[PATCH] ceph: fix base64 encoded name's length check in ceph_fname_to_usr()

[PATCH] ceph: fix base64 encoded name's length check in ceph_fname_to_usr()

[xiubli]

From: Xiubo Li <xiubli@redhat.com>

The fname->name is based64_encoded names and the max long shouldn't
exceed the NAME_MAX.

The FSCRYPT_BASE64URL_CHARS(NAME_MAX) will be 255 * 4 / 3.

Signed-off-by: Xiubo Li <xiubli@redhat.com>
---

Note:

This patch is bansed on the wip-fscrpt branch in ceph-client repo.


 fs/ceph/crypto.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c
index 5a87e7385d3f..560481b6c964 100644
--- a/fs/ceph/crypto.c
+++ b/fs/ceph/crypto.c
@@ -205,7 +205,7 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname,
 	}
 
 	/* Sanity check that the resulting name will fit in the buffer */
-	if (fname->name_len > FSCRYPT_BASE64URL_CHARS(NAME_MAX))
+	if (fname->name_len > NAME_MAX || fname->ctext_len > NAME_MAX)
 		return -EIO;
 
 	ret = __fscrypt_prepare_readdir(fname->dir);
-- 
2.27.0

Re: [PATCH] ceph: fix base64 encoded name's length check in ceph_fname_to_usr()

[Jeff Layton]

On Fri, 2022-03-11 at 12:15 +0800, xiubli@redhat.com wrote:
> From: Xiubo Li <xiubli@redhat.com>
> 
> The fname->name is based64_encoded names and the max long shouldn't
> exceed the NAME_MAX.
> 
> The FSCRYPT_BASE64URL_CHARS(NAME_MAX) will be 255 * 4 / 3.
> 
> Signed-off-by: Xiubo Li <xiubli@redhat.com>
> ---
> 
> Note:
> 
> This patch is bansed on the wip-fscrpt branch in ceph-client repo.
> 
> 
>  fs/ceph/crypto.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c
> index 5a87e7385d3f..560481b6c964 100644
> --- a/fs/ceph/crypto.c
> +++ b/fs/ceph/crypto.c
> @@ -205,7 +205,7 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname,
>  	}
>  
>  	/* Sanity check that the resulting name will fit in the buffer */
> -	if (fname->name_len > FSCRYPT_BASE64URL_CHARS(NAME_MAX))
> +	if (fname->name_len > NAME_MAX || fname->ctext_len > NAME_MAX)
>  		return -EIO;
>  
>  	ret = __fscrypt_prepare_readdir(fname->dir);

Thanks, Xiubo. Merged into wip-fscrypt branch. For now I've left this as
a separate patch, but I may squash it into the patch that adds
ceph_fname_to_usr eventually.

-- 
Jeff Layton <jlayton@kernel.org>

Re: [PATCH] ceph: fix base64 encoded name's length check in ceph_fname_to_usr()

[Xiubo Li]

On 3/12/22 1:14 AM, Jeff Layton wrote:
> On Fri, 2022-03-11 at 12:15 +0800, xiubli@redhat.com wrote:
>> From: Xiubo Li <xiubli@redhat.com>
>>
>> The fname->name is based64_encoded names and the max long shouldn't
>> exceed the NAME_MAX.
>>
>> The FSCRYPT_BASE64URL_CHARS(NAME_MAX) will be 255 * 4 / 3.
>>
>> Signed-off-by: Xiubo Li <xiubli@redhat.com>
>> ---
>>
>> Note:
>>
>> This patch is bansed on the wip-fscrpt branch in ceph-client repo.
>>
>>
>>   fs/ceph/crypto.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c
>> index 5a87e7385d3f..560481b6c964 100644
>> --- a/fs/ceph/crypto.c
>> +++ b/fs/ceph/crypto.c
>> @@ -205,7 +205,7 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname,
>>   	}
>>   
>>   	/* Sanity check that the resulting name will fit in the buffer */
>> -	if (fname->name_len > FSCRYPT_BASE64URL_CHARS(NAME_MAX))
>> +	if (fname->name_len > NAME_MAX || fname->ctext_len > NAME_MAX)
>>   		return -EIO;
>>   
>>   	ret = __fscrypt_prepare_readdir(fname->dir);
> Thanks, Xiubo. Merged into wip-fscrypt branch. For now I've left this as
> a separate patch, but I may squash it into the patch that adds
> ceph_fname_to_usr eventually.
>
Yeah, sure. Maybe just as one separate patch to help other to understand 
the code here ?

Thanks Jeff.

- Xiubo