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Message-ID: <4f35b02968a18e636e1689c9d52729ef63a438f9.camel@redhat.com>
Date: Mon, 24 Jul 2023 12:27:55 -0400
From: Laurence Oberman <loberman@...hat.com>
To: Oleksandr Natalenko <oleksandr@...hat.com>,
linux-kernel@...r.kernel.org
Cc: linux-scsi@...r.kernel.org, Saurav Kashyap <skashyap@...vell.com>,
Javed Hasan <jhasan@...vell.com>,
GR-QLogic-Storage-Upstream@...vell.com,
"James E.J. Bottomley" <jejb@...ux.ibm.com>,
"Martin K. Petersen" <martin.petersen@...cle.com>,
Jozef Bacik <jobacik@...hat.com>, Rob Evers <revers@...hat.com>
Subject: Re: [RFC PATCH 0/3] scsi: qedf: sanitise uaccess
On Mon, 2023-07-24 at 09:03 -0400, Laurence Oberman wrote:
> On Mon, 2023-07-24 at 14:02 +0200, Oleksandr Natalenko wrote:
> > qedf driver, debugfs part of it specifically, touches __user
> > pointers
> > directly for printing out info to userspace via sprintf(), which
> > may
> > cause crash like this:
> >
> > BUG: unable to handle kernel paging request at 00007ffd1d6b43a0
> > IP: [<ffffffffaa7a882a>] string.isra.7+0x6a/0xf0
> > Oops: 0003 [#1] SMP
> > Call Trace:
> > [<ffffffffaa7a9f31>] vsnprintf+0x201/0x6a0
> > [<ffffffffaa7aa556>] sprintf+0x56/0x80
> > [<ffffffffc04227ed>] qedf_dbg_stop_io_on_error_cmd_read+0x6d/0x90
> > [qedf]
> > [<ffffffffaa65bb2f>] vfs_read+0x9f/0x170
> > [<ffffffffaa65cb82>] SyS_pread64+0x92/0xc0
> >
> > Avoid this by preparing the info in a kernel buffer first, either
> > allocated on stack for small printouts, or via vmalloc() for big
> > ones,
> > and then copying it to the userspace properly.
> >
> > I'm not sure how big the vmalloc()'ed buffer should be, and also
> > whether
> > vmalloc()'ing it directly in the _read() function is a good idea,
> > hence
> > RFC prefix.
> >
> > The qedf_dbg_stop_io_on_error_cmd_read()-related patch is actually
> > tested,
> > the rest is compile-tested only.
> >
> > Oleksandr Natalenko (3):
> > scsi: qedf: do not touch __user pointer in
> > qedf_dbg_stop_io_on_error_cmd_read() directly
> > scsi: qedf: do not touch __user pointer in
> > qedf_dbg_debug_cmd_read()
> > directly
> > scsi: qedf: do not touch __user pointer in
> > qedf_dbg_fp_int_cmd_read()
> > directly
> >
> > drivers/scsi/qedf/qedf_dbg.h | 2 ++
> > drivers/scsi/qedf/qedf_debugfs.c | 35 +++++++++++++++++++---------
> > --
> > --
> > 2 files changed, 23 insertions(+), 14 deletions(-)
> >
> > --
> > 2.41.0
> >
>
> I will test the series, the one patch was already tested.
> This was reproduced in our LAB
> Will report back after testing
>
> Regards
> Laurence
For the series: Against 6.5.0-rc3
Makes sense to me and tested.
Reviewed-by: Laurence Oberman <loberman@...hat.com>
Tested-by: Laurence Oberman <loberman@...hat.com>
[root@...storage5 host2]# ls
clear_stats debug driver_stats fp_int io_trace offload_stats
stop_io_on_error
[root@...storage5 host2]# cat stop_io_on_error
false
[root@...storage5 host2]# cat debug
debug mask = 0x2
[root@...storage5 host2]# cat fp_int
Fastpath I/O completions
#0: 792
#1: 1242
#2: 1151
#3: 978
#4: 775
#5: 855
#6: 899
#7: 643
#8: 801
#9: 1013
#10: 956
#11: 678
#12: 703
#13: 817
#14: 932
#15: 614
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