` Dave Martin
2018-01-12  0:59 ` [PATCH 09/11] signal: Reduce copy_siginfo to just a memcpy Eric W. Biederman
2018-01-12  0:59 ` Eric W. Biederman [this message]
2018-01-12  0:59 ` [PATCH 11/11] signal: Ensure generic siginfos the kernel sends have all bits initialized Eric W. Biederman
2018-01-12 20:29 ` [PATCH 0/2] siginfo fixes Eric W. Biederman
2018-01-12 20:31   ` [PATCH 1/2] mn10300/misalignment: Use SIGSEGV SEGV_MAPERR to report a failed user copy Eric W. Biederman
2018-01-12 20:31   ` [PATCH 2/2] x86/mm/pkeys: Fix fill_sig_info_pkey Eric W. Biederman
2018-01-14 11:44     ` [tip:x86/urgent] " tip-bot for Eric W. Biederman
2018-01-16  0:39   ` [PATCH 00/22] siginfo unification Eric W. Biederman
2018-01-16  0:39     ` [PATCH 01/22] signal: Document all of the signals that use the _sigfault union member Eric W. Biederman
2018-01-16  0:39     ` [PATCH 02/22] signal: Document the strange si_codes used by ptrace event stops Eric W. Biederman
2018-01-16  0:39     ` [PATCH 03/22] signal: Document glibc's si_code of SI_ASYNCNL Eric W. Biederman
2018-01-16  0:39     ` [PATCH 04/22] signal: Ensure no siginfo union member increases the size of struct siginfo Eric W. Biederman
2018-01-16  0:39     ` [PATCH 05/22] signal: Clear si_sys_private before copying siginfo to userspace Eric W. Biederman
2018-01-16  0:39     ` [PATCH 06/22] signal: Remove _sys_private and _overrun_incr from struct compat_siginfo Eric W. Biederman
2018-01-16  0:39     ` [PATCH 07/22] ia64/signal: switch to generic struct siginfo Eric W. Biederman
2018-01-16  0:39     ` [PATCH 08/22] signal/ia64: switch the last arch-specific copy_siginfo_to_user() to generic version Eric W. Biederman
2018-01-16  0:39     ` [PATCH 09/22] signal/mips: switch mips to generic siginfo Eric W. Biederman
2018-01-16  0:39     ` [PATCH 10/22] signal: Remove unnecessary ifdefs now that there is only one struct siginfo Eric W. Biederman
2018-01-16  0:39     ` [PATCH 11/22] signal: kill __ARCH_SI_UID_T Eric W. Biederman
2018-01-16  0:39     ` [PATCH 12/22] signal: unify compat_siginfo_t Eric W. Biederman
2018-01-16  0:40     ` [PATCH 13/22] signal: Move addr_lsb into the _sigfault union for clarity Eric W. Biederman
2018-03-16 19:00       ` Dave Hansen
2018-03-16 19:24         ` Dave Hansen
2018-03-16 20:06           ` Eric W. Biederman
2018-03-16 20:33             ` Dave Hansen
2018-03-16 21:08               ` Eric W. Biederman
2018-01-16  0:40     ` [PATCH 14/22] signal/powerpc: Remove redefinition of NSIGTRAP on powerpc Eric W. Biederman
2018-01-16  0:40     ` [PATCH 15/22] signal/ia64: Move the ia64 specific si_codes to asm-generic/siginfo.h Eric W. Biederman
2018-01-16  0:40     ` [PATCH 16/22] signal/frv: Move the frv " Eric W. Biederman
2018-01-16  0:40     ` [PATCH 17/22] signal/tile: Move the tile " Eric W. Biederman
2018-01-16  0:40     ` [PATCH 18/22] signal/blackfin: Move the blackfin " Eric W. Biederman
2018-01-16  0:40     ` [PATCH 19/22] signal/blackfin: Remove pointless UID16_SIGINFO_COMPAT_NEEDED Eric W. Biederman
2018-01-16  0:40     ` [PATCH 20/22] signal: Unify and correct copy_siginfo_from_user32 Eric W. Biederman
2018-01-16  0:40     ` [PATCH 21/22] signal: Remove the code to clear siginfo before calling copy_siginfo_from_user32 Eric W. Biederman
2018-01-16  0:40     ` [PATCH 22/22] signal: Unify and correct copy_siginfo_to_user32 Eric W. Biederman
2018-01-19 18:03       ` Al Viro
2018-01-19 21:04         ` Eric W. Biederman
2018-01-23 21:05     ` [PATCH 00/10] siginfo infrastructure Eric W. Biederman
2018-01-23 21:07       ` [PATCH 01/10] ptrace: Use copy_siginfo in setsiginfo and getsiginfo Eric W. Biederman
2018-01-23 21:07       ` [PATCH 02/10] signal/arm64: Better isolate the COMPAT_TASK portion of ptrace_hbptriggered Eric W. Biederman
2018-01-23 21:07       ` [PATCH 03/10] signal: Don't use structure initializers for struct siginfo Eric W. Biederman
2018-01-23 21:07       ` [PATCH 04/10] signal: Replace memset(info,...) with clear_siginfo for clarity Eric W. Biederman
2018-01-23 21:07       ` [PATCH 05/10] signal: Add send_sig_fault and force_sig_fault Eric W. Biederman
2018-01-23 21:07       ` [PATCH 06/10] signal: Helpers for faults with specialized siginfo layouts Eric W. Biederman
2018-01-24 19:26         ` Ram Pai
2018-01-24 20:54           ` Eric W. Biederman
2018-01-23 21:07       ` [PATCH 07/10] signal/powerpc: Remove unnecessary signal_code parameter of do_send_trap Eric W. Biederman
2018-01-23 21:07       ` [PATCH 08/10] signal/ptrace: Add force_sig_ptrace_errno_trap and use it where needed Eric W. Biederman
2018-01-23 21:07       ` [PATCH 09/10] mm/memory_failure: Remove unused trapno from memory_failure Eric W. Biederman
2018-01-23 21:07       ` [PATCH 10/10] signal/memory-failure: Use force_sig_mceerr and send_sig_mceerr Eric W. Biederman

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