From: Andrew Morton <akpm@linux-foundation.org>
To: Dominique Martinet <asmadeus@codewreck.org>
Cc: Omar Sandoval <osandov@osandov.com>,
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>,
Bhupesh Sharma <bhsharma@redhat.com>,
kernel-team@fb.com
Subject: Re: [PATCH v3] proc/kcore: fix invalid memory access in multi-page read optimization
Date: Wed, 5 Sep 2018 13:57:17 -0700 [thread overview]
Message-ID: <20180905135717.ff763b34c4a3f1ca500d715b@linux-foundation.org> (raw)
In-Reply-To: <1536100702-28706-1-git-send-email-asmadeus@codewreck.org>
On Wed, 5 Sep 2018 00:38:22 +0200 Dominique Martinet <asmadeus@codewreck.org> 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.
>
> ...
>
> --- 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 */
lgtm. Let's add a nice little why-were-doing-this?
--- a/fs/proc/kcore.c~proc-kcore-fix-invalid-memory-access-in-multi-page-read-optimization-v3-fix
+++ a/fs/proc/kcore.c
@@ -464,7 +464,7 @@ read_kcore(struct file *file, char __use
ret = -EFAULT;
goto out;
}
- m = NULL;
+ m = NULL; /* skip the list anchor */
} else if (m->type == KCORE_VMALLOC) {
vread(buf, (char *)start, tsz);
/* we have to zero-fill user buffer even if no read */
_
next prev parent reply other threads:[~2018-09-06 1:29 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
2018-09-05 20:57 ` Andrew Morton [this message]
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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