On Tue, 2022-12-20 at 18:16 +1100, Andrew Donnellan wrote:
> From: Nayna Jain <na...@linux.ibm.com>
>
> The Platform Keystore provides a signed update interface which can be
> used
> to create, replace or append to certain variables in the PKS in a
> secure
> fashion, with the hypervisor requiring that the update be signed
> using the
> Platform Key.
>
> Implement an interface to the H_PKS_SIGNED_UPDATE hcall in the plpks
> driver to allow signed updates to PKS objects.
>
> (The plpks driver doesn't need to do any cryptography or otherwise
> handle
> the actual signed variable contents - that will be handled by
> userspace
> tooling.)
>
> Signed-off-by: Nayna Jain <na...@linux.ibm.com>
> [ajd: split patch, rewrite commit message, add timeout handling]
> Co-developed-by: Andrew Donnellan <a...@linux.ibm.com>
> Signed-off-by: Andrew Donnellan <a...@linux.ibm.com>
> ---
> arch/powerpc/include/asm/hvcall.h | 3 +-
> arch/powerpc/platforms/pseries/plpks.c | 81 +++++++++++++++++++++++-
> --
> arch/powerpc/platforms/pseries/plpks.h | 5 ++
> 3 files changed, 79 insertions(+), 10 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/hvcall.h
> b/arch/powerpc/include/asm/hvcall.h
> index 95fd7f9485d5..33b26c0cb69b 100644
> --- a/arch/powerpc/include/asm/hvcall.h
> +++ b/arch/powerpc/include/asm/hvcall.h
> @@ -336,7 +336,8 @@
> #define H_SCM_FLUSH 0x44C
> #define H_GET_ENERGY_SCALE_INFO 0x450
> #define H_WATCHDOG 0x45C
> -#define MAX_HCALL_OPCODE H_WATCHDOG
> +#define H_PKS_SIGNED_UPDATE 0x454
> +#define MAX_HCALL_OPCODE H_PKS_SIGNED_UPDATE
>
> /* Scope args for H_SCM_UNBIND_ALL */
> #define H_UNBIND_SCOPE_ALL (0x1)
> diff --git a/arch/powerpc/platforms/pseries/plpks.c
> b/arch/powerpc/platforms/pseries/plpks.c
> index c5ae00a8a968..9e4401aabf4f 100644
> --- a/arch/powerpc/platforms/pseries/plpks.c
> +++ b/arch/powerpc/platforms/pseries/plpks.c
> @@ -30,9 +30,9 @@
> #define MAX_NAME_SIZE 239
> #define MAX_DATA_SIZE 4000
>
> -#define PKS_FLUSH_MAX_TIMEOUT 5000 //msec
> -#define PKS_FLUSH_SLEEP 10 //msec
> -#define PKS_FLUSH_SLEEP_RANGE 400
> +#define PKS_MAX_TIMEOUT 5000 // msec
> +#define PKS_FLUSH_SLEEP 10 // msec
> +#define PKS_FLUSH_SLEEP_RANGE 400
>
> static u8 *ospassword;
> static u16 ospasswordlength;
> @@ -95,6 +95,12 @@ static int pseries_status_to_err(int rc)
> err = -ENOENT;
> break;
> case H_BUSY:
> + case H_LONG_BUSY_ORDER_1_MSEC:
> + case H_LONG_BUSY_ORDER_10_MSEC:
> + case H_LONG_BUSY_ORDER_100_MSEC:
> + case H_LONG_BUSY_ORDER_1_SEC:
> + case H_LONG_BUSY_ORDER_10_SEC:
> + case H_LONG_BUSY_ORDER_100_SEC:
> err = -EBUSY;
> break;
> case H_AUTHORITY:
> @@ -198,14 +204,17 @@ static struct label *construct_label(char
> *component, u8 varos, u8 *name,
> u16 namelen)
> {
> struct label *label;
> - size_t slen;
> + size_t slen = 0;
>
> if (!name || namelen > MAX_NAME_SIZE)
> return ERR_PTR(-EINVAL);
>
> - slen = strlen(component);
> - if (component && slen > sizeof(label->attr.prefix))
> - return ERR_PTR(-EINVAL);
> + // Support NULL component for signed updates
> + if (component) {
> + slen = strlen(component);
> + if (slen > sizeof(label->attr.prefix))
> + return ERR_PTR(-EINVAL);
> + }
>
> // The label structure must not cross a page boundary, so we
> align to the next power of 2
> label = kzalloc(roundup_pow_of_two(sizeof(*label)),
> GFP_KERNEL);
> @@ -372,7 +381,7 @@ static int plpks_confirm_object_flushed(struct
> label *label,
> usleep_range(PKS_FLUSH_SLEEP,
> PKS_FLUSH_SLEEP +
> PKS_FLUSH_SLEEP_RANGE);
> timeout = timeout + PKS_FLUSH_SLEEP;
> - } while (timeout < PKS_FLUSH_MAX_TIMEOUT);
> + } while (timeout < PKS_MAX_TIMEOUT);
>
> if (timed_out)
> rc = -ETIMEDOUT;
> @@ -382,6 +391,60 @@ static int plpks_confirm_object_flushed(struct
> label *label,
> return rc;
> }
>
> +int plpks_signed_update_var(struct plpks_var var, u64 flags)
> +{
> + unsigned long retbuf[PLPAR_HCALL9_BUFSIZE] = {0};
> + int rc;
> + struct label *label;
> + struct plpks_auth *auth;
> + u64 continuetoken = 0;
> + u64 timeout = 0;
> +
> + if (!var.data || var.datalen <= 0 || var.namelen >
> MAX_NAME_SIZE)
> + return -EINVAL;
> +
> + if (!(var.policy & SIGNEDUPDATE))
> + return -EINVAL;
> +
> + auth = construct_auth(PKS_OS_OWNER);
> + if (IS_ERR(auth))
> + return PTR_ERR(auth);
> +
> + label = construct_label(var.component, var.os, var.name,
> var.namelen);
> + if (IS_ERR(label)) {
> + rc = PTR_ERR(label);
> + goto out;
> + }
> +
> + do {
> + rc = plpar_hcall9(H_PKS_SIGNED_UPDATE, retbuf,
> + virt_to_phys(auth),
> virt_to_phys(label),
> + label->size, var.policy, flags,
> + virt_to_phys(var.data),
> var.datalen,
> + continuetoken);
> +
> + continuetoken = retbuf[0];
> + if (pseries_status_to_err(rc) == -EBUSY) {
> + int delay_ms = get_longbusy_msecs(rc);
> + mdelay(delay_ms);
> + timeout += delay_ms;
> + }
> + rc = pseries_status_to_err(rc);
> + } while (rc == -EBUSY && timeout < PKS_MAX_TIMEOUT);
> +
> + if (!rc) {
> + rc = plpks_confirm_object_flushed(label, auth);
> + rc = pseries_status_to_err(rc);
Doesn't plpks_confirm_object_flushed() already return a Linux-friendly
error code? If I'm reading this right, we'd be replacing any non-zero
return code with -EINVAL.
> + }
> +
> + kfree(label);
> +out:
> + kfree(auth);
> +
> + return rc;
> +}
> +EXPORT_SYMBOL(plpks_signed_update_var);
> +
> int plpks_write_var(struct plpks_var var)
> {
> unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
> @@ -428,7 +491,7 @@ int plpks_remove_var(char *component, u8 varos,
> struct plpks_var_name vname)
> struct label *label;
> int rc;
>
> - if (!component || vname.namelen > MAX_NAME_SIZE)
> + if (vname.namelen > MAX_NAME_SIZE)
> return -EINVAL;
>
> auth = construct_auth(PKS_OS_OWNER);
> diff --git a/arch/powerpc/platforms/pseries/plpks.h
> b/arch/powerpc/platforms/pseries/plpks.h
> index c89740796660..33cf12809392 100644
> --- a/arch/powerpc/platforms/pseries/plpks.h
> +++ b/arch/powerpc/platforms/pseries/plpks.h
> @@ -40,6 +40,11 @@ struct plpks_var_name_list {
> struct plpks_var_name varlist[];
> };
>
> +/**
> + * Updates the authenticated variable. It expects NULL as the
> component.
> + */
> +int plpks_signed_update_var(struct plpks_var var, u64 flags);
> +
> /**
> * Writes the specified var and its data to PKS.
> * Any caller of PKS driver should present a valid component type
> for
