From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Thomas Garnier <thgarnie@google.com>
Cc: "David Howells" <dhowells@redhat.com>,
"Dave Hansen" <dave.hansen@intel.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Al Viro" <viro@zeniv.linux.org.uk>,
"René Nyffenegger" <mail@renenyffenegger.ch>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Kees Cook" <keescook@chromium.org>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
"David S . Miller" <davem@davemloft.net>,
"Andy Lutomirski" <luto@kernel.org>,
"Ard Biesheuvel" <ard.biesheuvel@linaro.org>,
"Nicolas Pitre" <nicolas.pitre@linaro.org>,
"Petr Mladek" <pmladek@suse.com>,
"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>,
"Sergey Senozhatsky" <sergey.senozhatsky@gmail.com>,
"Helge Deller" <deller@gmx.de>, "Rik van Riel" <riel@redhat.com>,
"Ingo Molnar" <mingo@kernel.org>,
"Oleg Nesterov" <oleg@redhat.com>,
"John Stultz" <john.stultz@linaro.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Pavel Tikhomirov" <ptikhomirov@virtuozzo.com>
Subject: Re: [PATCH v2 1/4] syscalls: Restore address limit after a syscall
Date: Thu, 9 Mar 2017 19:39:12 +0900 [thread overview]
Message-ID: <20170309103911.GA565@jagdpanzerIV.localdomain> (raw)
In-Reply-To: <20170309012456.5631-1-thgarnie@google.com>
Hello,
On (03/08/17 17:24), Thomas Garnier wrote:
> This patch ensures a syscall does not return to user-mode with a kernel
> address limit. If that happened, a process can corrupt kernel-mode
> memory and elevate privileges.
I like the patch set.
a side note (perhaps a bit irrelevant), the WARN backtrace does not
really tell more than "incorrect get_fs() on user-mode return" message
does
incorrect get_fs() on user-mode return
------------[ cut here ]------------
kernel BUG at kernel/sys.c:2467!
invalid opcode: 0000 [#1] PREEMPT SMP
Modules linked in: FOO
CPU: 2 PID: 355 Comm: BAR
Hardware name: BUZ
task: ffff8801329f4e00 task.stack: ffffc900005d8000
RIP: 0010:verify_pre_usermode_state+0x31/0x34
RSP: 0018:ffffc900005dbf48 EFLAGS: 00010096
RAX: 0000000000000026 RBX: 0000000000000002 RCX: 0000000000000001
RDX: 0000000000000046 RSI: ffff880130cead88 RDI: ffffffff81095594
RBP: ffffc900005dbf48 R08: 0000000000000001 R09: 0000000000000001
R10: ffffc900005dbd58 R11: ffff8801329f4e00 R12: 0000000000000002
R13: 0000000000000001 R14: 00007fb6c6a7b5e0 R15: 0000000000000002
FS: 00007fb6c70d3b40(0000) GS:ffff880137d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd9d94f8f8 CR3: 00000001295b2000 CR4: 00000000000006e0
Call Trace:
entry_SYSCALL_64_fastpath+0x3a/0xb2
RIP: 0033:0x7fb6c67ba3c0
RSP: 002b:00007ffd9d94f5c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: 0000000000000002 RBX: 0000000000000000 RCX: 00007fb6c67ba3c0
RDX: 0000000000000002 RSI: 0000000000ba7310 RDI: 0000000000000001
RBP: 0000000000000001 R08: 00007fb6c6a7c740 R09: 00007fb6c70d3b40
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Code: 48 8b 14 25 40 c5 00 00 48 b8 00 f0 ff ff ff 7f 00 00 48 39 82 28 11 00 00 74 12 55 48 c7 c7 9b f5 78 81 48 89 e5 e8 14 19 0b 00 <0f> 0b c3 66 66 66 66 90 55 48 89 e5 53 48 8b 47 50 48 89 fb 48
may be some day someone would be interested in something like
"incorrect get_fs() on user-mode return from %pS"
and set_fs() would save _RET_IP_.
just a side note.
-ss
next prev parent reply other threads:[~2017-03-09 10:39 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-09 1:24 [PATCH v2 1/4] syscalls: Restore address limit after a syscall Thomas Garnier
2017-03-09 1:24 ` [PATCH v2 2/4] x86/syscalls: Specific usage of verify_pre_usermode_state Thomas Garnier
2017-03-09 1:24 ` [PATCH v2 3/4] arm/syscalls: " Thomas Garnier
2017-03-09 1:24 ` [PATCH v2 4/4] arm64/syscalls: " Thomas Garnier
2017-03-09 12:23 ` Mark Rutland
2017-03-09 15:56 ` Thomas Garnier
2017-03-09 16:05 ` Mark Rutland
2017-03-09 16:19 ` Thomas Garnier
2017-03-09 16:26 ` Russell King - ARM Linux
2017-03-09 16:35 ` Thomas Garnier
2017-03-09 17:05 ` Russell King - ARM Linux
2017-03-09 8:42 ` [PATCH v2 1/4] syscalls: Restore address limit after a syscall Borislav Petkov
2017-03-09 15:48 ` Thomas Garnier
2017-03-09 17:27 ` Andy Lutomirski
2017-03-09 17:41 ` Thomas Garnier
2017-03-09 10:39 ` Sergey Senozhatsky [this message]
2017-03-09 12:09 ` Mark Rutland
2017-03-09 13:44 ` Russell King - ARM Linux
2017-03-09 15:21 ` Mark Rutland
2017-03-09 15:54 ` Thomas Garnier
2017-03-09 15:52 ` Thomas Garnier
2017-03-09 12:32 ` Christian Borntraeger
2017-03-09 15:53 ` Thomas Garnier
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