Instead of using CAP_SYS_ADMIN which is restricted to the root user,
check the file mode for write permissions before executing commands that
can affect the platform. This allows for more fine-grained access
control to the SEV ioctl interface. This would allow a SEV-only user
or group the ability to administer the platform without requiring them
to be root or granting them overly powerful permissions.
For example:
chown root:root /dev/sev
chmod 600 /dev/sev
setfacl -m g:sev:r /dev/sev
setfacl -m g:sev-admin:rw /dev/sev
In this instance, members of the "sev-admin" group have the ability to
perform all ioctl calls (including the ones that modify platform state).
Members of the "sev" group only have access to the ioctls that do not
modify the platform state.
This also makes opening "/dev/sev" more consistent with how file
descriptors are usually handled. By only checking for CAP_SYS_ADMIN,
the file descriptor could be opened read-only but could still execute
ioctls that modify the platform state. This patch enforces that the file
descriptor is opened with write privileges if it is going to be used to
modify the platform state.
This flexibility is completely opt-in, and if it is not desirable by
the administrator then they do not need to give anyone else access to
/dev/sev.
Signed-off-by: Connor Kuehl <ckuehl@redhat.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Bandan Das <bsd@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Explicitly free and clear misc_dev in sev_exit(). Since devm_kzalloc()
associates misc_dev with the first device that gets probed, change from
devm_kzalloc() to kzalloc() and explicitly free memory in sev_exit() as
the first device probed is not guaranteed to be the last device released.
To ensure that the variable gets properly set to NULL, remove the local
definition of misc_dev.
Fixes: 200664d523 ("crypto: ccp: Add Secure Encrypted Virtualization (SEV) command support")
Signed-off-by: John Allen <john.allen@amd.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
PSP can support both SEV and TEE interface. Therefore, move
SEV specific registers to a dedicated data structure.
TEE interface specific registers will be added in a later
patch.
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Jens Wiklander <jens.wiklander@linaro.org>
Co-developed-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Rijo Thomas <Rijo-john.Thomas@amd.com>
Acked-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The PSP (Platform Security Processor) provides support for key management
commands in Secure Encrypted Virtualization (SEV) mode, along with
software-based Trusted Execution Environment (TEE) to enable third-party
Trusted Applications.
Therefore, introduce psp-dev.c and psp-dev.h files, which can invoke
SEV (or TEE) initialization based on platform feature support.
TEE interface support will be introduced in a later patch.
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Jens Wiklander <jens.wiklander@linaro.org>
Co-developed-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Rijo Thomas <Rijo-john.Thomas@amd.com>
Acked-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This is a preliminary patch for creating a generic PSP device driver
file, which will have support for both SEV and TEE (Trusted Execution
Environment) interface.
This patch does not introduce any new functionality, but simply renames
psp-dev.c and psp-dev.h files to sev-dev.c and sev-dev.h files
respectively.
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Jens Wiklander <jens.wiklander@linaro.org>
Co-developed-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Rijo Thomas <Rijo-john.Thomas@amd.com>
Acked-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
