| Message ID | 1493909787-1848-2-git-send-email-stefanb@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, May 04, 2017 at 10:56:25AM -0400, Stefan Berger wrote: > Implement VTPM_PROXY_IOC_GET_SUPT_FLAGS ioctl to get the bitmask > of flags that the vtpm_proxy driver supports in the > VTPM_PROXY_IOC_NEW_DEV ioctl. This helps user space in deciding > which flags to set in that ioctl. you might be better off just having a VTPM_PROXY_IO_ENABLE_FEATURE .feature = LOCALITY If that fails then the feature is not supported, no real need for the query in that case. Not sure about Jarkko's point on request/release locality.. Is there a scenario where the emulator should fail the request locality? Jason -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 05/04/2017 11:34 AM, Jason Gunthorpe wrote: > On Thu, May 04, 2017 at 10:56:25AM -0400, Stefan Berger wrote: >> Implement VTPM_PROXY_IOC_GET_SUPT_FLAGS ioctl to get the bitmask >> of flags that the vtpm_proxy driver supports in the >> VTPM_PROXY_IOC_NEW_DEV ioctl. This helps user space in deciding >> which flags to set in that ioctl. > you might be better off just having a VTPM_PROXY_IO_ENABLE_FEATURE > .feature = LOCALITY Do you have an example driver that shows how to do this ? Can user space query that feature? > > If that fails then the feature is not supported, no real need for the > query in that case. > > Not sure about Jarkko's point on request/release locality.. Is there a > scenario where the emulator should fail the request locality? We could filter localities 5 and higher on the level of the driver (patch 2/3) since basically there are only 5 localities (0-4) in any TPM interface today. The typical hardware locality 4 would be filtered by the emulator per policy passed via command line, but I would allow it on the level of this driver. An error message would be returned for any command executed in that locality, unless the 'policy' allows it. Localities 0-3 should just be selectable. The TPM TIS (in the hardware) implements some complicated scheme when it comes to allowing the selection of a locality and I would say we need none of that but just tell the vTPM proxy driver the locality (patch 2/3) in which the next command will be executed. > > Jason > -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, May 04, 2017 at 01:13:18PM -0400, Stefan Berger wrote: > On 05/04/2017 11:34 AM, Jason Gunthorpe wrote: > >On Thu, May 04, 2017 at 10:56:25AM -0400, Stefan Berger wrote: > >>Implement VTPM_PROXY_IOC_GET_SUPT_FLAGS ioctl to get the bitmask > >>of flags that the vtpm_proxy driver supports in the > >>VTPM_PROXY_IOC_NEW_DEV ioctl. This helps user space in deciding > >>which flags to set in that ioctl. > >you might be better off just having a VTPM_PROXY_IO_ENABLE_FEATURE > >.feature = LOCALITY > > Do you have an example driver that shows how to do this ? Can user space > query that feature? Try and enable the feature, if it fails then there is no feature in the kernel. This is the usual way to add new syscalls.. > >If that fails then the feature is not supported, no real need for the > >query in that case. > > > >Not sure about Jarkko's point on request/release locality.. Is there a > >scenario where the emulator should fail the request locality? > > We could filter localities 5 and higher on the level of the driver (patch > 2/3) since basically there are only 5 localities (0-4) in any TPM interface > today. The typical hardware locality 4 would be filtered by the emulator per > policy passed via command line, but I would allow it on the level of this > driver. An error message would be returned for any command executed in that > locality, unless the 'policy' allows it. Localities 0-3 should just be > selectable. The TPM TIS (in the hardware) implements some complicated scheme > when it comes to allowing the selection of a locality and I would say we > need none of that but just tell the vTPM proxy driver the locality (patch > 2/3) in which the next command will be executed. Well, if TIS hardware has some scheme I feel like the emulator uAPI should have enough fidelity to ecompass existing hardware, even if your current emulator does not need it. So allowing request_locality to fail from userspace seems reasonable. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 05/04/2017 01:20 PM, Jason Gunthorpe wrote: > On Thu, May 04, 2017 at 01:13:18PM -0400, Stefan Berger wrote: >> On 05/04/2017 11:34 AM, Jason Gunthorpe wrote: >>> On Thu, May 04, 2017 at 10:56:25AM -0400, Stefan Berger wrote: >>>> Implement VTPM_PROXY_IOC_GET_SUPT_FLAGS ioctl to get the bitmask >>>> of flags that the vtpm_proxy driver supports in the >>>> VTPM_PROXY_IOC_NEW_DEV ioctl. This helps user space in deciding >>>> which flags to set in that ioctl. >>> you might be better off just having a VTPM_PROXY_IO_ENABLE_FEATURE >>> .feature = LOCALITY >> Do you have an example driver that shows how to do this ? Can user space >> query that feature? > Try and enable the feature, if it fails then there is no feature in > the kernel. > > This is the usual way to add new syscalls.. > >>> If that fails then the feature is not supported, no real need for the >>> query in that case. >>> >>> Not sure about Jarkko's point on request/release locality.. Is there a >>> scenario where the emulator should fail the request locality? >> We could filter localities 5 and higher on the level of the driver (patch >> 2/3) since basically there are only 5 localities (0-4) in any TPM interface >> today. The typical hardware locality 4 would be filtered by the emulator per >> policy passed via command line, but I would allow it on the level of this >> driver. An error message would be returned for any command executed in that >> locality, unless the 'policy' allows it. Localities 0-3 should just be >> selectable. The TPM TIS (in the hardware) implements some complicated scheme >> when it comes to allowing the selection of a locality and I would say we >> need none of that but just tell the vTPM proxy driver the locality (patch >> 2/3) in which the next command will be executed. > Well, if TIS hardware has some scheme I feel like the emulator uAPI should > have enough fidelity to ecompass existing hardware, even if your > current emulator does not need it. > > So allowing request_locality to fail from userspace seems reasonable. What's the best interface to use for this ? -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, May 04, 2017 at 01:28:17PM -0400, Stefan Berger wrote: > >So allowing request_locality to fail from userspace seems reasonable. > > What's the best interface to use for this ? If locality support is enabled then send a request locality packet to userspace and block until return, just like command execution? Jason -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 05/04/2017 01:31 PM, Jason Gunthorpe wrote: > On Thu, May 04, 2017 at 01:28:17PM -0400, Stefan Berger wrote: > >>> So allowing request_locality to fail from userspace seems reasonable. >> What's the best interface to use for this ? > If locality support is enabled then send a request locality packet to > userspace and block until return, just like command execution? We would have to invent a command for that... -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c index 751059d..fb4d207 100644 --- a/drivers/char/tpm/tpm_vtpm_proxy.c +++ b/drivers/char/tpm/tpm_vtpm_proxy.c @@ -592,6 +592,33 @@ static long vtpmx_ioc_new_dev(struct file *file, unsigned int ioctl, return 0; } +/** + * vtpmx_ioc_get_supt_flags - handler for the %VTPM_PROXY_IOC_GET_SUPT_FLAGS + * ioctl + * @file: /dev/vtpmx + * @ioctl: the ioctl number + * @arg: pointer to the struct vtpmx_proxy_get_supt_flags + * + * Return the bitfield of supported flags + */ +static long vtpmx_ioc_get_supt_flags(struct file *file, unsigned int ioctl, + unsigned long arg) +{ + void __user *argp = (void __user *)arg; + struct vtpm_proxy_supt_flags __user *vtpm_supt_flags_p = argp; + struct vtpm_proxy_supt_flags flags = { + .flags = VTPM_PROXY_FLAGS_ALL, + }; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (copy_to_user(vtpm_supt_flags_p, &flags, sizeof(flags))) + return -EFAULT; + + return 0; +} + /* * vtpmx_fops_ioctl: ioctl on /dev/vtpmx * @@ -604,6 +631,8 @@ static long vtpmx_fops_ioctl(struct file *f, unsigned int ioctl, switch (ioctl) { case VTPM_PROXY_IOC_NEW_DEV: return vtpmx_ioc_new_dev(f, ioctl, arg); + case VTPM_PROXY_IOC_GET_SUPT_FLAGS: + return vtpmx_ioc_get_supt_flags(f, ioctl, arg); default: return -ENOIOCTLCMD; } diff --git a/include/uapi/linux/vtpm_proxy.h b/include/uapi/linux/vtpm_proxy.h index a69e991..83e64e7 100644 --- a/include/uapi/linux/vtpm_proxy.h +++ b/include/uapi/linux/vtpm_proxy.h @@ -44,6 +44,17 @@ struct vtpm_proxy_new_dev { __u32 minor; /* output */ }; +/** + * struct vtpm_proxy_supt_flags - parameter structure for the + * %VTPM_PROXY_IOC_GET_SUPT_FLAGS ioctl + * @flags: flags supported by the vtpm proxy driver + */ +struct vtpm_proxy_supt_flags { + __u32 flags; /* output */ +}; + #define VTPM_PROXY_IOC_NEW_DEV _IOWR(0xa1, 0x00, struct vtpm_proxy_new_dev) +#define VTPM_PROXY_IOC_GET_SUPT_FLAGS \ + _IOR(0xa1, 0x01, struct vtpm_proxy_supt_flags) #endif /* _UAPI_LINUX_VTPM_PROXY_H */
Implement VTPM_PROXY_IOC_GET_SUPT_FLAGS ioctl to get the bitmask of flags that the vtpm_proxy driver supports in the VTPM_PROXY_IOC_NEW_DEV ioctl. This helps user space in deciding which flags to set in that ioctl. Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> --- drivers/char/tpm/tpm_vtpm_proxy.c | 29 +++++++++++++++++++++++++++++ include/uapi/linux/vtpm_proxy.h | 11 +++++++++++ 2 files changed, 40 insertions(+)