linux-kernel - Re: [PATCH] xfs: fix null pointer dereference when mapping is NULL

Open Source and information security mailing list archives

Message-ID: <55E84EDE.2080404@sandeen.net>
Date:	Thu, 3 Sep 2015 08:45:02 -0500
From:	Eric Sandeen <sandeen@...deen.net>
To:	Brian Foster <bfoster@...hat.com>,
	Colin King <colin.king@...onical.com>
Cc:	linux-kernel@...r.kernel.org, xfs@....sgi.com
Subject: Re: [PATCH] xfs: fix null pointer dereference when mapping is NULL

On 9/3/15 5:45 AM, Brian Foster wrote:
> On Thu, Sep 03, 2015 at 10:57:40AM +0100, Colin King wrote:
>> From: Colin Ian King <colin.king@...onical.com>
>>
>> xfs_vm_set_page_dirty checks to see if mapping is NULL however
>> before this unlikely check it already dereferenced mapping when
>> initializing inode. Move the inode initialization after the mapping
>> null check to avoid a potential null pointer dereference.
>>
>> Fixes: 22e757a49cf0 ("xfs: don't dirty buffers beyond EOF")
>> Signed-off-by: Colin Ian King <colin.king@...onical.com>
>> ---
> 
> Reviewed-by: Brian Foster <bfoster@...hat.com>

Reviewed-by: Eric Sandeen <sandeen@...hat.com>

Should probably cc: stable on this one too, the commit it
fixes went in at 3.17, and it also cc'd stable.

-Eric

>>  fs/xfs/xfs_aops.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
>> index c77499b..d15ae85 100644
>> --- a/fs/xfs/xfs_aops.c
>> +++ b/fs/xfs/xfs_aops.c
>> @@ -1935,7 +1935,7 @@ xfs_vm_set_page_dirty(
>>  	struct page		*page)
>>  {
>>  	struct address_space	*mapping = page->mapping;
>> -	struct inode		*inode = mapping->host;
>> +	struct inode		*inode;
>>  	loff_t			end_offset;
>>  	loff_t			offset;
>>  	int			newly_dirty;
>> @@ -1944,6 +1944,7 @@ xfs_vm_set_page_dirty(
>>  	if (unlikely(!mapping))
>>  		return !TestSetPageDirty(page);
>>  
>> +	inode = mapping->host;
>>  	end_offset = i_size_read(inode);
>>  	offset = page_offset(page);
>>  
>> -- 
>> 2.5.0
>>
>> _______________________________________________
>> xfs mailing list
>> xfs@....sgi.com
>> http://oss.sgi.com/mailman/listinfo/xfs
> 
> _______________________________________________
> xfs mailing list
> xfs@....sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs
> 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives