From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Layton Subject: Re: [PATCH] cifs: extend the buffer length enought for sprintf() using Date: Fri, 19 Jul 2013 15:48:30 -0400 Message-ID: <20130719154830.4b9d8c39@tlielax.poochiereds.net> References: <51E5E9DA.8020603@asianux.com> <20130719135115.2ebff0cd@tlielax.poochiereds.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Chen Gang , "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 Fri, 19 Jul 2013 15:32:29 -0400 Scott Lovenberg wrote: > On Fri, Jul 19, 2013 at 1:51 PM, Jeff Layton wrote: > > > > On Tue, 16 Jul 2013 21:58:19 -0400 > > 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. > > > > > > > Yep, it probably should be extended out to 256. Send a patch when you > > get a chance and I'll plan to review and merge it. > > > > -- > > Jeff Layton > > > I can get to it this afternoon. :) > > What do you want to do about the conflicting MAX_SHARE_SIZE? The > kernel allows 80, we use 256 in the mount helper. Right now we can > potentially pass in a string that's too long and it'll be kicked back > from the kernel. I guess it could be bad if anyone ever forgets to > check the string before using it on the kernel side. A quick Googling > suggests that the kernel side code is correct > (http://support.microsoft.com/kb/916525) about 80 characters. > > I've made the other MAX_* defines match up with the kernel side > because the mount helper is too conservative with string lengths, this > is the only case where it's too liberal. Sure, sounds fine. Might as well fix up all that you can find... -- Jeff Layton