On Fri, Feb 23, 2018 at 11:24 AM, Steve Dickson <SteveD@xxxxxxxxxx> wrote:
> Hey Olga,
>
> On 02/22/2018 02:28 PM, Olga Kornievskaia wrote:
>> It is possible that userland can pass to the kernel mismatching
>> inputs for the minorversion. like vers=4.1,minorversion=0. Instead
>> of making the kernel responposible for 'choosing' the minorversion,
>> make the userland always responsible for not sending a mismatch.
> I'm thinking this is probably more of mount problem...
Yes the problem is a broken user land sending incorrect arguments but
I still think the kernel needs to do sanity checking on arguments to
prevent this from happening again.
> mount -t nfs4 -o minorversion=0 server:/export /mnt
>
> shouldn't this be a v4.0 mount instead of a 4.2 mount?
Yes I would think this should create a v4.0 mount.
>
> steved.
>
>>
>> Signed-off-by: Olga Kornievskaia <kolga@xxxxxxxxxx>
>> ---
>> fs/nfs/super.c | 10 +++++++++-
>> 1 file changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
>> index 29bacdc..90c0584 100644
>> --- a/fs/nfs/super.c
>> +++ b/fs/nfs/super.c
>> @@ -1207,7 +1207,7 @@ static int nfs_parse_mount_options(char *raw,
>> struct nfs_parsed_mount_data *mnt)
>> {
>> char *p, *string, *secdata;
>> - int rc, sloppy = 0, invalid_option = 0;
>> + int rc, sloppy = 0, invalid_option = 0, minorversion = -1;
>> unsigned short protofamily = AF_UNSPEC;
>> unsigned short mountfamily = AF_UNSPEC;
>>
>> @@ -1419,6 +1419,7 @@ static int nfs_parse_mount_options(char *raw,
>> if (option > NFS4_MAX_MINOR_VERSION)
>> goto out_invalid_value;
>> mnt->minorversion = option;
>> + minorversion = option;
>> break;
>>
>> /*
>> @@ -1655,6 +1656,9 @@ static int nfs_parse_mount_options(char *raw,
>> }
>> }
>>
>> + if (minorversion >= 0 && minorversion != mnt->minorversion)
>> + goto out_mountvers_mismatch;
>> +
>> return 1;
>>
>> out_mountproto_mismatch:
>> @@ -1685,6 +1689,10 @@ static int nfs_parse_mount_options(char *raw,
>> free_secdata(secdata);
>> printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
>> return 0;
>> +out_mountvers_mismatch:
>> + printk(KERN_INFO "NFS: mismatch versions supplied vers=4.%d and "
>> + "minorversion=%d\n", mnt->minorversion, minorversion);
>> + return 0;
>> }
>>
>> /*
>>
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