On 07/17/2013 09:58 AM, Scott Lovenberg wrote:
> On Tue, Jul 16, 2013 at 8:48 PM, 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..ce2d331 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_CIF_DOMAINNAME)
>> > break;
>> > if (!ses->domainName) {
>> > ses->domainName =
>> > diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
>> > index 33f17ed..88280e0 100644
>> > --- a/fs/cifs/cifsglob.h
>> > +++ b/fs/cifs/cifsglob.h
>> > @@ -396,6 +396,7 @@ struct smb_version_values {
>> >
>> > #define HEADER_SIZE(server) (server->vals->header_size)
>> > #define MAX_HEADER_SIZE(server) (server->vals->max_header_size)
>> > +#define MAX_CIF_DOMAINNAME 256 /* 255 + '\0' */
>> >
>> > struct smb_vol {
>> > char *username;
>> > diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
>> > index fa68813..ed6bf20 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_CIF_DOMAINNAME)
>> > + == MAX_CIF_DOMAINNAME) {
>> > 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_CIF_DOMAINNAME + 1 */
>> > +#define CIFSCREDS_DESC_SIZE (7 + MAX_CIF_DOMAINNAME + 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..106a575 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_CIF_DOMAINNAME, 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_CIF_DOMAINNAME);
>> > + bcc_ptr += strnlen(ses->domainName, MAX_CIF_DOMAINNAME);
>> > } /* else we will send a null domain name
>> > so the server will default to its own domain */
>> > *bcc_ptr = 0;
>> > --
>> > 1.7.7.6
>> > --
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> If this is correct for the domain size, MAX_DOMAIN_SIZE in the
> cifs-utils mount helper (mount.cifs.c) has to be changed. It is
> currently 64 + null terminator. I can open a bug and patch it if this
> is correct.
>
> CC'ing Jeff Layton since he maintains the cifs-utils package.
Thank you very much.
--
Chen Gang
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