2014-04-28 10:59:30

by Dan Carpenter

Subject: [patch 2/2 v2] staging: lustre: integer overflow in obd_ioctl_is_invalid()

The obd_ioctl_getdata() function caps "data->ioc_len" at
OBD_MAX_IOCTL_BUFFER and then calls this obd_ioctl_is_invalid() to check
that the other values inside data are valid.

There are several lengths inside data but when they are added together
they must not be larger than "data->ioc_len". The checks against
"(data->ioc_inllen1 > (1<<30))" are supposed to ensure that the addition
does not have an integer overflow. But "(1<<30) * 4" actually can
overflow 32 bits, so the checks are insufficient.

I have changed it to "> OBD_MAX_IOCTL_BUFFER" instead.

Signed-off-by: Dan Carpenter <[email protected]>
---
v2: Updated the error messages as Walter Harms pointed out.

diff --git a/drivers/staging/lustre/lustre/include/lustre_lib.h b/drivers/staging/lustre/lustre/include/lustre_lib.h
index bdc9812..3c26bbd 100644
--- a/drivers/staging/lustre/lustre/include/lustre_lib.h
+++ b/drivers/staging/lustre/lustre/include/lustre_lib.h
@@ -179,24 +179,25 @@ static inline int obd_ioctl_packlen(struct obd_ioctl_data *data)

static inline int obd_ioctl_is_invalid(struct obd_ioctl_data *data)
{
- if (data->ioc_len > (1<<30)) {
- CERROR("OBD ioctl: ioc_len larger than 1<<30\n");
+ if (data->ioc_len > OBD_MAX_IOCTL_BUFFER) {
+ CERROR("OBD ioctl: ioc_len larger than %d\n",
+ OBD_MAX_IOCTL_BUFFER);
return 1;
}
- if (data->ioc_inllen1 > (1<<30)) {
- CERROR("OBD ioctl: ioc_inllen1 larger than 1<<30\n");
+ if (data->ioc_inllen1 > OBD_MAX_IOCTL_BUFFER) {
+ CERROR("OBD ioctl: ioc_inllen1 larger than ioc_len\n");
return 1;
}
- if (data->ioc_inllen2 > (1<<30)) {
- CERROR("OBD ioctl: ioc_inllen2 larger than 1<<30\n");
+ if (data->ioc_inllen2 > OBD_MAX_IOCTL_BUFFER) {
+ CERROR("OBD ioctl: ioc_inllen2 larger than ioc_len\n");
return 1;
}
- if (data->ioc_inllen3 > (1<<30)) {
- CERROR("OBD ioctl: ioc_inllen3 larger than 1<<30\n");
+ if (data->ioc_inllen3 > OBD_MAX_IOCTL_BUFFER) {
+ CERROR("OBD ioctl: ioc_inllen3 larger than ioc_len\n");
return 1;
}
- if (data->ioc_inllen4 > (1<<30)) {
- CERROR("OBD ioctl: ioc_inllen4 larger than 1<<30\n");
+ if (data->ioc_inllen4 > OBD_MAX_IOCTL_BUFFER) {
+ CERROR("OBD ioctl: ioc_inllen4 larger than ioc_len\n");
return 1;
}
if (data->ioc_inlbuf1 && !data->ioc_inllen1) {

2014-04-28 11:35:30

by walter harms

Subject: Re: [patch 2/2 v2] staging: lustre: integer overflow in obd_ioctl_is_invalid()

Am 28.04.2014 12:58, schrieb Dan Carpenter:
> The obd_ioctl_getdata() function caps "data->ioc_len" at
> OBD_MAX_IOCTL_BUFFER and then calls this obd_ioctl_is_invalid() to check
> that the other values inside data are valid.
>
> There are several lengths inside data but when they are added together
> they must not be larger than "data->ioc_len". The checks against
> "(data->ioc_inllen1 > (1<<30))" are supposed to ensure that the addition
> does not have an integer overflow. But "(1<<30) * 4" actually can
> overflow 32 bits, so the checks are insufficient.
>
> I have changed it to "> OBD_MAX_IOCTL_BUFFER" instead.
>
> Signed-off-by: Dan Carpenter <[email protected]>
> ---
> v2: Updated the error messages as Walter Harms pointed out.
>
> diff --git a/drivers/staging/lustre/lustre/include/lustre_lib.h b/drivers/staging/lustre/lustre/include/lustre_lib.h
> index bdc9812..3c26bbd 100644
> --- a/drivers/staging/lustre/lustre/include/lustre_lib.h
> +++ b/drivers/staging/lustre/lustre/include/lustre_lib.h
> @@ -179,24 +179,25 @@ static inline int obd_ioctl_packlen(struct obd_ioctl_data *data)
>
> static inline int obd_ioctl_is_invalid(struct obd_ioctl_data *data)
> {
> - if (data->ioc_len > (1<<30)) {
> - CERROR("OBD ioctl: ioc_len larger than 1<<30\n");
> + if (data->ioc_len > OBD_MAX_IOCTL_BUFFER) {
> + CERROR("OBD ioctl: ioc_len larger than %d\n",
> + OBD_MAX_IOCTL_BUFFER);
> return 1;
> }
> - if (data->ioc_inllen1 > (1<<30)) {
> - CERROR("OBD ioctl: ioc_inllen1 larger than 1<<30\n");
> + if (data->ioc_inllen1 > OBD_MAX_IOCTL_BUFFER) {
> + CERROR("OBD ioctl: ioc_inllen1 larger than ioc_len\n");
> return 1;
> }

The error mention ioc_len the compare is OBD_MAX_IOCTL_BUFFER ?
Is that intentional ?

re,
wh

> - if (data->ioc_inllen2 > (1<<30)) {
> - CERROR("OBD ioctl: ioc_inllen2 larger than 1<<30\n");
> + if (data->ioc_inllen2 > OBD_MAX_IOCTL_BUFFER) {
> + CERROR("OBD ioctl: ioc_inllen2 larger than ioc_len\n");
> return 1;
> }
> - if (data->ioc_inllen3 > (1<<30)) {
> - CERROR("OBD ioctl: ioc_inllen3 larger than 1<<30\n");
> + if (data->ioc_inllen3 > OBD_MAX_IOCTL_BUFFER) {
> + CERROR("OBD ioctl: ioc_inllen3 larger than ioc_len\n");
> return 1;
> }
> - if (data->ioc_inllen4 > (1<<30)) {
> - CERROR("OBD ioctl: ioc_inllen4 larger than 1<<30\n");
> + if (data->ioc_inllen4 > OBD_MAX_IOCTL_BUFFER) {
> + CERROR("OBD ioctl: ioc_inllen4 larger than ioc_len\n");
> return 1;
> }
> if (data->ioc_inlbuf1 && !data->ioc_inllen1) {
>

2014-04-28 11:41:52

by Dan Carpenter

Subject: Re: [patch 2/2 v2] staging: lustre: integer overflow in obd_ioctl_is_invalid()

On Mon, Apr 28, 2014 at 01:35:19PM +0200, walter harms wrote:
>
>
> Am 28.04.2014 12:58, schrieb Dan Carpenter:
> > The obd_ioctl_getdata() function caps "data->ioc_len" at
> > OBD_MAX_IOCTL_BUFFER and then calls this obd_ioctl_is_invalid() to check
> > that the other values inside data are valid.
> >
> > There are several lengths inside data but when they are added together
> > they must not be larger than "data->ioc_len". The checks against
> > "(data->ioc_inllen1 > (1<<30))" are supposed to ensure that the addition
> > does not have an integer overflow. But "(1<<30) * 4" actually can
> > overflow 32 bits, so the checks are insufficient.
> >
> > I have changed it to "> OBD_MAX_IOCTL_BUFFER" instead.
> >
> > Signed-off-by: Dan Carpenter <[email protected]>
> > ---
> > v2: Updated the error messages as Walter Harms pointed out.
> >
> > diff --git a/drivers/staging/lustre/lustre/include/lustre_lib.h b/drivers/staging/lustre/lustre/include/lustre_lib.h
> > index bdc9812..3c26bbd 100644
> > --- a/drivers/staging/lustre/lustre/include/lustre_lib.h
> > +++ b/drivers/staging/lustre/lustre/include/lustre_lib.h
> > @@ -179,24 +179,25 @@ static inline int obd_ioctl_packlen(struct obd_ioctl_data *data)
> >
> > static inline int obd_ioctl_is_invalid(struct obd_ioctl_data *data)
> > {
> > - if (data->ioc_len > (1<<30)) {
> > - CERROR("OBD ioctl: ioc_len larger than 1<<30\n");
> > + if (data->ioc_len > OBD_MAX_IOCTL_BUFFER) {
> > + CERROR("OBD ioctl: ioc_len larger than %d\n",
> > + OBD_MAX_IOCTL_BUFFER);
> > return 1;
> > }
> > - if (data->ioc_inllen1 > (1<<30)) {
> > - CERROR("OBD ioctl: ioc_inllen1 larger than 1<<30\n");
> > + if (data->ioc_inllen1 > OBD_MAX_IOCTL_BUFFER) {
> > + CERROR("OBD ioctl: ioc_inllen1 larger than ioc_len\n");
> > return 1;
> > }
>
> The error mention ioc_len the compare is OBD_MAX_IOCTL_BUFFER ?
> Is that intentional ?

Yep.

regards,
dan carpenter