From 899d9b8fee66da820eadc60b2a70090eb83db761 Mon Sep 17 00:00:00 2001 From: Nayna Jain Date: Fri, 10 Feb 2023 19:03:52 +1100 Subject: [PATCH] powerpc/pseries: Implement signed update for PLPKS objects 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 [ajd: split patch, add timeout handling and misc cleanups] Co-developed-by: Andrew Donnellan Signed-off-by: Andrew Donnellan Signed-off-by: Russell Currey Reviewed-by: Stefan Berger Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20230210080401.345462-18-ajd@linux.ibm.com --- arch/powerpc/include/asm/hvcall.h | 1 + arch/powerpc/include/asm/plpks.h | 5 +++ arch/powerpc/platforms/pseries/plpks.c | 74 +++++++++++++++++++++++++++++++--- 3 files changed, 75 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h index 95fd7f9..c099780 100644 --- a/arch/powerpc/include/asm/hvcall.h +++ b/arch/powerpc/include/asm/hvcall.h @@ -335,6 +335,7 @@ #define H_RPT_INVALIDATE 0x448 #define H_SCM_FLUSH 0x44C #define H_GET_ENERGY_SCALE_INFO 0x450 +#define H_PKS_SIGNED_UPDATE 0x454 #define H_WATCHDOG 0x45C #define MAX_HCALL_OPCODE H_WATCHDOG diff --git a/arch/powerpc/include/asm/plpks.h b/arch/powerpc/include/asm/plpks.h index 7c5f51a..e7204e6 100644 --- a/arch/powerpc/include/asm/plpks.h +++ b/arch/powerpc/include/asm/plpks.h @@ -69,6 +69,11 @@ struct plpks_var_name_list { }; /** + * 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 * their variable. diff --git a/arch/powerpc/platforms/pseries/plpks.c b/arch/powerpc/platforms/pseries/plpks.c index 1189246..cee06fb 100644 --- a/arch/powerpc/platforms/pseries/plpks.c +++ b/arch/powerpc/platforms/pseries/plpks.c @@ -81,6 +81,12 @@ 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: @@ -184,14 +190,17 @@ 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 > PLPKS_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); @@ -397,6 +406,61 @@ static int plpks_confirm_object_flushed(struct label *label, return pseries_status_to_err(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 > PLPKS_MAX_NAME_SIZE) + return -EINVAL; + + if (!(var->policy & PLPKS_SIGNEDUPDATE)) + return -EINVAL; + + // Signed updates need the component to be NULL. + if (var->component) + return -EINVAL; + + auth = construct_auth(PLPKS_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 < PLPKS_MAX_TIMEOUT); + + if (!rc) + rc = plpks_confirm_object_flushed(label, auth); + + kfree(label); +out: + kfree(auth); + + return rc; +} + int plpks_write_var(struct plpks_var var) { unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 }; @@ -443,7 +507,7 @@ int plpks_remove_var(char *component, u8 varos, struct plpks_var_name vname) struct label *label; int rc; - if (!component || vname.namelen > PLPKS_MAX_NAME_SIZE) + if (vname.namelen > PLPKS_MAX_NAME_SIZE) return -EINVAL; auth = construct_auth(PLPKS_OS_OWNER); -- 2.7.4