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From: Bhupesh Sharma <bhsharma@redhat.com>
To: Omar Sandoval <osandov@osandov.com>
Cc: Dominique Martinet <asmadeus@codewreck.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-fsdevel@vger.kernel.org,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Eric Biederman <ebiederm@xmission.com>,
	James Morse <james.morse@arm.com>,
	kernel-team@fb.com
Subject: Re: [PATCH v3] proc/kcore: fix invalid memory access in multi-page read optimization
Date: Thu, 6 Sep 2018 01:26:47 +0530	[thread overview]
Message-ID: <CACi5LpNVCXXPnWMAabUxFBKW7R9rH5vKVE0DZ3NENOM_nFAZrw@mail.gmail.com> (raw)
In-Reply-To: <20180904224150.GD24406@vader>

On Wed, Sep 5, 2018 at 4:11 AM, Omar Sandoval <osandov@osandov.com> wrote:
> On Wed, Sep 05, 2018 at 12:38:22AM +0200, Dominique Martinet wrote:
>> The 'm' kcore_list item could point to kclist_head, and it is incorrect to
>> look at m->addr / m->size in this case.
>> There is no choice but to run through the list of entries for every address
>> if we did not find any entry in the previous iteration
>>
>> Reset 'm' to NULL in that case at Omar Sandoval's suggestion.
>>
>> Fixes: bf991c2231117 ("proc/kcore: optimize multiple page reads")
>
> Reviewed-by: Omar Sandoval <osandov@fb.com>
>
> Thanks again for catching this!
>
>> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
>> ---
>>
>> Sorry, resent v2 because From didn't match sob tag
>>
>>  fs/proc/kcore.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
>> index ad72261ee3fe..578926032880 100644
>> --- a/fs/proc/kcore.c
>> +++ b/fs/proc/kcore.c
>> @@ -464,6 +464,7 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
>>                               ret = -EFAULT;
>>                               goto out;
>>                       }
>> +                     m = NULL;
>>               } else if (m->type == KCORE_VMALLOC) {
>>                       vread(buf, (char *)start, tsz);
>>                       /* we have to zero-fill user buffer even if no read */
>> --
>> 2.17.1

Looks sane to me, so:

Reviewed-by: Bhupesh Sharma <bhsharma@redhat.com>

Thanks.

  reply	other threads:[~2018-09-06  0:28 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-18 22:58 [PATCH v3 0/8] /proc/kcore improvements Omar Sandoval
2018-07-18 22:58 ` [PATCH v3 1/8] proc/kcore: don't grab lock for kclist_add() Omar Sandoval
2018-07-18 22:58 ` [PATCH v3 2/8] proc/kcore: don't grab lock for memory hotplug notifier Omar Sandoval
2018-07-18 22:58 ` [PATCH v3 3/8] proc/kcore: replace kclist_lock rwlock with rwsem Omar Sandoval
2018-07-18 22:58 ` [PATCH v3 4/8] proc/kcore: fix memory hotplug vs multiple opens race Omar Sandoval
2018-07-18 22:58 ` [PATCH v3 5/8] proc/kcore: hold lock during read Omar Sandoval
2018-07-24 15:11   ` Tetsuo Handa
2018-07-25 23:34     ` Omar Sandoval
2018-07-18 22:58 ` [PATCH v3 6/8] proc/kcore: clean up ELF header generation Omar Sandoval
2018-07-18 22:58 ` [PATCH v3 7/8] proc/kcore: optimize multiple page reads Omar Sandoval
2018-08-28 10:59   ` KASAN error in " Dominique Martinet
2018-08-29  4:04     ` [PATCH] proc/kcore: fix invalid memory access in multi-page read optimization Dominique Martinet
2018-09-04 18:03       ` Omar Sandoval
2018-09-04 22:24         ` Dominique Martinet
2018-09-04 22:35       ` [PATCH v2] " Dominique Martinet
2018-09-04 22:38         ` [PATCH v3] " Dominique Martinet
2018-09-04 22:41           ` Omar Sandoval
2018-09-05 19:56             ` Bhupesh Sharma [this message]
2018-09-05 20:57           ` Andrew Morton
2018-09-05 22:00             ` Dominique Martinet
2018-07-18 22:58 ` [PATCH v3 8/8] proc/kcore: add vmcoreinfo note to /proc/kcore Omar Sandoval

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