From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chen Gang Subject: Re: [PATCH] cifs: extend the buffer length enought for sprintf() using Date: Wed, 17 Jul 2013 10:07:36 +0800 Message-ID: <51E5FC68.6080302@asianux.com> References: <51E5E9DA.8020603@asianux.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Jeff Layton , "sfrench-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org" , linux-cifs , samba-technical-w/Ol4Ecudpl8XjKLYN78aQ@public.gmane.org To: Scott Lovenberg Return-path: In-Reply-To: Sender: linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: On 07/17/2013 09:58 AM, Scott Lovenberg wrote: > On Tue, Jul 16, 2013 at 8:48 PM, Chen Gang 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 >> > --- >> > 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 >> > -- >> > To unsubscribe from this list: send the line "unsubscribe linux-cifs" in >> > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org >> > More majordomo info at http://vger.kernel.org/majordomo-info.html > 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