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.
--
Peace and Blessings,
-Scott.
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