| Message ID | 20230719170423.220033-8-quic_gaurkash@quicinc.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | Hardware wrapped key support for qcom ice and ufs | expand |
On 7/19/2023 10:04 AM, Gaurav Kashyap wrote: > Storage encryption has two IOCTLs for creating, importing > and preparing keys for encryption. For wrapped keys, these > IOCTLs need to interface with the secure environment, which > require these SCM calls. > > generate_key: This is used to generate and return a longterm > wrapped key. Trustzone achieves this by generating > a key and then wrapping it using hwkm, returning > a wrapped keyblob. > import_key: The functionality is similar to generate, but here, > a raw key is imported into hwkm and a longterm wrapped > keyblob is returned. > prepare_key: The longterm wrapped key from import or generate > is made further secure by rewrapping it with a per-boot > ephemeral wrapped key before installing it to the linux > kernel for programming to ICE. > > Signed-off-by: Gaurav Kashyap <quic_gaurkash@quicinc.com> > --- > drivers/firmware/qcom_scm.c | 222 +++++++++++++++++++++++++ > drivers/firmware/qcom_scm.h | 3 + > include/linux/firmware/qcom/qcom_scm.h | 10 ++ > 3 files changed, 235 insertions(+) > > diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c > index 51062d5c7f7b..44dd1857747b 100644 > --- a/drivers/firmware/qcom_scm.c > +++ b/drivers/firmware/qcom_scm.c > @@ -1210,6 +1210,228 @@ int qcom_scm_derive_sw_secret(const u8 *wrapped_key, u32 wrapped_key_size, > } > EXPORT_SYMBOL(qcom_scm_derive_sw_secret); > > +/** > + * qcom_scm_generate_ice_key() - Generate a wrapped key for encryption. > + * @longterm_wrapped_key: the wrapped key returned after key generation > + * @longterm_wrapped_key_size: size of the wrapped key to be returned. > + * > + * Qualcomm wrapped keys need to be generated in a trusted environment. > + * A generate key IOCTL call is used to achieve this. These are longterm > + * in nature as they need to be generated and wrapped only once per > + * requirement. > + * > + * This SCM calls adds support for the generate key IOCTL to interface > + * with the secure environment to generate and return a wrapped key.. > + * > + * Return: 0 on success; -errno on failure. > + */ > +int qcom_scm_generate_ice_key(u8 *longterm_wrapped_key, > + u32 longterm_wrapped_key_size) > +{ > + struct qcom_scm_desc desc = { > + .svc = QCOM_SCM_SVC_ES, > + .cmd = QCOM_SCM_ES_GENERATE_ICE_KEY, > + .arginfo = QCOM_SCM_ARGS(2, QCOM_SCM_RW, > + QCOM_SCM_VAL), > + .args[1] = longterm_wrapped_key_size, > + .owner = ARM_SMCCC_OWNER_SIP, > + }; > + > + void *longterm_wrapped_keybuf; > + dma_addr_t longterm_wrapped_key_phys; > + int ret; > + > + /* > + * Like qcom_scm_ice_set_key(), we use dma_alloc_coherent() to properly > + * get a physical address, while guaranteeing that we can zeroize the > + * key material later using memzero_explicit(). > + * > + */ > + longterm_wrapped_keybuf = dma_alloc_coherent(__scm->dev, > + longterm_wrapped_key_size, > + &longterm_wrapped_key_phys, GFP_KERNEL); > + if (!longterm_wrapped_keybuf) > + return -ENOMEM; > + > + desc.args[0] = longterm_wrapped_key_phys; > + > + ret = qcom_scm_call(__scm->dev, &desc, NULL); > + memcpy(longterm_wrapped_key, longterm_wrapped_keybuf, > + longterm_wrapped_key_size); > + > + memzero_explicit(longterm_wrapped_keybuf, longterm_wrapped_key_size); > + dma_free_coherent(__scm->dev, longterm_wrapped_key_size, > + longterm_wrapped_keybuf, longterm_wrapped_key_phys); > + > + if (!ret) > + return longterm_wrapped_key_size; > + > + return ret; > +} > +EXPORT_SYMBOL(qcom_scm_generate_ice_key); > + > +/** > + * qcom_scm_prepare_ice_key() - Get per boot ephemeral wrapped key > + * @longterm_wrapped_key: the wrapped key > + * @longterm_wrapped_key_size: size of the wrapped key > + * @ephemeral_wrapped_key: ephemeral wrapped key to be returned > + * @ephemeral_wrapped_key_size: size of the ephemeral wrapped key > + * > + * Qualcomm wrapped keys (longterm keys) are rewrapped with a per-boot > + * ephemeral key for added protection. These are ephemeral in nature as > + * they are valid only for that boot. A create key IOCTL is used to > + * achieve this. These are the keys that are installed into the kernel > + * to be then unwrapped and programmed into ICE. > + * > + * This SCM call adds support for the create key IOCTL to interface > + * with the secure environment to rewrap the wrapped key with an > + * ephemeral wrapping key. > + * > + * Return: 0 on success; -errno on failure. > + */ > +int qcom_scm_prepare_ice_key(const u8 *longterm_wrapped_key, > + u32 longterm_wrapped_key_size, > + u8 *ephemeral_wrapped_key, > + u32 ephemeral_wrapped_key_size) > +{ > + struct qcom_scm_desc desc = { > + .svc = QCOM_SCM_SVC_ES, > + .cmd = QCOM_SCM_ES_PREPARE_ICE_KEY, > + .arginfo = QCOM_SCM_ARGS(4, QCOM_SCM_RO, > + QCOM_SCM_VAL, QCOM_SCM_RW, > + QCOM_SCM_VAL), > + .args[1] = longterm_wrapped_key_size, > + .args[3] = ephemeral_wrapped_key_size, > + .owner = ARM_SMCCC_OWNER_SIP, > + }; > + > + void *longterm_wrapped_keybuf, *ephemeral_wrapped_keybuf; > + dma_addr_t longterm_wrapped_key_phys, ephemeral_wrapped_key_phys; > + int ret; > + > + /* > + * Like qcom_scm_ice_set_key(), we use dma_alloc_coherent() to properly > + * get a physical address, while guaranteeing that we can zeroize the > + * key material later using memzero_explicit(). > + * > + */ > + longterm_wrapped_keybuf = dma_alloc_coherent(__scm->dev, > + longterm_wrapped_key_size, > + &longterm_wrapped_key_phys, GFP_KERNEL); > + if (!longterm_wrapped_keybuf) > + return -ENOMEM; > + ephemeral_wrapped_keybuf = dma_alloc_coherent(__scm->dev, > + ephemeral_wrapped_key_size, > + &ephemeral_wrapped_key_phys, GFP_KERNEL); > + if (!ephemeral_wrapped_keybuf) { > + ret = -ENOMEM; > + goto bail_keybuf; > + } > + > + memcpy(longterm_wrapped_keybuf, longterm_wrapped_key, > + longterm_wrapped_key_size); > + desc.args[0] = longterm_wrapped_key_phys; > + desc.args[2] = ephemeral_wrapped_key_phys; > + > + ret = qcom_scm_call(__scm->dev, &desc, NULL); > + if (!ret) > + memcpy(ephemeral_wrapped_key, ephemeral_wrapped_keybuf, > + ephemeral_wrapped_key_size); > + > + memzero_explicit(ephemeral_wrapped_keybuf, ephemeral_wrapped_key_size); > + dma_free_coherent(__scm->dev, ephemeral_wrapped_key_size, > + ephemeral_wrapped_keybuf, > + ephemeral_wrapped_key_phys); > + > +bail_keybuf: > + memzero_explicit(longterm_wrapped_keybuf, longterm_wrapped_key_size); > + dma_free_coherent(__scm->dev, longterm_wrapped_key_size, > + longterm_wrapped_keybuf, longterm_wrapped_key_phys); > + > + if (!ret) > + return ephemeral_wrapped_key_size; > + > + return ret; > +} > +EXPORT_SYMBOL(qcom_scm_prepare_ice_key); EXPORT_SYMBOL_GPL everywhere please. I understand that other places in this file uses EXPORT_SYMBOL but new additions can be _GPL. I will see if someone from my team can covert other symbols to _GPL as well in this file. ---Trilok Soni
On Wed, Jul 19, 2023 at 10:04:21AM -0700, Gaurav Kashyap wrote: > Storage encryption has two IOCTLs for creating, importing > and preparing keys for encryption. For wrapped keys, these > IOCTLs need to interface with the secure environment, which > require these SCM calls. > > generate_key: This is used to generate and return a longterm > wrapped key. Trustzone achieves this by generating > a key and then wrapping it using hwkm, returning > a wrapped keyblob. > import_key: The functionality is similar to generate, but here, > a raw key is imported into hwkm and a longterm wrapped > keyblob is returned. > prepare_key: The longterm wrapped key from import or generate > is made further secure by rewrapping it with a per-boot > ephemeral wrapped key before installing it to the linux > kernel for programming to ICE. > > Signed-off-by: Gaurav Kashyap <quic_gaurkash@quicinc.com> > --- > drivers/firmware/qcom_scm.c | 222 +++++++++++++++++++++++++ > drivers/firmware/qcom_scm.h | 3 + > include/linux/firmware/qcom/qcom_scm.h | 10 ++ > 3 files changed, 235 insertions(+) > > diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c > index 51062d5c7f7b..44dd1857747b 100644 > --- a/drivers/firmware/qcom_scm.c > +++ b/drivers/firmware/qcom_scm.c > @@ -1210,6 +1210,228 @@ int qcom_scm_derive_sw_secret(const u8 *wrapped_key, u32 wrapped_key_size, > } > EXPORT_SYMBOL(qcom_scm_derive_sw_secret); > > +/** > + * qcom_scm_generate_ice_key() - Generate a wrapped key for encryption. > + * @longterm_wrapped_key: the wrapped key returned after key generation "longterm" was long enough that you didn't feel it made sense in the description ;) Jokes aside, please follow the convention described in: https://www.kernel.org/doc/html/v4.10/process/coding-style.html#naming "key" or "wrapped_key" sounds sufficient to me. > + * @longterm_wrapped_key_size: size of the wrapped key to be returned. > + * > + * Qualcomm wrapped keys need to be generated in a trusted environment. > + * A generate key IOCTL call is used to achieve this. These are longterm > + * in nature as they need to be generated and wrapped only once per > + * requirement. > + * > + * This SCM calls adds support for the generate key IOCTL to interface > + * with the secure environment to generate and return a wrapped key.. I'm afraid I don't fully understand this sentence, please rework it. > + * > + * Return: 0 on success; -errno on failure. > + */ > +int qcom_scm_generate_ice_key(u8 *longterm_wrapped_key, > + u32 longterm_wrapped_key_size) > +{ > + struct qcom_scm_desc desc = { > + .svc = QCOM_SCM_SVC_ES, > + .cmd = QCOM_SCM_ES_GENERATE_ICE_KEY, > + .arginfo = QCOM_SCM_ARGS(2, QCOM_SCM_RW, > + QCOM_SCM_VAL), Leaving this line unwrapped brings you to 71 characters, you have 80 (with stretch of 100) as the limit. > + .args[1] = longterm_wrapped_key_size, > + .owner = ARM_SMCCC_OWNER_SIP, > + }; > + > + void *longterm_wrapped_keybuf; "buf" or "tmp" sounds sufficient. > + dma_addr_t longterm_wrapped_key_phys; "phys" or "addr" > + int ret; > + > + /* > + * Like qcom_scm_ice_set_key(), we use dma_alloc_coherent() to properly > + * get a physical address, while guaranteeing that we can zeroize the > + * key material later using memzero_explicit(). > + * > + */ > + longterm_wrapped_keybuf = dma_alloc_coherent(__scm->dev, > + longterm_wrapped_key_size, > + &longterm_wrapped_key_phys, GFP_KERNEL); > + if (!longterm_wrapped_keybuf) > + return -ENOMEM; > + > + desc.args[0] = longterm_wrapped_key_phys; > + > + ret = qcom_scm_call(__scm->dev, &desc, NULL); > + memcpy(longterm_wrapped_key, longterm_wrapped_keybuf, > + longterm_wrapped_key_size); The idiomatic way is to not touch the output buffer if the call fails, any particular reason for you to not follow this here? > + > + memzero_explicit(longterm_wrapped_keybuf, longterm_wrapped_key_size); > + dma_free_coherent(__scm->dev, longterm_wrapped_key_size, > + longterm_wrapped_keybuf, longterm_wrapped_key_phys); With better choice of variable names you might be able to leave this unwrapped (remember the guideline is 80, but you can go over that slightly if it benefits readability) > + > + if (!ret) > + return longterm_wrapped_key_size; It's also idiomatic to return early on errors. So please swap this around to make the successful exit at the end. > + > + return ret; > +} > +EXPORT_SYMBOL(qcom_scm_generate_ice_key); > + > +/** > + * qcom_scm_prepare_ice_key() - Get per boot ephemeral wrapped key > + * @longterm_wrapped_key: the wrapped key > + * @longterm_wrapped_key_size: size of the wrapped key > + * @ephemeral_wrapped_key: ephemeral wrapped key to be returned > + * @ephemeral_wrapped_key_size: size of the ephemeral wrapped key > + * > + * Qualcomm wrapped keys (longterm keys) are rewrapped with a per-boot > + * ephemeral key for added protection. These are ephemeral in nature as > + * they are valid only for that boot. A create key IOCTL is used to > + * achieve this. These are the keys that are installed into the kernel > + * to be then unwrapped and programmed into ICE. > + * > + * This SCM call adds support for the create key IOCTL to interface > + * with the secure environment to rewrap the wrapped key with an > + * ephemeral wrapping key. > + * > + * Return: 0 on success; -errno on failure. > + */ > +int qcom_scm_prepare_ice_key(const u8 *longterm_wrapped_key, > + u32 longterm_wrapped_key_size, > + u8 *ephemeral_wrapped_key, > + u32 ephemeral_wrapped_key_size) wrapped, wrapped_size, ephemeral, ephemeral_size perhaps? > +{ > + struct qcom_scm_desc desc = { > + .svc = QCOM_SCM_SVC_ES, > + .cmd = QCOM_SCM_ES_PREPARE_ICE_KEY, > + .arginfo = QCOM_SCM_ARGS(4, QCOM_SCM_RO, > + QCOM_SCM_VAL, QCOM_SCM_RW, > + QCOM_SCM_VAL), > + .args[1] = longterm_wrapped_key_size, > + .args[3] = ephemeral_wrapped_key_size, > + .owner = ARM_SMCCC_OWNER_SIP, > + }; > + > + void *longterm_wrapped_keybuf, *ephemeral_wrapped_keybuf; > + dma_addr_t longterm_wrapped_key_phys, ephemeral_wrapped_key_phys; > + int ret; > + > + /* > + * Like qcom_scm_ice_set_key(), we use dma_alloc_coherent() to properly > + * get a physical address, while guaranteeing that we can zeroize the > + * key material later using memzero_explicit(). > + * > + */ > + longterm_wrapped_keybuf = dma_alloc_coherent(__scm->dev, > + longterm_wrapped_key_size, > + &longterm_wrapped_key_phys, GFP_KERNEL); > + if (!longterm_wrapped_keybuf) > + return -ENOMEM; > + ephemeral_wrapped_keybuf = dma_alloc_coherent(__scm->dev, > + ephemeral_wrapped_key_size, > + &ephemeral_wrapped_key_phys, GFP_KERNEL); > + if (!ephemeral_wrapped_keybuf) { > + ret = -ENOMEM; > + goto bail_keybuf; > + } > + > + memcpy(longterm_wrapped_keybuf, longterm_wrapped_key, > + longterm_wrapped_key_size); > + desc.args[0] = longterm_wrapped_key_phys; > + desc.args[2] = ephemeral_wrapped_key_phys; > + > + ret = qcom_scm_call(__scm->dev, &desc, NULL); > + if (!ret) > + memcpy(ephemeral_wrapped_key, ephemeral_wrapped_keybuf, > + ephemeral_wrapped_key_size); > + > + memzero_explicit(ephemeral_wrapped_keybuf, ephemeral_wrapped_key_size); > + dma_free_coherent(__scm->dev, ephemeral_wrapped_key_size, > + ephemeral_wrapped_keybuf, > + ephemeral_wrapped_key_phys); > + > +bail_keybuf: Which "key"? Perhaps err_free_longterm_buf: > + memzero_explicit(longterm_wrapped_keybuf, longterm_wrapped_key_size); I don't see a reason to memzero_explicit(longterm_buf) in the bail_keybuf. Move this up and memzero_explicit() both buffers at the same time, then dma_free_coherent() them. > + dma_free_coherent(__scm->dev, longterm_wrapped_key_size, > + longterm_wrapped_keybuf, longterm_wrapped_key_phys); > + > + if (!ret) > + return ephemeral_wrapped_key_size; As above, flip the two cases. > + > + return ret; > +} > +EXPORT_SYMBOL(qcom_scm_prepare_ice_key); > + > +/** > + * qcom_scm_import_ice_key() - Import a wrapped key for encryption > + * @imported_key: the raw key that is imported > + * @imported_key_size: size of the key to be imported > + * @longterm_wrapped_key: the wrapped key to be returned > + * @longterm_wrapped_key_size: size of the wrapped key > + * > + * Conceptually, this is very similar to generate, the difference being, > + * here we want to import a raw key and return a longterm wrapped key > + * from it. THe same create key IOCTL is used to achieve this. > + * > + * This SCM call adds support for the create key IOCTL to interface with > + * the secure environment to import a raw key and generate a longterm > + * wrapped key. > + * > + * Return: 0 on success; -errno on failure. > + */ > +int qcom_scm_import_ice_key(const u8 *imported_key, u32 imported_key_size, > + u8 *longterm_wrapped_key, > + u32 longterm_wrapped_key_size) Same thing with naming here, please. > +{ > + struct qcom_scm_desc desc = { > + .svc = QCOM_SCM_SVC_ES, > + .cmd = QCOM_SCM_ES_IMPORT_ICE_KEY, > + .arginfo = QCOM_SCM_ARGS(4, QCOM_SCM_RO, > + QCOM_SCM_VAL, QCOM_SCM_RW, > + QCOM_SCM_VAL), > + .args[1] = imported_key_size, > + .args[3] = longterm_wrapped_key_size, > + .owner = ARM_SMCCC_OWNER_SIP, > + }; > + > + void *imported_keybuf, *longterm_wrapped_keybuf; > + dma_addr_t imported_key_phys, longterm_wrapped_key_phys; > + int ret; Declaration above and comment below are two separate "paragraphs", so a empty line between them would be good. > + /* > + * Like qcom_scm_ice_set_key(), we use dma_alloc_coherent() to properly > + * get a physical address, while guaranteeing that we can zeroize the > + * key material later using memzero_explicit(). > + * > + */ > + imported_keybuf = dma_alloc_coherent(__scm->dev, imported_key_size, > + &imported_key_phys, GFP_KERNEL); > + if (!imported_keybuf) > + return -ENOMEM; > + longterm_wrapped_keybuf = dma_alloc_coherent(__scm->dev, > + longterm_wrapped_key_size, > + &longterm_wrapped_key_phys, GFP_KERNEL); > + if (!longterm_wrapped_keybuf) { > + ret = -ENOMEM; > + goto bail_keybuf; > + } > + > + memcpy(imported_keybuf, imported_key, imported_key_size); > + desc.args[0] = imported_key_phys; > + desc.args[2] = longterm_wrapped_key_phys; > + > + ret = qcom_scm_call(__scm->dev, &desc, NULL); > + if (!ret) > + memcpy(longterm_wrapped_key, longterm_wrapped_keybuf, > + longterm_wrapped_key_size); > + > + memzero_explicit(longterm_wrapped_keybuf, longterm_wrapped_key_size); > + dma_free_coherent(__scm->dev, longterm_wrapped_key_size, > + longterm_wrapped_keybuf, longterm_wrapped_key_phys); > +bail_keybuf: > + memzero_explicit(imported_keybuf, imported_key_size); As above, please move this together with the other memzero_explicit(). > + dma_free_coherent(__scm->dev, imported_key_size, imported_keybuf, > + imported_key_phys); > + > + if (!ret) And flip these. Regards, Bjorn
On Fri, Jul 21, 2023 at 08:40:32PM -0700, Bjorn Andersson wrote: > On Wed, Jul 19, 2023 at 10:04:21AM -0700, Gaurav Kashyap wrote: > > Storage encryption has two IOCTLs for creating, importing > > and preparing keys for encryption. For wrapped keys, these > > IOCTLs need to interface with the secure environment, which > > require these SCM calls. > > > > generate_key: This is used to generate and return a longterm > > wrapped key. Trustzone achieves this by generating > > a key and then wrapping it using hwkm, returning > > a wrapped keyblob. > > import_key: The functionality is similar to generate, but here, > > a raw key is imported into hwkm and a longterm wrapped > > keyblob is returned. > > prepare_key: The longterm wrapped key from import or generate > > is made further secure by rewrapping it with a per-boot > > ephemeral wrapped key before installing it to the linux > > kernel for programming to ICE. > > > > Signed-off-by: Gaurav Kashyap <quic_gaurkash@quicinc.com> > > --- > > drivers/firmware/qcom_scm.c | 222 +++++++++++++++++++++++++ > > drivers/firmware/qcom_scm.h | 3 + > > include/linux/firmware/qcom/qcom_scm.h | 10 ++ > > 3 files changed, 235 insertions(+) > > > > diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c > > index 51062d5c7f7b..44dd1857747b 100644 > > --- a/drivers/firmware/qcom_scm.c > > +++ b/drivers/firmware/qcom_scm.c > > @@ -1210,6 +1210,228 @@ int qcom_scm_derive_sw_secret(const u8 *wrapped_key, u32 wrapped_key_size, > > } > > EXPORT_SYMBOL(qcom_scm_derive_sw_secret); > > > > +/** > > + * qcom_scm_generate_ice_key() - Generate a wrapped key for encryption. > > + * @longterm_wrapped_key: the wrapped key returned after key generation > > "longterm" was long enough that you didn't feel it made sense in the > description ;) > > Jokes aside, please follow the convention described in: > https://www.kernel.org/doc/html/v4.10/process/coding-style.html#naming > > "key" or "wrapped_key" sounds sufficient to me. The naming I use in my most recent patchset that adds support for hardware-wrapped inline encryption keys to the block layer and fscrypt (https://lore.kernel.org/linux-block/20221216203636.81491-1-ebiggers@kernel.org/), which this patchset is based on, is 'lt_key' for a longterm wrapped key and 'eph_key' for an ephemerally-wrapped key. > > +int qcom_scm_prepare_ice_key(const u8 *longterm_wrapped_key, > > + u32 longterm_wrapped_key_size, > > + u8 *ephemeral_wrapped_key, > > + u32 ephemeral_wrapped_key_size) > > wrapped, wrapped_size, ephemeral, ephemeral_size perhaps? lt_key, lt_key_size, eph_key, eph_key_size. - Eric
On Fri, Jul 21, 2023 at 09:11:13PM -0700, Eric Biggers wrote: > On Fri, Jul 21, 2023 at 08:40:32PM -0700, Bjorn Andersson wrote: > > On Wed, Jul 19, 2023 at 10:04:21AM -0700, Gaurav Kashyap wrote: > > > Storage encryption has two IOCTLs for creating, importing > > > and preparing keys for encryption. For wrapped keys, these > > > IOCTLs need to interface with the secure environment, which > > > require these SCM calls. > > > > > > generate_key: This is used to generate and return a longterm > > > wrapped key. Trustzone achieves this by generating > > > a key and then wrapping it using hwkm, returning > > > a wrapped keyblob. > > > import_key: The functionality is similar to generate, but here, > > > a raw key is imported into hwkm and a longterm wrapped > > > keyblob is returned. > > > prepare_key: The longterm wrapped key from import or generate > > > is made further secure by rewrapping it with a per-boot > > > ephemeral wrapped key before installing it to the linux > > > kernel for programming to ICE. > > > > > > Signed-off-by: Gaurav Kashyap <quic_gaurkash@quicinc.com> > > > --- > > > drivers/firmware/qcom_scm.c | 222 +++++++++++++++++++++++++ > > > drivers/firmware/qcom_scm.h | 3 + > > > include/linux/firmware/qcom/qcom_scm.h | 10 ++ > > > 3 files changed, 235 insertions(+) > > > > > > diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c > > > index 51062d5c7f7b..44dd1857747b 100644 > > > --- a/drivers/firmware/qcom_scm.c > > > +++ b/drivers/firmware/qcom_scm.c > > > @@ -1210,6 +1210,228 @@ int qcom_scm_derive_sw_secret(const u8 *wrapped_key, u32 wrapped_key_size, > > > } > > > EXPORT_SYMBOL(qcom_scm_derive_sw_secret); > > > > > > +/** > > > + * qcom_scm_generate_ice_key() - Generate a wrapped key for encryption. > > > + * @longterm_wrapped_key: the wrapped key returned after key generation > > > > "longterm" was long enough that you didn't feel it made sense in the > > description ;) > > > > Jokes aside, please follow the convention described in: > > https://www.kernel.org/doc/html/v4.10/process/coding-style.html#naming > > > > "key" or "wrapped_key" sounds sufficient to me. > > The naming I use in my most recent patchset that adds support for > hardware-wrapped inline encryption keys to the block layer and fscrypt > (https://lore.kernel.org/linux-block/20221216203636.81491-1-ebiggers@kernel.org/), > which this patchset is based on, is 'lt_key' for a longterm wrapped key and > 'eph_key' for an ephemerally-wrapped key. > Excellent, using familiar names is good! Regards, Bjorn
diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c index 51062d5c7f7b..44dd1857747b 100644 --- a/drivers/firmware/qcom_scm.c +++ b/drivers/firmware/qcom_scm.c @@ -1210,6 +1210,228 @@ int qcom_scm_derive_sw_secret(const u8 *wrapped_key, u32 wrapped_key_size, } EXPORT_SYMBOL(qcom_scm_derive_sw_secret); +/** + * qcom_scm_generate_ice_key() - Generate a wrapped key for encryption. + * @longterm_wrapped_key: the wrapped key returned after key generation + * @longterm_wrapped_key_size: size of the wrapped key to be returned. + * + * Qualcomm wrapped keys need to be generated in a trusted environment. + * A generate key IOCTL call is used to achieve this. These are longterm + * in nature as they need to be generated and wrapped only once per + * requirement. + * + * This SCM calls adds support for the generate key IOCTL to interface + * with the secure environment to generate and return a wrapped key.. + * + * Return: 0 on success; -errno on failure. + */ +int qcom_scm_generate_ice_key(u8 *longterm_wrapped_key, + u32 longterm_wrapped_key_size) +{ + struct qcom_scm_desc desc = { + .svc = QCOM_SCM_SVC_ES, + .cmd = QCOM_SCM_ES_GENERATE_ICE_KEY, + .arginfo = QCOM_SCM_ARGS(2, QCOM_SCM_RW, + QCOM_SCM_VAL), + .args[1] = longterm_wrapped_key_size, + .owner = ARM_SMCCC_OWNER_SIP, + }; + + void *longterm_wrapped_keybuf; + dma_addr_t longterm_wrapped_key_phys; + int ret; + + /* + * Like qcom_scm_ice_set_key(), we use dma_alloc_coherent() to properly + * get a physical address, while guaranteeing that we can zeroize the + * key material later using memzero_explicit(). + * + */ + longterm_wrapped_keybuf = dma_alloc_coherent(__scm->dev, + longterm_wrapped_key_size, + &longterm_wrapped_key_phys, GFP_KERNEL); + if (!longterm_wrapped_keybuf) + return -ENOMEM; + + desc.args[0] = longterm_wrapped_key_phys; + + ret = qcom_scm_call(__scm->dev, &desc, NULL); + memcpy(longterm_wrapped_key, longterm_wrapped_keybuf, + longterm_wrapped_key_size); + + memzero_explicit(longterm_wrapped_keybuf, longterm_wrapped_key_size); + dma_free_coherent(__scm->dev, longterm_wrapped_key_size, + longterm_wrapped_keybuf, longterm_wrapped_key_phys); + + if (!ret) + return longterm_wrapped_key_size; + + return ret; +} +EXPORT_SYMBOL(qcom_scm_generate_ice_key); + +/** + * qcom_scm_prepare_ice_key() - Get per boot ephemeral wrapped key + * @longterm_wrapped_key: the wrapped key + * @longterm_wrapped_key_size: size of the wrapped key + * @ephemeral_wrapped_key: ephemeral wrapped key to be returned + * @ephemeral_wrapped_key_size: size of the ephemeral wrapped key + * + * Qualcomm wrapped keys (longterm keys) are rewrapped with a per-boot + * ephemeral key for added protection. These are ephemeral in nature as + * they are valid only for that boot. A create key IOCTL is used to + * achieve this. These are the keys that are installed into the kernel + * to be then unwrapped and programmed into ICE. + * + * This SCM call adds support for the create key IOCTL to interface + * with the secure environment to rewrap the wrapped key with an + * ephemeral wrapping key. + * + * Return: 0 on success; -errno on failure. + */ +int qcom_scm_prepare_ice_key(const u8 *longterm_wrapped_key, + u32 longterm_wrapped_key_size, + u8 *ephemeral_wrapped_key, + u32 ephemeral_wrapped_key_size) +{ + struct qcom_scm_desc desc = { + .svc = QCOM_SCM_SVC_ES, + .cmd = QCOM_SCM_ES_PREPARE_ICE_KEY, + .arginfo = QCOM_SCM_ARGS(4, QCOM_SCM_RO, + QCOM_SCM_VAL, QCOM_SCM_RW, + QCOM_SCM_VAL), + .args[1] = longterm_wrapped_key_size, + .args[3] = ephemeral_wrapped_key_size, + .owner = ARM_SMCCC_OWNER_SIP, + }; + + void *longterm_wrapped_keybuf, *ephemeral_wrapped_keybuf; + dma_addr_t longterm_wrapped_key_phys, ephemeral_wrapped_key_phys; + int ret; + + /* + * Like qcom_scm_ice_set_key(), we use dma_alloc_coherent() to properly + * get a physical address, while guaranteeing that we can zeroize the + * key material later using memzero_explicit(). + * + */ + longterm_wrapped_keybuf = dma_alloc_coherent(__scm->dev, + longterm_wrapped_key_size, + &longterm_wrapped_key_phys, GFP_KERNEL); + if (!longterm_wrapped_keybuf) + return -ENOMEM; + ephemeral_wrapped_keybuf = dma_alloc_coherent(__scm->dev, + ephemeral_wrapped_key_size, + &ephemeral_wrapped_key_phys, GFP_KERNEL); + if (!ephemeral_wrapped_keybuf) { + ret = -ENOMEM; + goto bail_keybuf; + } + + memcpy(longterm_wrapped_keybuf, longterm_wrapped_key, + longterm_wrapped_key_size); + desc.args[0] = longterm_wrapped_key_phys; + desc.args[2] = ephemeral_wrapped_key_phys; + + ret = qcom_scm_call(__scm->dev, &desc, NULL); + if (!ret) + memcpy(ephemeral_wrapped_key, ephemeral_wrapped_keybuf, + ephemeral_wrapped_key_size); + + memzero_explicit(ephemeral_wrapped_keybuf, ephemeral_wrapped_key_size); + dma_free_coherent(__scm->dev, ephemeral_wrapped_key_size, + ephemeral_wrapped_keybuf, + ephemeral_wrapped_key_phys); + +bail_keybuf: + memzero_explicit(longterm_wrapped_keybuf, longterm_wrapped_key_size); + dma_free_coherent(__scm->dev, longterm_wrapped_key_size, + longterm_wrapped_keybuf, longterm_wrapped_key_phys); + + if (!ret) + return ephemeral_wrapped_key_size; + + return ret; +} +EXPORT_SYMBOL(qcom_scm_prepare_ice_key); + +/** + * qcom_scm_import_ice_key() - Import a wrapped key for encryption + * @imported_key: the raw key that is imported + * @imported_key_size: size of the key to be imported + * @longterm_wrapped_key: the wrapped key to be returned + * @longterm_wrapped_key_size: size of the wrapped key + * + * Conceptually, this is very similar to generate, the difference being, + * here we want to import a raw key and return a longterm wrapped key + * from it. THe same create key IOCTL is used to achieve this. + * + * This SCM call adds support for the create key IOCTL to interface with + * the secure environment to import a raw key and generate a longterm + * wrapped key. + * + * Return: 0 on success; -errno on failure. + */ +int qcom_scm_import_ice_key(const u8 *imported_key, u32 imported_key_size, + u8 *longterm_wrapped_key, + u32 longterm_wrapped_key_size) +{ + struct qcom_scm_desc desc = { + .svc = QCOM_SCM_SVC_ES, + .cmd = QCOM_SCM_ES_IMPORT_ICE_KEY, + .arginfo = QCOM_SCM_ARGS(4, QCOM_SCM_RO, + QCOM_SCM_VAL, QCOM_SCM_RW, + QCOM_SCM_VAL), + .args[1] = imported_key_size, + .args[3] = longterm_wrapped_key_size, + .owner = ARM_SMCCC_OWNER_SIP, + }; + + void *imported_keybuf, *longterm_wrapped_keybuf; + dma_addr_t imported_key_phys, longterm_wrapped_key_phys; + int ret; + /* + * Like qcom_scm_ice_set_key(), we use dma_alloc_coherent() to properly + * get a physical address, while guaranteeing that we can zeroize the + * key material later using memzero_explicit(). + * + */ + imported_keybuf = dma_alloc_coherent(__scm->dev, imported_key_size, + &imported_key_phys, GFP_KERNEL); + if (!imported_keybuf) + return -ENOMEM; + longterm_wrapped_keybuf = dma_alloc_coherent(__scm->dev, + longterm_wrapped_key_size, + &longterm_wrapped_key_phys, GFP_KERNEL); + if (!longterm_wrapped_keybuf) { + ret = -ENOMEM; + goto bail_keybuf; + } + + memcpy(imported_keybuf, imported_key, imported_key_size); + desc.args[0] = imported_key_phys; + desc.args[2] = longterm_wrapped_key_phys; + + ret = qcom_scm_call(__scm->dev, &desc, NULL); + if (!ret) + memcpy(longterm_wrapped_key, longterm_wrapped_keybuf, + longterm_wrapped_key_size); + + memzero_explicit(longterm_wrapped_keybuf, longterm_wrapped_key_size); + dma_free_coherent(__scm->dev, longterm_wrapped_key_size, + longterm_wrapped_keybuf, longterm_wrapped_key_phys); +bail_keybuf: + memzero_explicit(imported_keybuf, imported_key_size); + dma_free_coherent(__scm->dev, imported_key_size, imported_keybuf, + imported_key_phys); + + if (!ret) + return longterm_wrapped_key_size; + + return ret; +} +EXPORT_SYMBOL(qcom_scm_import_ice_key); + /** * qcom_scm_hdcp_available() - Check if secure environment supports HDCP. * diff --git a/drivers/firmware/qcom_scm.h b/drivers/firmware/qcom_scm.h index c145cdc71ff8..fa6164bef54f 100644 --- a/drivers/firmware/qcom_scm.h +++ b/drivers/firmware/qcom_scm.h @@ -120,6 +120,9 @@ extern int scm_legacy_call(struct device *dev, const struct qcom_scm_desc *desc, #define QCOM_SCM_ES_INVALIDATE_ICE_KEY 0x03 #define QCOM_SCM_ES_CONFIG_SET_ICE_KEY 0x04 #define QCOM_SCM_ES_DERIVE_SW_SECRET 0x07 +#define QCOM_SCM_ES_GENERATE_ICE_KEY 0x08 +#define QCOM_SCM_ES_PREPARE_ICE_KEY 0x09 +#define QCOM_SCM_ES_IMPORT_ICE_KEY 0xA #define QCOM_SCM_SVC_HDCP 0x11 #define QCOM_SCM_HDCP_INVOKE 0x01 diff --git a/include/linux/firmware/qcom/qcom_scm.h b/include/linux/firmware/qcom/qcom_scm.h index 20f5d0b7dfd4..104666123e4d 100644 --- a/include/linux/firmware/qcom/qcom_scm.h +++ b/include/linux/firmware/qcom/qcom_scm.h @@ -112,6 +112,16 @@ extern int qcom_scm_ice_set_key(u32 index, const u8 *key, u32 key_size, extern int qcom_scm_derive_sw_secret(const u8 *wrapped_key, u32 wrapped_key_size, u8 *sw_secret, u32 secret_size); +extern int qcom_scm_generate_ice_key(u8 *longterm_wrapped_key, + u32 longterm_wrapped_key_size); +extern int qcom_scm_prepare_ice_key(const u8 *longterm_wrapped_key, + u32 longterm_wrapped_key_size, + u8 *ephemeral_wrapped_key, + u32 ephemeral_wrapped_key_size); +extern int qcom_scm_import_ice_key(const u8 *imported_key, + u32 imported_key_size, + u8 *longterm_wrapped_key, + u32 longterm_wrapped_key_size); extern bool qcom_scm_hdcp_available(void); extern int qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt,
Storage encryption has two IOCTLs for creating, importing and preparing keys for encryption. For wrapped keys, these IOCTLs need to interface with the secure environment, which require these SCM calls. generate_key: This is used to generate and return a longterm wrapped key. Trustzone achieves this by generating a key and then wrapping it using hwkm, returning a wrapped keyblob. import_key: The functionality is similar to generate, but here, a raw key is imported into hwkm and a longterm wrapped keyblob is returned. prepare_key: The longterm wrapped key from import or generate is made further secure by rewrapping it with a per-boot ephemeral wrapped key before installing it to the linux kernel for programming to ICE. Signed-off-by: Gaurav Kashyap <quic_gaurkash@quicinc.com> --- drivers/firmware/qcom_scm.c | 222 +++++++++++++++++++++++++ drivers/firmware/qcom_scm.h | 3 + include/linux/firmware/qcom/qcom_scm.h | 10 ++ 3 files changed, 235 insertions(+)