The hypervisor generated wrapping key is an AES-GCM-256 symmetric key which is stored in a non-volatile, secure, and encrypted storage called the Power LPAR Platform KeyStore. It has policy based protections that prevent it from being read out or exposed to the user.
Implement H_PKS_GEN_KEY, H_PKS_WRAP_OBJECT, and H_PKS_UNWRAP_OBJECT HCALLs to enable using the PowerVM Key Wrapping Module (PKWM) as a new trust source for trusted keys. Disallow H_PKS_READ_OBJECT, H_PKS_SIGNED_UPDATE, and H_PKS_WRITE_OBJECT for objects with the 'wrapping key' policy set. Capture the availability status for the H_PKS_WRAP_OBJECT interface. Signed-off-by: Srish Srinivasan <[email protected]> --- Documentation/arch/powerpc/papr_hcalls.rst | 43 +++ arch/powerpc/include/asm/plpks.h | 10 + arch/powerpc/platforms/pseries/plpks.c | 345 ++++++++++++++++++++- 3 files changed, 396 insertions(+), 2 deletions(-) diff --git a/Documentation/arch/powerpc/papr_hcalls.rst b/Documentation/arch/powerpc/papr_hcalls.rst index 805e1cb9bab9..14e39f095a1c 100644 --- a/Documentation/arch/powerpc/papr_hcalls.rst +++ b/Documentation/arch/powerpc/papr_hcalls.rst @@ -300,6 +300,49 @@ H_HTM supports setup, configuration, control and dumping of Hardware Trace Macro (HTM) function and its data. HTM buffer stores tracing data for functions like core instruction, core LLAT and nest. +**H_PKS_GEN_KEY** + +| Input: authorization, objectlabel, objectlabellen, policy, out, outlen +| Out: *Hypervisor Generated Key, or None when the wrapping key policy is set* +| Return Value: *H_SUCCESS, H_Function, H_State, H_R_State, H_Parameter, H_P2, + H_P3, H_P4, H_P5, H_P6, H_Authority, H_Nomem, H_Busy, H_Resource, + H_Aborted* + +H_PKS_GEN_KEY is used to have the hypervisor generate a new random key. +This key is stored as an object in the Power LPAR Platform KeyStore with +the provided object label. With the wrapping key policy set the key is only +visible to the hypervisor, while the key's label would still be visible to +the user. Generation of wrapping keys is supported only for a key size of +32 bytes. + +**H_PKS_WRAP_OBJECT** + +| Input: authorization, wrapkeylabel, wrapkeylabellen, objectwrapflags, in, +| inlen, out, outlen, continue-token +| Out: *continue-token, byte size of wrapped object, wrapped object* +| Return Value: *H_SUCCESS, H_Function, H_State, H_R_State, H_Parameter, H_P2, + H_P3, H_P4, H_P5, H_P6, H_P7, H_P8, H_P9, H_Authority, H_Invalid_Key, + H_NOT_FOUND, H_Busy, H_LongBusy, H_Aborted* + +H_PKS_WRAP_OBJECT is used to wrap an object using a wrapping key stored in the +Power LPAR Platform KeyStore and return the wrapped object to the caller. The +caller provides a label to a wrapping key with the 'wrapping key' policy set, +which must have been previously created with H_PKS_GEN_KEY. The provided object +is then encrypted with the wrapping key and additional metadata and the result +is returned to the caller. + + +**H_PKS_UNWRAP_OBJECT** + +| Input: authorization, objectwrapflags, in, inlen, out, outlen, continue-token +| Out: *continue-token, byte size of unwrapped object, unwrapped object* +| Return Value: *H_SUCCESS, H_Function, H_State, H_R_State, H_Parameter, H_P2, + H_P3, H_P4, H_P5, H_P6, H_P7, H_Authority, H_Unsupported, H_Bad_Data, + H_NOT_FOUND, H_Invalid_Key, H_Busy, H_LongBusy, H_Aborted* + +H_PKS_UNWRAP_OBJECT is used to unwrap an object that was previously warapped with +H_PKS_WRAP_OBJECT. + References ========== .. [1] "Power Architecture Platform Reference" diff --git a/arch/powerpc/include/asm/plpks.h b/arch/powerpc/include/asm/plpks.h index 8c20fd5a8fd4..42ef23519956 100644 --- a/arch/powerpc/include/asm/plpks.h +++ b/arch/powerpc/include/asm/plpks.h @@ -113,6 +113,16 @@ void plpks_early_init_devtree(void); int plpks_populate_fdt(void *fdt); int plpks_config_create_softlink(struct kobject *from); + +bool plpks_wrapping_is_supported(void); + +int plpks_gen_wrapping_key(void); + +int plpks_wrap_object(u8 **input_buf, u32 input_len, u16 wrap_flags, + u8 **output_buf, u32 *output_len); + +int plpks_unwrap_object(u8 **input_buf, u32 input_len, + u8 **output_buf, u32 *output_len); #else // CONFIG_PSERIES_PLPKS static inline bool plpks_is_available(void) { return false; } static inline u16 plpks_get_passwordlen(void) { BUILD_BUG(); } diff --git a/arch/powerpc/platforms/pseries/plpks.c b/arch/powerpc/platforms/pseries/plpks.c index 4a08f51537c8..2ec04908b057 100644 --- a/arch/powerpc/platforms/pseries/plpks.c +++ b/arch/powerpc/platforms/pseries/plpks.c @@ -9,6 +9,32 @@ #define pr_fmt(fmt) "plpks: " fmt +#define PLPKS_WRAPKEY_COMPONENT "PLPKSWR" +#define PLPKS_WRAPKEY_NAME "default-wrapping-key" + +/* + * To 4K align the {input, output} buffers to the {UN}WRAP H_CALLs + */ +#define PLPKS_WRAPPING_BUF_ALIGN 4096 + +/* + * To ensure the output buffer's length is at least 1024 bytes greater + * than the input buffer's length during the WRAP H_CALL + */ +#define PLPKS_WRAPPING_BUF_DIFF 1024 + +#define PLPKS_WRAP_INTERFACE_BIT 3 +#define PLPKS_WRAPPING_KEY_LENGTH 32 + +#define WRAPFLAG_BE_BIT_SET(be_bit) \ + BIT_ULL(63 - (be_bit)) + +#define WRAPFLAG_BE_GENMASK(be_bit_hi, be_bit_lo) \ + GENMASK_ULL(63 - (be_bit_hi), 63 - (be_bit_lo)) + +#define WRAPFLAG_BE_FIELD_PREP(be_bit_hi, be_bit_lo, val) \ + FIELD_PREP(WRAPFLAG_BE_GENMASK(be_bit_hi, be_bit_lo), (val)) + #include <linux/delay.h> #include <linux/errno.h> #include <linux/io.h> @@ -39,6 +65,7 @@ static u32 supportedpolicies; static u32 maxlargeobjectsize; static u64 signedupdatealgorithms; static u64 wrappingfeatures; +static bool wrapsupport; struct plpks_auth { u8 version; @@ -283,6 +310,7 @@ static int _plpks_get_config(void) maxlargeobjectsize = be32_to_cpu(config->maxlargeobjectsize); signedupdatealgorithms = be64_to_cpu(config->signedupdatealgorithms); wrappingfeatures = be64_to_cpu(config->wrappingfeatures); + wrapsupport = config->flags & PPC_BIT8(PLPKS_WRAP_INTERFACE_BIT); // Validate that the numbers we get back match the requirements of the spec if (maxpwsize < 32) { @@ -614,6 +642,9 @@ int plpks_signed_update_var(struct plpks_var *var, u64 flags) if (!(var->policy & PLPKS_SIGNEDUPDATE)) return -EINVAL; + if (var->policy & PLPKS_WRAPPINGKEY) + return -EINVAL; + // Signed updates need the component to be NULL. if (var->component) return -EINVAL; @@ -696,6 +727,9 @@ int plpks_write_var(struct plpks_var var) if (var.policy & PLPKS_SIGNEDUPDATE) return -EINVAL; + if (var.policy & PLPKS_WRAPPINGKEY) + return -EINVAL; + auth = construct_auth(PLPKS_OS_OWNER); if (IS_ERR(auth)) return PTR_ERR(auth); @@ -790,6 +824,9 @@ static int plpks_read_var(u8 consumer, struct plpks_var *var) if (var->namelen > PLPKS_MAX_NAME_SIZE) return -EINVAL; + if (var->policy & PLPKS_WRAPPINGKEY) + return -EINVAL; + auth = construct_auth(consumer); if (IS_ERR(auth)) return PTR_ERR(auth); @@ -845,8 +882,312 @@ static int plpks_read_var(u8 consumer, struct plpks_var *var) } /** - * plpks_read_os_var() - Fetch the data for the specified variable that is - * owned by the OS consumer. + * plpks_wrapping_is_supported() - Get the H_PKS_WRAP_OBJECT interface + * availability status for the LPAR. + * + * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization + * sets bit 3 of the flags variable in the PLPKS config structure if the + * H_PKS_WRAP_OBJECT interface is supported. + * + * Returns: true if the H_PKS_WRAP_OBJECT interface is supported, false if not. + */ +bool plpks_wrapping_is_supported(void) +{ + return wrapsupport; +} + +/** + * plpks_gen_wrapping_key() - Generate a new random key with the 'wrapping key' + * policy set. + * + * The H_PKS_GEN_KEY HCALL makes the hypervisor generate a new random key and + * store the key in a PLPKS object with the provided object label. With the + * 'wrapping key' policy set, only the label to the newly generated random key + * would be visible to the user. + * + * Possible reasons for the returned errno values: + * + * -ENXIO if PLPKS is not supported + * -EIO if PLPKS access is blocked due to the LPAR's state + * if PLPKS modification is blocked due to the LPAR's state + * if an error occurred while processing the request + * -EINVAL if invalid authorization parameter + * if invalid object label parameter + * if invalid object label len parameter + * if invalid or unsupported policy declaration + * if invalid output buffer parameter + * if invalid output buffer length parameter + * -EPERM if access is denied + * -ENOMEM if there is inadequate memory to perform this operation + * -EBUSY if unable to handle the request + * -EEXIST if the object label already exists + * + * Returns: On success 0 is returned, a negative errno if not. + */ +int plpks_gen_wrapping_key(void) +{ + unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 }; + struct plpks_auth *auth; + struct label *label; + int rc = 0, pseries_status = 0; + struct plpks_var var = { + .name = PLPKS_WRAPKEY_NAME, + .namelen = strlen(var.name), + .policy = PLPKS_WRAPPINGKEY, + .os = PLPKS_VAR_LINUX, + .component = PLPKS_WRAPKEY_COMPONENT + }; + + 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; + } + + rc = plpar_hcall(H_PKS_GEN_KEY, retbuf, + virt_to_phys(auth), virt_to_phys(label), + label->size, var.policy, + NULL, PLPKS_WRAPPING_KEY_LENGTH); + + if (!rc) + rc = plpks_confirm_object_flushed(label, auth); + + pseries_status = rc; + rc = pseries_status_to_err(rc); + + if (rc && rc != -EEXIST) { + pr_err("H_PKS_GEN_KEY failed."); + pr_err("pseries_status = %d, error code = %d", pseries_status, + rc); + } else { + rc = 0; + } + + kfree(label); +out: + kfree(auth); + return rc; +} +EXPORT_SYMBOL_GPL(plpks_gen_wrapping_key); + +/** + * plpks_wrap_object() - Wrap an object using the default wrapping key stored in + * the PLPKS. + * @input_buf: buffer containing the data to be wrapped + * @input_len: length of the input buffer + * @wrap_flags: object wrapping flags + * @output_buf: buffer to store the wrapped data + * @output_len: length of the output buffer + * + * The H_PKS_WRAP_OBJECT HCALL wraps an object using a wrapping key stored in + * the PLPKS and returns the wrapped object to the caller. The caller provides a + * label to the wrapping key with the 'wrapping key' policy set that must have + * been previously created with the H_PKS_GEN_KEY HCALL. The provided object is + * then encrypted with the wrapping key and additional metadata and the result + * is returned to the user. The metadata includes the wrapping algorithm and the + * wrapping key name so those parameters are not required during unwrap. + * + * Possible reasons for the returned errno values: + * + * -ENXIO if PLPKS is not supported + * -EIO if PLPKS access is blocked due to the LPAR's state + * if PLPKS modification is blocked due to the LPAR's state + * if an error occurred while processing the request + * -EINVAL if invalid authorization parameter + * if invalid wraping key label parameter + * if invalid wrapping key label length parameter + * if invalid or unsupported object wrapping flags + * if invalid inut buffer parameter + * if invalid input buffer length parameter + * if invalid output buffer parameter + * if invalid output buffer length parameter + * if invalid continue token parameter + * if the wrapping key is not compatible with the wrapping + * algorithm + * -EPERM if access is denied + * -ENOENT if the requested wrapping key was not found + * -EBUSY if unable to handle the request or long running operation + * initiated, retry later. + * + * Returns: On success 0 is returned, a negative errno if not. + */ +int plpks_wrap_object(u8 **input_buf, u32 input_len, u16 wrap_flags, + u8 **output_buf, u32 *output_len) +{ + unsigned long retbuf[PLPAR_HCALL9_BUFSIZE] = { 0 }; + struct plpks_auth *auth; + struct label *label; + u64 continuetoken = 0; + u64 objwrapflags = 0; + int rc = 0, pseries_status = 0; + bool sb_audit_or_enforce_bit = wrap_flags & BIT(0); + bool sb_enforce_bit = wrap_flags & BIT(1); + struct plpks_var var = { + .name = PLPKS_WRAPKEY_NAME, + .namelen = strlen(var.name), + .os = PLPKS_VAR_LINUX, + .component = PLPKS_WRAPKEY_COMPONENT + }; + + 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; + } + + /* Set the consumer password requirement bit. A must have. */ + objwrapflags |= WRAPFLAG_BE_BIT_SET(3); + + /* Set the wrapping algorithm bit. Just one algorithm option for now */ + objwrapflags |= WRAPFLAG_BE_FIELD_PREP(60, 63, 0x1); + + if (sb_audit_or_enforce_bit & sb_enforce_bit) { + pr_err("Cannot set both audit/enforce and enforce bits."); + rc = -EINVAL; + goto out_free_label; + } else if (sb_audit_or_enforce_bit) { + objwrapflags |= WRAPFLAG_BE_BIT_SET(1); + } else if (sb_enforce_bit) { + objwrapflags |= WRAPFLAG_BE_BIT_SET(2); + } + + *output_len = input_len + PLPKS_WRAPPING_BUF_DIFF; + + *output_buf = kzalloc(ALIGN(*output_len, PLPKS_WRAPPING_BUF_ALIGN), + GFP_KERNEL); + if (!(*output_buf)) { + pr_err("Output buffer allocation failed. Returning -ENOMEM."); + rc = -ENOMEM; + goto out_free_label; + } + + do { + rc = plpar_hcall9(H_PKS_WRAP_OBJECT, retbuf, + virt_to_phys(auth), virt_to_phys(label), + label->size, objwrapflags, + virt_to_phys(*input_buf), input_len, + virt_to_phys(*output_buf), *output_len, + continuetoken); + + continuetoken = retbuf[0]; + pseries_status = rc; + rc = pseries_status_to_err(rc); + } while (rc == -EBUSY); + + if (rc) { + pr_err("H_PKS_WRAP_OBJECT failed."); + pr_err("pseries_status = %d, return code = %d", pseries_status, + rc); + kfree(*output_buf); + *output_buf = NULL; + } else { + *output_len = retbuf[1]; + } + +out_free_label: + kfree(label); +out: + kfree(auth); + return rc; +} +EXPORT_SYMBOL_GPL(plpks_wrap_object); + +/** + * plpks_unwrap_object() - Unwrap an object using the default wrapping key + * stored in the PLPKS. + * @input_buf: buffer containing the data to be unwrapped + * @input_len: length of the input buffer + * @output_buf: buffer to store the unwrapped data + * @output_len: length of the output buffer + * + * The H_PKS_UNWRAP_OBJECT HCALL unwraps an object that was previously wrapped + * using the H_PKS_WRAP_OBJECT HCALL. + * + * Possible reasons for the returned errno values: + * + * -ENXIO if PLPKS is not supported + * -EIO if PLPKS access is blocked due to the LPAR's state + * if PLPKS modification is blocked due to the LPAR's state + * if an error occurred while processing the request + * -EINVAL if invalid authorization parameter + * if invalid or unsupported object unwrapping flags + * if invalid inut buffer parameter + * if invalid input buffer length parameter + * if invalid output buffer parameter + * if invalid output buffer length parameter + * if invalid continue token parameter + * if the wrapping key is not compatible with the wrapping + * algorithm + * if the wrapped object's format is not supported + * if the wrapped object is invalid + * -EPERM if access is denied + * -ENOENT if the wrapping key for the provided object was not found + * -EBUSY if unable to handle the request or long running operation + * initiated, retry later. + * + * Returns: On success 0 is returned, a negative errno if not. + */ +int plpks_unwrap_object(u8 **input_buf, u32 input_len, u8 **output_buf, + u32 *output_len) +{ + unsigned long retbuf[PLPAR_HCALL9_BUFSIZE] = { 0 }; + struct plpks_auth *auth; + u64 continuetoken = 0; + u64 objwrapflags = 0; + int rc = 0, pseries_status = 0; + + auth = construct_auth(PLPKS_OS_OWNER); + if (IS_ERR(auth)) + return PTR_ERR(auth); + + *output_len = input_len - PLPKS_WRAPPING_BUF_DIFF; + *output_buf = kzalloc(ALIGN(*output_len, PLPKS_WRAPPING_BUF_ALIGN), + GFP_KERNEL); + if (!(*output_buf)) { + pr_err("Output buffer allocation failed. Returning -ENOMEM."); + rc = -ENOMEM; + goto out; + } + + do { + rc = plpar_hcall9(H_PKS_UNWRAP_OBJECT, retbuf, + virt_to_phys(auth), objwrapflags, + virt_to_phys(*input_buf), input_len, + virt_to_phys(*output_buf), *output_len, + continuetoken); + + continuetoken = retbuf[0]; + pseries_status = rc; + rc = pseries_status_to_err(rc); + } while (rc == -EBUSY); + + if (rc) { + pr_err("H_PKS_UNWRAP_OBJECT failed."); + pr_err("pseries_status = %d, return code = %d", pseries_status, + rc); + kfree(*output_buf); + *output_buf = NULL; + } else { + *output_len = retbuf[1]; + } + +out: + kfree(auth); + return rc; +} +EXPORT_SYMBOL_GPL(plpks_unwrap_object); + +/** + * plpks_read_os_var() - Fetch the data for the specified variable that is owned + * by the OS consumer. * @var: variable to be read from the PLPKS * * The consumer or the owner of the object is the os kernel. The -- 2.47.3
