From: mingo@kernel•org (Ingo Molnar)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 0/9] mm: Hardened usercopy
Date: Sat, 9 Jul 2016 09:55:40 +0200 [thread overview]
Message-ID: <20160709075539.GA27852@gmail.com> (raw)
In-Reply-To: <1468032243.13253.59.camel@redhat.com>
* Rik van Riel <riel@redhat•com> wrote:
> On Fri, 2016-07-08 at 19:22 -0700, Laura Abbott wrote:
> >?
> > Even with the SLUB fixup I'm still seeing this blow up on my arm64
> > system. This is a
> > Fedora rawhide kernel + the patches
> >
> > [????0.666700] usercopy: kernel memory exposure attempt detected from
> > fffffc0008b4dd58 (<kernel text>) (8 bytes)
> > [????0.666720] CPU: 2 PID: 79 Comm: modprobe Tainted:
> > G????????W???????4.7.0-0.rc6.git1.1.hardenedusercopy.fc25.aarch64 #1
> > [????0.666733] Hardware name: AppliedMicro Mustang/Mustang, BIOS
> > 1.1.0 Nov 24 2015
> > [????0.666744] Call trace:
> > [????0.666756] [<fffffc0008088a20>] dump_backtrace+0x0/0x1e8
> > [????0.666765] [<fffffc0008088c2c>] show_stack+0x24/0x30
> > [????0.666775] [<fffffc0008455344>] dump_stack+0xa4/0xe0
> > [????0.666785] [<fffffc000828d874>] __check_object_size+0x6c/0x230
> > [????0.666795] [<fffffc00083a5748>] create_elf_tables+0x74/0x420
> > [????0.666805] [<fffffc00082fb1f0>] load_elf_binary+0x828/0xb70
> > [????0.666814] [<fffffc0008298b4c>] search_binary_handler+0xb4/0x240
> > [????0.666823] [<fffffc0008299864>] do_execveat_common+0x63c/0x950
> > [????0.666832] [<fffffc0008299bb4>] do_execve+0x3c/0x50
> > [????0.666841] [<fffffc00080e3720>]
> > call_usermodehelper_exec_async+0xe8/0x148
> > [????0.666850] [<fffffc0008084a80>] ret_from_fork+0x10/0x50
> >
> > This happens on every call to execve. This seems to be the first
> > copy_to_user in
> > create_elf_tables. I didn't get a chance to debug and I'm going out
> > of town
> > all of next week so all I have is the report unfortunately. config
> > attached.
>
> That's odd, this should be copying a piece of kernel data (not text)
> to userspace.
>
> from fs/binfmt_elf.c
>
> ? ? ? ? const char *k_platform = ELF_PLATFORM;
>
> ...
> ? ? ? ? ? ? ? ? size_t len = strlen(k_platform) + 1;
>
> ? ? ? ? ? ? ? ? u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
> ????????????????if (__copy_to_user(u_platform, k_platform, len))
> ????????????????????????return -EFAULT;
>
> from arch/arm/include/asm/elf.h:
>
> #define ELF_PLATFORM_SIZE 8
> #define ELF_PLATFORM????(elf_platform)
>
> extern char elf_platform[];
>
> from arch/arm/kernel/setup.c:
>
> char elf_platform[ELF_PLATFORM_SIZE];
> EXPORT_SYMBOL(elf_platform);
>
> ...
>
> ????????snprintf(elf_platform, ELF_PLATFORM_SIZE, "%s%c",
> ?????????????????list->elf_name, ENDIANNESS);
>
> How does that end up in the .text section of the
> image, instead of in one of the various data sections?
>
> What kind of linker oddity is going on with ARM?
I think the crash happened on ARM64, not ARM.
Thanks,
Ingo
next prev parent reply other threads:[~2016-07-09 7:55 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-06 22:25 [PATCH 0/9] mm: Hardened usercopy Kees Cook
2016-07-06 22:25 ` [PATCH 1/9] " Kees Cook
2016-07-07 5:37 ` Baruch Siach
2016-07-07 17:25 ` Kees Cook
2016-07-07 18:35 ` Baruch Siach
2016-07-07 7:42 ` Thomas Gleixner
2016-07-07 17:29 ` Kees Cook
2016-07-07 19:34 ` Thomas Gleixner
2016-07-07 8:01 ` Arnd Bergmann
2016-07-07 17:37 ` Kees Cook
2016-07-08 9:22 ` Arnd Bergmann
2016-07-07 16:19 ` Rik van Riel
2016-07-07 16:35 ` Rik van Riel
2016-07-07 17:41 ` Kees Cook
2016-07-06 22:25 ` [PATCH 2/9] x86/uaccess: Enable hardened usercopy Kees Cook
2016-07-06 22:25 ` [PATCH 3/9] ARM: uaccess: " Kees Cook
2016-07-06 22:25 ` [PATCH 4/9] arm64/uaccess: " Kees Cook
2016-07-07 10:07 ` Mark Rutland
2016-07-07 17:19 ` Kees Cook
2016-07-06 22:25 ` [PATCH 5/9] ia64/uaccess: " Kees Cook
2016-07-06 22:25 ` [PATCH 6/9] powerpc/uaccess: " Kees Cook
2016-07-06 22:25 ` [PATCH 7/9] sparc/uaccess: " Kees Cook
2016-07-06 22:25 ` [PATCH 8/9] mm: SLAB hardened usercopy support Kees Cook
2016-07-06 22:25 ` [PATCH 9/9] mm: SLUB " Kees Cook
2016-07-07 7:30 ` [PATCH 0/9] mm: Hardened usercopy Christian Borntraeger
2016-07-07 17:27 ` Kees Cook
2016-07-08 8:46 ` Ingo Molnar
2016-07-08 16:19 ` Linus Torvalds
2016-07-08 18:23 ` Ingo Molnar
[not found] ` <b113b487-acc6-24b8-d58c-425d3c884f4c@redhat.com>
2016-07-09 2:44 ` Rik van Riel
2016-07-09 7:55 ` Ingo Molnar [this message]
2016-07-09 8:25 ` Ard Biesheuvel
2016-07-09 17:03 ` Kees Cook
2016-07-09 17:01 ` Kees Cook
2016-07-09 21:27 ` Andy Lutomirski
2016-07-09 23:16 ` PaX Team
2016-07-10 9:16 ` Ingo Molnar
2016-07-10 12:03 ` PaX Team
2016-07-10 12:38 ` Andy Lutomirski
2016-07-11 18:40 ` Kees Cook
2016-07-11 18:34 ` Kees Cook
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