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[op-tee] [PATCH v2] Documentation: tee: Document TEE kernel interface

by Sumit Garg

Update documentation with TEE bus infrastructure which provides an interface for kernel client drivers to communicate with corresponding Trusted Application. Signed-off-by: Sumit Garg <sumit.garg(a)linaro.org> --- Changes in v2: - Add TEE client driver example snippet. Documentation/tee.txt | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) diff --git a/Documentation/tee.txt b/Documentation/tee.txt index c8fad81..350dd40 100644 --- a/Documentation/tee.txt +++ b/Documentation/tee.txt @@ -53,6 +53,66 @@ clients, forward them to the TEE and send back the results. In the case of supplicants the communication goes in the other direction, the TEE sends requests to the supplicant which then sends back the result. +The TEE kernel interface +======================== + +Kernel provides a TEE bus infrastructure where a Trusted Application is +represented as a device identified via Universally Unique Identifier (UUID) and +client drivers register a table of supported device UUIDs. + +TEE bus infrastructure registers following APIs: +- match(): iterates over the client driver UUID table to find a corresponding + match for device UUID. If a match is found, then this particular device is + probed via corresponding probe API registered by the client driver. This + process happens whenever a device or a client driver is registered with TEE + bus. +- uevent(): notifies user-space (udev) whenever a new device is registered on + TEE bus for auto-loading of modularized client drivers. + +TEE bus device enumeration is specific to underlying TEE implementation, so it +is left open for TEE drivers to provide corresponding implementation. + +Then TEE client driver can talk to a matched Trusted Application using APIs +listed in include/linux/tee_drv.h. + +TEE client driver example +------------------------- + +Suppose a TEE client driver needs to communicate with a Trusted Application +having UUID: ``ac6a4085-0e82-4c33-bf98-8eb8e118b6c2``, so driver registration +snippet would look like:: + + static const struct tee_client_device_id client_id_table[] = { + {UUID_INIT(0xac6a4085, 0x0e82, 0x4c33, + 0xbf, 0x98, 0x8e, 0xb8, 0xe1, 0x18, 0xb6, 0xc2)}, + {} + }; + + MODULE_DEVICE_TABLE(tee, client_id_table); + + static struct tee_client_driver client_driver = { + .id_table = client_id_table, + .driver = { + .name = DRIVER_NAME, + .bus = &tee_bus_type, + .probe = client_probe, + .remove = client_remove, + }, + }; + + static int __init client_init(void) + { + return driver_register(&client_driver.driver); + } + + static void __exit client_exit(void) + { + driver_unregister(&client_driver.driver); + } + + module_init(client_init); + module_exit(client_exit); + OP-TEE driver ============= @@ -112,6 +172,14 @@ kernel are handled by the kernel driver. Other RPC messages will be forwarded to tee-supplicant without further involvement of the driver, except switching shared memory buffer representation. +OP-TEE device enumeration +------------------------- + +OP-TEE provides a pseudo Trusted Application: drivers/tee/optee/device.c in +order to support device enumeration. In other words, OP-TEE driver invokes this +application to retrieve a list of Trusted Applications which can be registered +as devices on the TEE bus. + AMD-TEE driver ============== -- 2.7.4

4 years, 5 months

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OP-TEE Development Guidance

by Muhammad Saad

Hello All, First, I hope you are safe and doing fine in the unfortunate COVID-19 situation. I am a Ph.D. student at the University of Central Florida. Currently, I am working on a TEE-based prototype application for a proof-of-concept. Since I am totally new in this domain, so it is taking some effort. I have a few questions and I hope you guys can help me in that. At present, I am able to set up OP-TEE on Qemu and run the examples on the normal world and the secure world. Additionally, I tweaked a few parameters (ie., the integer value in the main.c) for the CA and the addition and subtraction sequence in the TA. Upon building it again (cd/build/make all run), it seems to work. However, if I need to pass a normal string to the TA and the TA computes Sha256 of the string and returns the value, what steps do I need to take? In other words, how can I pass a tuple from the TA to the CA and obtain the Hash of the tuple. Additionally, if I am able to do that by tailoring the HelloWorld examples, how can I develop new CA and TA with unique UUID and perform the same procedure. Finally, instead of doing the entire (cd/build/make all run), is there a method by which I can simply build the application and alone and run it on Qemu? I understand that these must be trivial questions, however, I will deeply appreciate if you can help me in figuring them out. Best, Saad

4 years, 5 months

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[op-tee] [PATCH v5 0/4] Introduce TEE based Trusted Keys support

by Sumit Garg

Add support for TEE based trusted keys where TEE provides the functionality to seal and unseal trusted keys using hardware unique key. Also, this is an alternative in case platform doesn't possess a TPM device. This patch-set has been tested with OP-TEE based early TA which is already merged in upstream [1]. [1] https://github.com/OP-TEE/optee_os/commit/f86ab8e7e0de869dfa25ca05a37ee070d… Changes in v5: 1. Drop dynamic detection of trust source and use compile time flags instead. 2. Rename trusted_common.c -> trusted_core.c. 3. Rename callback: cleanup() -> exit(). 4. Drop "tk" acronym. 5. Other misc. comments. 6. Added review tags for patch #3 and #4. Changes in v4: 1. Pushed independent TEE features separately: - Part of recent TEE PR: https://lkml.org/lkml/2020/5/4/1062 2. Updated trusted-encrypted doc with TEE as a new trust source. 3. Rebased onto latest tpmdd/master. Changes in v3: 1. Update patch #2 to support registration of multiple kernel pages. 2. Incoporate dependency patch #4 in this patch-set: https://patchwork.kernel.org/patch/11091435/ Changes in v2: 1. Add reviewed-by tags for patch #1 and #2. 2. Incorporate comments from Jens for patch #3. 3. Switch to use generic trusted keys framework. Sumit Garg (4): KEYS: trusted: Add generic trusted keys framework KEYS: trusted: Introduce TEE based Trusted Keys doc: trusted-encrypted: updates with TEE as a new trust source MAINTAINERS: Add entry for TEE based Trusted Keys Documentation/security/keys/trusted-encrypted.rst | 203 ++++++++++--- MAINTAINERS | 8 + include/keys/trusted-type.h | 48 ++++ include/keys/trusted_tee.h | 66 +++++ include/keys/trusted_tpm.h | 15 - security/keys/Kconfig | 31 +- security/keys/trusted-keys/Makefile | 6 +- security/keys/trusted-keys/trusted_core.c | 321 +++++++++++++++++++++ security/keys/trusted-keys/trusted_tee.c | 280 ++++++++++++++++++ security/keys/trusted-keys/trusted_tpm1.c | 335 ++++------------------ 10 files changed, 981 insertions(+), 332 deletions(-) create mode 100644 include/keys/trusted_tee.h create mode 100644 security/keys/trusted-keys/trusted_core.c create mode 100644 security/keys/trusted-keys/trusted_tee.c -- 2.7.4

4 years, 5 months

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[op-tee] [PATCH] MAINTAINERS: change tee mailing list

by Jens Wiklander

The old TEE mailing list tee-dev(a)lists.linaro.org is about to be retired. From now on please use op-tee(a)lists.trustedfirmware.org instead. Signed-off-by: Jens Wiklander <jens.wiklander(a)linaro.org> --- MAINTAINERS | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/MAINTAINERS b/MAINTAINERS index 68f21d46614c..772448e36203 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -12691,13 +12691,13 @@ F: arch/mips/boot/dts/ralink/omega2p.dts OP-TEE DRIVER M: Jens Wiklander <jens.wiklander(a)linaro.org> -L: tee-dev(a)lists.linaro.org +L: op-tee(a)lists.trustedfirmware.org S: Maintained F: drivers/tee/optee/ OP-TEE RANDOM NUMBER GENERATOR (RNG) DRIVER M: Sumit Garg <sumit.garg(a)linaro.org> -L: tee-dev(a)lists.linaro.org +L: op-tee(a)lists.trustedfirmware.org S: Maintained F: drivers/char/hw_random/optee-rng.c @@ -16759,7 +16759,7 @@ F: include/media/i2c/tw9910.h TEE SUBSYSTEM M: Jens Wiklander <jens.wiklander(a)linaro.org> -L: tee-dev(a)lists.linaro.org +L: op-tee(a)lists.trustedfirmware.org S: Maintained F: Documentation/tee.txt F: drivers/tee/ -- 2.25.1

4 years, 5 months

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[op-tee] Issue with __attribute__((constructor)) and -Os -fno-common

by Jerome Forissier

Hi, I think that Clang erroneously discards a function annotated with __attribute__((constructor)) when flags -Os -fno-common are given. Test case below. What do you think? Thanks. ----8<--------8<--------8<--------8<--------8<--------8<-------- $ cat ctor.c int val; static void __attribute__((constructor)) init_fn(void) { val = 1; } int main(int argc, char *argv[]) { return val; } ----8<--------8<--------8<--------8<--------8<--------8<-------- Here is what I observed: - Clang (10.0.0-4ubuntu1) with -Os -fno-common: function init_fn() is NOT emitted, - Clang (10.0.0-4ubuntu1) with no flag, or only -Os or -fno-common: init_fn() is present as expected, - GCC (Ubuntu 9.3.0-10ubuntu1) with the same flags: init_fn() is present too, - Since https://reviews.llvm.org/D75056, -fno-common is the default and therefore -Os is enough to cause the issue. ----8<--------8<--------8<--------8<--------8<--------8<-------- $ clang --target=arm-linux-gnueabihf -Os -fno-common -S ctor.c \ -o /dev/stdout | grep init_fn $ clang --target=arm-linux-gnueabihf -Os -S ctor.c \ -o /dev/stdout | grep init_fn .p2align 2 @ -- Begin function init_fn .type init_fn,%function .code 32 @ @init_fn init_fn: .size init_fn, .Lfunc_end0-init_fn .long init_fn(target1) .addrsig_sym init_fn $ clang --target=arm-linux-gnueabihf -fno-common -S ctor.c \ -o /dev/stdout | grep init_fn .p2align 2 @ -- Begin function init_fn .type init_fn,%function .code 32 @ @init_fn init_fn: .size init_fn, .Lfunc_end0-init_fn .long init_fn(target1) .addrsig_sym init_fn $ arm-linux-gnueabihf-gcc -Os -fno-common -S ctor.c \ -o /dev/stdout | grep init_fn .type init_fn, %function init_fn: .size init_fn, .-init_fn .word init_fn(target1) ----8<--------8<--------8<--------8<--------8<--------8<-------- -- Jerome

4 years, 5 months

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[op-tee] [PATCH] Documentation: tee: Document TEE kernel interface

by Sumit Garg

Update documentation with TEE bus infrastructure which provides an interface for kernel client drivers to communicate with corresponding Trusted Application. Signed-off-by: Sumit Garg <sumit.garg(a)linaro.org> --- Documentation/tee.txt | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/Documentation/tee.txt b/Documentation/tee.txt index c8fad81..428d3b5 100644 --- a/Documentation/tee.txt +++ b/Documentation/tee.txt @@ -53,6 +53,28 @@ clients, forward them to the TEE and send back the results. In the case of supplicants the communication goes in the other direction, the TEE sends requests to the supplicant which then sends back the result. +The TEE kernel interface +======================== + +Kernel provides a TEE bus infrastructure where a Trusted Application is +represented as a device identified via Universally Unique Identifier (UUID) and +client drivers register a table of supported device UUIDs. + +TEE bus infrastructure registers following APIs: +- match(): iterates over the client driver UUID table to find a corresponding + match for device UUID. If a match is found, then this particular device is + probed via corresponding probe API registered by the client driver. This + process happens whenever a device or a client driver is registered with TEE + bus. +- uevent(): notifies user-space (udev) whenever a new device is registered on + TEE bus for auto-loading of modularized client drivers. + +TEE bus device enumeration is specific to underlying TEE implementation, so it +is left open for TEE drivers to provide corresponding implementation. + +Then TEE client driver can talk to a matched Trusted Application using APIs +listed in include/linux/tee_drv.h. + OP-TEE driver ============= @@ -112,6 +134,14 @@ kernel are handled by the kernel driver. Other RPC messages will be forwarded to tee-supplicant without further involvement of the driver, except switching shared memory buffer representation. +OP-TEE device enumeration +------------------------- + +OP-TEE provides a pseudo Trusted Application: drivers/tee/optee/device.c in +order to support device enumeration. In other words, OP-TEE driver invokes this +application to retrieve a list of Trusted Applications which can be registered +as devices on the TEE bus. + AMD-TEE driver ============== -- 2.7.4

4 years, 5 months

2
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[op-tee] [PATCH v4 0/4] Introduce TEE based Trusted Keys support

by Sumit Garg

Add support for TEE based trusted keys where TEE provides the functionality to seal and unseal trusted keys using hardware unique key. Also, this is an alternative in case platform doesn't possess a TPM device. This patch-set has been tested with OP-TEE based early TA which can be found here [1]. [1] https://github.com/OP-TEE/optee_os/pull/3838 Changes in v4: 1. Pushed independent TEE features separately: - Part of recent TEE PR: https://lkml.org/lkml/2020/5/4/1062 2. Updated trusted-encrypted doc with TEE as a new trust source. 3. Rebased onto latest tpmdd/master. Changes in v3: 1. Update patch #2 to support registration of multiple kernel pages. 2. Incoporate dependency patch #4 in this patch-set: https://patchwork.kernel.org/patch/11091435/ Changes in v2: 1. Add reviewed-by tags for patch #1 and #2. 2. Incorporate comments from Jens for patch #3. 3. Switch to use generic trusted keys framework. Sumit Garg (4): KEYS: trusted: Add generic trusted keys framework KEYS: trusted: Introduce TEE based Trusted Keys doc: trusted-encrypted: updates with TEE as a new trust source MAINTAINERS: Add entry for TEE based Trusted Keys Documentation/security/keys/trusted-encrypted.rst | 203 ++++++++++--- MAINTAINERS | 8 + include/keys/trusted-type.h | 48 ++++ include/keys/trusted_tee.h | 66 +++++ include/keys/trusted_tpm.h | 15 - security/keys/Kconfig | 3 + security/keys/trusted-keys/Makefile | 2 + security/keys/trusted-keys/trusted_common.c | 336 ++++++++++++++++++++++ security/keys/trusted-keys/trusted_tee.c | 282 ++++++++++++++++++ security/keys/trusted-keys/trusted_tpm1.c | 335 ++++----------------- 10 files changed, 974 insertions(+), 324 deletions(-) create mode 100644 include/keys/trusted_tee.h create mode 100644 security/keys/trusted-keys/trusted_common.c create mode 100644 security/keys/trusted-keys/trusted_tee.c -- 2.7.4

4 years, 5 months

2
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[op-tee] Aarch64: unaligned access despite -mstrict-align

by Jerome Forissier

Hi, I experienced a crash in code compiled with Clang 10.0.0 due to a misaligned 64-bit data access. The (ARMv8) CPU is configured with SCTL.A == 1 (alignment check enable). With SCTLR.A == 0 the code runs as expected. After some investigation I came up with the following reproducer: ---8<-------8<-------8<-------8<-------8<-------8<-------8<------- $ cat test.c extern char *g; int memcmp(const void *s1, const void *s2, unsigned long n); int f(void *c) { return memcmp(g, c, 16); } $ clang --target=aarch64-linux-gnu -Os -mstrict-align -S test.c $ cat test.s .text .file "test.c" .globl f // -- Begin function f .p2align 2 .type f,@function f: // @f // %bb.0: adrp x8, g ldr x10, [x8, :lo12:g] ldr x9, [x0] ldr x8, [x10] rev x9, x9 rev x8, x8 cmp x8, x9 b.ne .LBB0_3 // %bb.1: ldr x8, [x10, #8] ldr x9, [x0, #8] rev x8, x8 rev x9, x9 cmp x8, x9 b.ne .LBB0_3 // %bb.2: mov w0, wzr ret .LBB0_3: cmp x8, x9 mov w8, #-1 cneg w0, w8, hs ret .Lfunc_end0: .size f, .Lfunc_end0-f // -- End function .ident "clang version 10.0.0-4ubuntu1 " .section ".note.GNU-stack","",@progbits .addrsig ---8<-------8<-------8<-------8<-------8<-------8<-------8<------- Note the 'ldr x9, [x0]'. At this point there is no guarantee that x0 is a multiple of 8, so why is Clang generating this code? Thanks, -- Jerome

4 years, 5 months

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[op-tee] Maximum line length in the Linux kernel

by Jérôme Forissier

FYI, the "80 column" rule has just evolved a bit: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… So it is now s "<= 80 columns preferred, but up to 100 is OK". Since we are mostly following the Linux coding style, I think this should apply to OP-TEE as well. Personally, I think it's a good thing as it will help avoid some silly line breaks in long debug messages for instance. -- Jerome

4 years, 5 months

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[op-tee] OP-TEE 3.9.0 has been released

by Jens Wiklander

[BCC all OP-TEE maintainers] Hi, FYI, I have just finalized the OP-TEE 3.9.0 release (changelog [1]). As always, thank you to everyone who contributed to OP-TEE and participated in testing this release [2]. [1] https://github.com/OP-TEE/optee_os/blob/3.9.0/CHANGELOG.md [2] https://github.com/OP-TEE/optee_os/commit/af141c61fe7a2430f3b4bb89661d84141… Regards, Jens

4 years, 6 months

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