On 07/19/2013 06:45 PM, Jeff Layton wrote:
> On Fri, 19 Jul 2013 09:01:36 +0800
> Chen Gang <gang.chen@xxxxxxxxxxx> wrote:
>
>> For cifs_set_cifscreds() in "fs/cifs/connect.c", 'desc' buffer length
>> is 'CIFSCREDS_DESC_SIZE' (56 is less than 256), and 'ses->domainName'
>> length may be "255 + '\0'".
>>
>> The related sprintf() may cause memory overflow, so need extend related
>> buffer enough to hold all things.
>>
>> It is also necessary to be sure of 'ses->domainName' must be less than
>> 256, and define the related macro instead of hard code number '256'.
>>
>> Signed-off-by: Chen Gang <gang.chen@xxxxxxxxxxx>
>> ---
>> fs/cifs/cifsencrypt.c | 2 +-
>> fs/cifs/cifsglob.h | 1 +
>> fs/cifs/connect.c | 7 ++++---
>> fs/cifs/sess.c | 6 +++---
>> 4 files changed, 9 insertions(+), 7 deletions(-)
>>
>> diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
>> index 45e57cc..bb84d7c 100644
>> --- a/fs/cifs/cifsencrypt.c
>> +++ b/fs/cifs/cifsencrypt.c
>> @@ -421,7 +421,7 @@ find_domain_name(struct cifs_ses *ses, const struct nls_table *nls_cp)
>> if (blobptr + attrsize > blobend)
>> break;
>> if (type == NTLMSSP_AV_NB_DOMAIN_NAME) {
>> - if (!attrsize)
>> + if (!attrsize || attrsize >= MAX_DOMAINNAME_SIZE)
>> break;
>> if (!ses->domainName) {
>> ses->domainName =
>> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
>> index 33f17ed..64bb4c5 100644
>> --- a/fs/cifs/cifsglob.h
>> +++ b/fs/cifs/cifsglob.h
>> @@ -44,6 +44,7 @@
>> #define MAX_TREE_SIZE (2 + MAX_SERVER_SIZE + 1 + MAX_SHARE_SIZE + 1)
>> #define MAX_SERVER_SIZE 15
>> #define MAX_SHARE_SIZE 80
>> +#define MAX_DOMAINNAME_SIZE 256 /* maximum fully qualified domain name (FQDN) */
>> #define MAX_USERNAME_SIZE 256 /* reasonable maximum for current servers */
>> #define MAX_PASSWORD_SIZE 512 /* max for windows seems to be 256 wide chars */
>>
>> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
>> index fa68813..3f9dcf7 100644
>> --- a/fs/cifs/connect.c
>> +++ b/fs/cifs/connect.c
>> @@ -1675,7 +1675,8 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
>> if (string == NULL)
>> goto out_nomem;
>>
>> - if (strnlen(string, 256) == 256) {
>> + if (strnlen(string, MAX_DOMAINNAME_SIZE)
>> + == MAX_DOMAINNAME_SIZE) {
>> printk(KERN_WARNING "CIFS: domain name too"
>> " long\n");
>> goto cifs_parse_mount_err;
>> @@ -2276,8 +2277,8 @@ cifs_put_smb_ses(struct cifs_ses *ses)
>>
>> #ifdef CONFIG_KEYS
>>
>> -/* strlen("cifs:a:") + INET6_ADDRSTRLEN + 1 */
>> -#define CIFSCREDS_DESC_SIZE (7 + INET6_ADDRSTRLEN + 1)
>> +/* strlen("cifs:a:") + MAX_DOMAINNAME_SIZE + 1 */
>> +#define CIFSCREDS_DESC_SIZE (7 + MAX_DOMAINNAME_SIZE + 1)
>>
>> /* Populate username and pw fields from keyring if possible */
>> static int
>> diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
>> index 79358e3..57b1537 100644
>> --- a/fs/cifs/sess.c
>> +++ b/fs/cifs/sess.c
>> @@ -197,7 +197,7 @@ static void unicode_domain_string(char **pbcc_area, struct cifs_ses *ses,
>> bytes_ret = 0;
>> } else
>> bytes_ret = cifs_strtoUTF16((__le16 *) bcc_ptr, ses->domainName,
>> - 256, nls_cp);
>> + MAX_DOMAINNAME_SIZE, nls_cp);
>> bcc_ptr += 2 * bytes_ret;
>> bcc_ptr += 2; /* account for null terminator */
>>
>> @@ -255,8 +255,8 @@ static void ascii_ssetup_strings(char **pbcc_area, struct cifs_ses *ses,
>>
>> /* copy domain */
>> if (ses->domainName != NULL) {
>> - strncpy(bcc_ptr, ses->domainName, 256);
>> - bcc_ptr += strnlen(ses->domainName, 256);
>> + strncpy(bcc_ptr, ses->domainName, MAX_DOMAINNAME_SIZE);
>> + bcc_ptr += strnlen(ses->domainName, MAX_DOMAINNAME_SIZE);
>> } /* else we will send a null domain name
>> so the server will default to its own domain */
>> *bcc_ptr = 0;
>
> Looks good...
>
> Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
>
>
Thanks.
--
Chen Gang
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