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[2a0a:edc0:0:900:1d::77] (helo=ptz.office.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtp (Exim 4.94.2) (envelope-from ) id 1poRMc-00Buz1-Gv; Mon, 17 Apr 2023 18:05:58 +0200 Received: from ukl by ptz.office.stw.pengutronix.de with local (Exim 4.94.2) (envelope-from ) id 1poRMb-00DyPg-Px; Mon, 17 Apr 2023 18:05:57 +0200 Date: Mon, 17 Apr 2023 18:05:57 +0200 From: Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= To: George Kennedy Cc: vigneshr@ti.com, eorge.kennedy@oracle.com, richard@nod.at, linux-kernel@vger.kernel.org, stable@vger.kernel.org, syzkaller@googlegroups.com, linux-mtd@lists.infradead.org, harshit.m.mogalapalli@oracle.com, miquel.raynal@bootlin.com, kernel@pengutronix.de Subject: Re: [Regression] Cannot overwrite VID header offset any more [Was: [PATCH] ubi: ensure that VID header offset + VID header size <= alloc, size] Message-ID: <20230417160557.uic7ullodkavjr2x@pengutronix.de> References: <20230417160102.lw6n7bdxwrlkluwj@pengutronix.de> MIME-Version: 1.0 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Content-Disposition: inline --usbftahkxpak76ui Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hello, On Mon, Apr 17, 2023 at 06:01:02PM +0200, Uwe Kleine-K=F6nig wrote: > On Tue, Nov 15, 2022 at 10:14:44AM -0500, George Kennedy wrote: > > Ensure that the VID header offset + VID header size does not exceed > > the allocated area to avoid slab OOB. > >=20 > > BUG: KASAN: slab-out-of-bounds in crc32_body lib/crc32.c:111 [inline] > > BUG: KASAN: slab-out-of-bounds in crc32_le_generic lib/crc32.c:179 [inl= ine] > > BUG: KASAN: slab-out-of-bounds in crc32_le_base+0x58c/0x626 lib/crc32.c= :197 > > Read of size 4 at addr ffff88802bb36f00 by task syz-executor136/1555 > >=20 > > CPU: 2 PID: 1555 Comm: syz-executor136 Tainted: G W > > 6.0.0-1868 #1 > > Hardware name: Red Hat KVM, BIOS 1.13.0-2.module+el8.3.0+7860+a7792d29 > > 04/01/2014 > > Call Trace: > > > > __dump_stack lib/dump_stack.c:88 [inline] > > dump_stack_lvl+0x85/0xad lib/dump_stack.c:106 > > print_address_description mm/kasan/report.c:317 [inline] > > print_report.cold.13+0xb6/0x6bb mm/kasan/report.c:433 > > kasan_report+0xa7/0x11b mm/kasan/report.c:495 > > crc32_body lib/crc32.c:111 [inline] > > crc32_le_generic lib/crc32.c:179 [inline] > > crc32_le_base+0x58c/0x626 lib/crc32.c:197 > > ubi_io_write_vid_hdr+0x1b7/0x472 drivers/mtd/ubi/io.c:1067 > > create_vtbl+0x4d5/0x9c4 drivers/mtd/ubi/vtbl.c:317 > > create_empty_lvol drivers/mtd/ubi/vtbl.c:500 [inline] > > ubi_read_volume_table+0x67b/0x288a drivers/mtd/ubi/vtbl.c:812 > > ubi_attach+0xf34/0x1603 drivers/mtd/ubi/attach.c:1601 > > ubi_attach_mtd_dev+0x6f3/0x185e drivers/mtd/ubi/build.c:965 > > ctrl_cdev_ioctl+0x2db/0x347 drivers/mtd/ubi/cdev.c:1043 > > vfs_ioctl fs/ioctl.c:51 [inline] > > __do_sys_ioctl fs/ioctl.c:870 [inline] > > __se_sys_ioctl fs/ioctl.c:856 [inline] > > __x64_sys_ioctl+0x193/0x213 fs/ioctl.c:856 > > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > do_syscall_64+0x3e/0x86 arch/x86/entry/common.c:80 > > entry_SYSCALL_64_after_hwframe+0x63/0x0 > > RIP: 0033:0x7f96d5cf753d > > Code: > > RSP: 002b:00007fffd72206f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f96d5cf753d > > RDX: 0000000020000080 RSI: 0000000040186f40 RDI: 0000000000000003 > > RBP: 0000000000400cd0 R08: 0000000000000000 R09: 0000000000000000 > > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000400be0 > > R13: 00007fffd72207e0 R14: 0000000000000000 R15: 0000000000000000 > > > >=20 > > Allocated by task 1555: > > kasan_save_stack+0x20/0x3d mm/kasan/common.c:38 > > kasan_set_track mm/kasan/common.c:45 [inline] > > set_alloc_info mm/kasan/common.c:437 [inline] > > ____kasan_kmalloc mm/kasan/common.c:516 [inline] > > __kasan_kmalloc+0x88/0xa3 mm/kasan/common.c:525 > > kasan_kmalloc include/linux/kasan.h:234 [inline] > > __kmalloc+0x138/0x257 mm/slub.c:4429 > > kmalloc include/linux/slab.h:605 [inline] > > ubi_alloc_vid_buf drivers/mtd/ubi/ubi.h:1093 [inline] > > create_vtbl+0xcc/0x9c4 drivers/mtd/ubi/vtbl.c:295 > > create_empty_lvol drivers/mtd/ubi/vtbl.c:500 [inline] > > ubi_read_volume_table+0x67b/0x288a drivers/mtd/ubi/vtbl.c:812 > > ubi_attach+0xf34/0x1603 drivers/mtd/ubi/attach.c:1601 > > ubi_attach_mtd_dev+0x6f3/0x185e drivers/mtd/ubi/build.c:965 > > ctrl_cdev_ioctl+0x2db/0x347 drivers/mtd/ubi/cdev.c:1043 > > vfs_ioctl fs/ioctl.c:51 [inline] > > __do_sys_ioctl fs/ioctl.c:870 [inline] > > __se_sys_ioctl fs/ioctl.c:856 [inline] > > __x64_sys_ioctl+0x193/0x213 fs/ioctl.c:856 > > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > do_syscall_64+0x3e/0x86 arch/x86/entry/common.c:80 > > entry_SYSCALL_64_after_hwframe+0x63/0x0 > >=20 > > The buggy address belongs to the object at ffff88802bb36e00 > > which belongs to the cache kmalloc-256 of size 256 > > The buggy address is located 0 bytes to the right of > > 256-byte region [ffff88802bb36e00, ffff88802bb36f00) > >=20 > > The buggy address belongs to the physical page: > > page:00000000ea4d1263 refcount:1 mapcount:0 mapping:0000000000000000 > > index:0x0 pfn:0x2bb36 > > head:00000000ea4d1263 order:1 compound_mapcount:0 compound_pincount:0 > > flags: 0xfffffc0010200(slab|head|node=3D0|zone=3D1|lastcpupid=3D0x1ffff= f) > > raw: 000fffffc0010200 ffffea000066c300 dead000000000003 ffff888100042b40 > > raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 > > page dumped because: kasan: bad access detected > >=20 > > Memory state around the buggy address: > > ffff88802bb36e00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > ffff88802bb36e80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > > ffff88802bb36f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > > ^ > > ffff88802bb36f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > > ffff88802bb37000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > >=20 > > Fixes: 801c135ce73d ("UBI: Unsorted Block Images") > > Reported-by: syzkaller > > Signed-off-by: George Kennedy > > --- > > drivers/mtd/ubi/build.c | 6 ++++++ > > 1 file changed, 6 insertions(+) > >=20 > > diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c > > index a32050fecabf..53aa4de6b963 100644 > > --- a/drivers/mtd/ubi/build.c > > +++ b/drivers/mtd/ubi/build.c > > @@ -663,6 +663,12 @@ static int io_init(struct ubi_device *ubi, int max= _beb_per1024) > > ubi->ec_hdr_alsize =3D ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size); > > ubi->vid_hdr_alsize =3D ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size= ); > > + if (ubi->vid_hdr_offset && ((ubi->vid_hdr_offset + UBI_VID_HDR_SIZE) > > > + ubi->vid_hdr_alsize)) { > > + ubi_err(ubi, "VID header offset %d too large.", ubi->vid_hdr_offset); > > + return -EINVAL; > > + } > > + >=20 > This patch is in mainline as 1b42b1a36fc946f0d7088425b90d491b4257ca3e, > and backported to various stable releases. >=20 > For me this breaks >=20 > ubiattach -m 0 -O 2048 >=20 > I think the check >=20 > ubi->vid_hdr_offset + UBI_VID_HDR_SIZE > ubi->vid_hdr_alsize >=20 > is wrong. Without -O passed to ubiattach (and dynamic debug enabled) I > get: >=20 > [ 5294.936762] UBI DBG gen (pid 9619): sizeof(struct ubi_ainf_peb) 56 > [ 5294.936769] UBI DBG gen (pid 9619): sizeof(struct ubi_wl_entry) 32 > [ 5294.936774] UBI DBG gen (pid 9619): min_io_size 2048 > [ 5294.936779] UBI DBG gen (pid 9619): max_write_size 2048 > [ 5294.936783] UBI DBG gen (pid 9619): hdrs_min_io_size 512 > [ 5294.936787] UBI DBG gen (pid 9619): ec_hdr_alsize 512 > [ 5294.936791] UBI DBG gen (pid 9619): vid_hdr_alsize 512 > [ 5294.936796] UBI DBG gen (pid 9619): vid_hdr_offset 512 > [ 5294.936800] UBI DBG gen (pid 9619): vid_hdr_aloffset 512 > [ 5294.936804] UBI DBG gen (pid 9619): vid_hdr_shift 0 > [ 5294.936808] UBI DBG gen (pid 9619): leb_start 2048 > [ 5294.936812] UBI DBG gen (pid 9619): max_erroneous 409 >=20 > So the check would only pass for vid_hdr_offset <=3D 512 - > UBI_VID_HDR_SIZE; note that even specifying the default value 512 (i.e. >=20 > ubiattach -m 0 -O 512 >=20 > ) fails the check. >=20 > A less strong check would be: >=20 > diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c > index 0904eb40c95f..69c28a862430 100644 > --- a/drivers/mtd/ubi/build.c > +++ b/drivers/mtd/ubi/build.c > @@ -666,8 +666,8 @@ static int io_init(struct ubi_device *ubi, int max_be= b_per1024) > ubi->ec_hdr_alsize =3D ALIGN(UBI_EC_HDR_SIZE, ubi->hdrs_min_io_size); > ubi->vid_hdr_alsize =3D ALIGN(UBI_VID_HDR_SIZE, ubi->hdrs_min_io_size); > =20 > - if (ubi->vid_hdr_offset && ((ubi->vid_hdr_offset + UBI_VID_HDR_SIZE) > > - ubi->vid_hdr_alsize)) { > + if (ubi->vid_hdr_offset && > + ubi->vid_hdr_offset + UBI_VID_HDR_SIZE > ubi->peb_size) { > ubi_err(ubi, "VID header offset %d too large.", ubi->vid_hdr_offset); > return -EINVAL; > } >=20 > But I'm unsure if this would be too lax?! I just learned in irc that 1e020e1b96af ("ubi: Fix failure attaching when vid_hdr offset equals to (s= ub)page size") is supposed to fix that. Best regards Uwe --=20 Pengutronix e.K. | Uwe Kleine-K=F6nig | Industrial Linux Solutions | https://www.pengutronix.de/ | --usbftahkxpak76ui Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEP4GsaTp6HlmJrf7Tj4D7WH0S/k4FAmQ9bmQACgkQj4D7WH0S /k5pvwgArhhQZtMIqKSLAbg+XyKYFwa5oBHGtxRrenK60JhukhujPXDx291maf37 J1qO+z9ZeeEjfHyaR6hyXxFATCgcdMKWJl85opsvRZsUfdqulUd+TU+R/ovD6WZY sp8eIoau1fLfXkU+L6Dhrw40a6jnp0pr5Nwqme1f0SROnQMU1eEWNjCW6QgoLGrc GGSYwr1SMx8thuiCw97J3aUaxP9ZsUufpGjLm6ZTbltrGnqG9t7WWWfdoIoVUPqq /sPLamQcDtq+2hHsq8WguuLl8vAs4YG6lVjZ2yLCr03b38a9uy/MruECYk7A6YrC +T7ONvQGJGc/r3ux5f72wEipvrrgXg== =zNOU -----END PGP SIGNATURE----- --usbftahkxpak76ui-- --===============0958466369343342470== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/ --===============0958466369343342470==--