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Date:      Sat, 22 Oct 2022 02:32:22 +0100
From:      Jessica Clarke <jrtc27@freebsd.org>
To:        Konstantin Belousov <kostikbel@gmail.com>
Cc:        Kristof Provost <kp@freebsd.org>, src-committers <src-committers@freebsd.org>, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org
Subject:   Re: git: 9cabef3d146e - main - ldd: use direct exec mode unconditionally
Message-ID:  <9248FC86-7ACB-4099-978B-4A58CE68743D@freebsd.org>
In-Reply-To: <Y1NDzW7i1M2wZkFU@kib.kiev.ua>
References:  <202210061550.296FoVrm088661@gitrepo.freebsd.org> <7F982005-246F-4607-A17B-08C81CE65E0B@FreeBSD.org> <Y1KVf9V4rhNmXe/R@kib.kiev.ua> <DD8C0FC6-A66D-4652-BE34-5591A9670181@FreeBSD.org> <Y1KZjqEabsXjw0qc@kib.kiev.ua> <6AEBEA3C-24DD-44AA-8B59-8DCADF62CAFF@FreeBSD.org> <Y1NDzW7i1M2wZkFU@kib.kiev.ua>

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On 22 Oct 2022, at 02:13, Konstantin Belousov <kostikbel@gmail.com> =
wrote:
>=20
> On Fri, Oct 21, 2022 at 03:10:59PM +0200, Kristof Provost wrote:
>> On 21 Oct 2022, at 15:07, Konstantin Belousov wrote:
>>> On Fri, Oct 21, 2022 at 02:54:59PM +0200, Kristof Provost wrote:
>>>> On 21 Oct 2022, at 14:50, Konstantin Belousov wrote:
>>>>> On Fri, Oct 21, 2022 at 02:18:04PM +0200, Kristof Provost wrote:
>>>>>> On 6 Oct 2022, at 17:50, Konstantin Belousov wrote:
>>>>>>> The branch main has been updated by kib:
>>>>>>>=20
>>>>>>> URL: =
https://cgit.FreeBSD.org/src/commit/?id=3D9cabef3d146e9a844813b6bc8952d6cf=
2e9d45e5
>>>>>>>=20
>>>>>>> commit 9cabef3d146e9a844813b6bc8952d6cf2e9d45e5
>>>>>>> Author: Konstantin Belousov <kib@FreeBSD.org>
>>>>>>> AuthorDate: 2022-09-21 13:55:44 +0000
>>>>>>> Commit: Konstantin Belousov <kib@FreeBSD.org>
>>>>>>> CommitDate: 2022-10-06 15:50:26 +0000
>>>>>>>=20
>>>>>>> ldd: use direct exec mode unconditionally
>>>>>>>=20
>>>>>>> Trying to exec malformed or unusual binary, for instance, a
>>>>>>> non-FreeBSD
>>>>>>> ABI, or using a non-standard interpreter, might give
>>>>>>> unexpected
>>>>>>> outcome.
>>>>>>>=20
>>>>>>> Reported by: The UK's National Cyber Security Centre (NCSC)
>>>>>>> Reviewed by: emaste, markj, philip
>>>>>>> Discussed with: jhb
>>>>>>> Sponsored by: The FreeBSD Foundation
>>>>>>> admbug: 991
>>>>>>> PR: 127276, 175339, 231926
>>>>>>> MFC after: 1 week
>>>>>>> Differential revision: https://reviews.freebsd.org/D36650
>>>>>>>=20
>>>>>> This appears to break things for armv7 (running on aarch64).
>>>>>>=20
>>>>>> This manifests while building pfsense (for 3100 / armv7), which =
we
>>>>>> do on an
>>>>>> aarch64 vm (to avoid having to deal with qemu, and because it=E2=80=
=99s
>>>>>> faster).
>>>>>>=20
>>>>>> During that build a couple ports fail to build, including
>>>>>> databases/sqlite3.
>>>>>> It fails running `/usr/bin/ldd -a =
"/wrkdirs/usr/ports/databases/sqlite3/work-default/stage/usr/local/bin/sql=
ite3" =
"/wrkdirs/usr/ports/databases/sqlite3/work-default/stage/usr/local/lib/lib=
sqlite3.so=E2=80=9D`,
>>>>>> which produces:
>>>>>>=20
>>>>>> 	ld-elf.so.1: =
/wrkdirs/usr/ports/databases/sqlite3/work-default/stage/usr/local/bin/sqli=
te3:
>>>>>> mmap of entire address space failed: Cannot allocate memory
>>>>>> 	=
/wrkdirs/usr/ports/databases/sqlite3/work-default/stage/usr/local/bin/sqli=
te3:
>>>>>> exit status 1
>>>>>>=20
>>>>>> That fails doing the `mapbase =3D mmap(base_addr, mapsize, =
PROT_NONE,
>>>>>> base_flags, -1, 0);` call in rtld-elf=E2=80=99s map_object():217.
>>>>>> That call
>>>>>> does
>>>>>> `mmap(0x10000, 0x1dc000, PROT_NONE, 0x6010, -1, 0) =3D> =
0xffffffff`.
>>>>>>=20
>>>>>> With this patch reverted we can build successfully.
>>>>>=20
>>>>> Can you manually invoke ldd on the binary under ktrace -i, and
>>>>> show me
>>>>> the
>>>>> kdump output?
>>>>>=20
>>>> I might be doing something wrong:
>>>>=20
>>>> 	# ktrace -i /usr/obj/usr/src/arm.armv7/usr.bin/ldd/ldd -a =
"/wrkdirs/usr/ports/databases/sqlite3/work-default/stage/usr/local/bin/sql=
ite3"
>>>> 	ld-elf.so.1: =
/wrkdirs/usr/ports/databases/sqlite3/work-default/stage/usr/local/bin/sqli=
te3:
>>>> mmap of entire address space failed: Cannot allocate memory
>>>> 	=
/wrkdirs/usr/ports/databases/sqlite3/work-default/stage/usr/local/bin/sqli=
te3:
>>>> exit status 1
>>>> 	# kdump -f ktrace.out
>>>> 	 16 @ UNKNOWN(265)
>>>> 	kdump: data too short
>>>> 	#
>>>>=20
>>>> Perhaps because this is running in a jail?
>>> You need to run host-native kdump, because your kernel is arm64, I
>>> guess.
>>>=20
>> That seemed to do the trick:
>=20
> Please try something along this lines:
>=20
> diff --git a/sys/arm64/include/elf.h b/sys/arm64/include/elf.h
> index 3f7c3964d428..22e968c632bf 100644
> --- a/sys/arm64/include/elf.h
> +++ b/sys/arm64/include/elf.h
> @@ -86,7 +86,7 @@ __ElfType(Auxinfo);
> #endif
>=20
> #if __ELF_WORD_SIZE =3D=3D 32
> -#define	ET_DYN_LOAD_ADDR 0x12000
> +#define	ET_DYN_LOAD_ADDR 0x01001000
> #else
> #define	ET_DYN_LOAD_ADDR 0x100000
> #endif

Ouch... sys/arm=E2=80=99s is better at 0x500000 but that=E2=80=99s still =
only ~4.9 MiB
above LLD=E2=80=99s default image base of 0x10000 so I could see that =
being hit
a bunch. Then again 0x01001000 only gives ~15.9 MiB, which isn=E2=80=99t =
great,
but other architectures seem bad too...

Jess




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