| Age | Commit message (Collapse) | Author | Files | Lines |
|---|
|
As the selftest enclave is *not* intended for production, simplify the
code by not initializing CPU configuration registers as expected by the
ABI on enclave entry or cleansing caller-save registers on enclave exit.
Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lore.kernel.org/all/da0cfb1e-e347-f7f2-ac72-aec0ee0d867d@intel.com/
Link: https://lore.kernel.org/all/20231005153854.25566-14-jo.vanbulck%40cs.kuleuven.be
|
|
The current combination of -static and -fPIC creates a static executable
with position-dependent addresses for global variables. Use -static-pie
and -fPIE to create a proper static position independent executable that
can be loaded at any address without a dynamic linker.
When building the original "lea (encl_stack)(%rbx), %rax" assembly code
with -static-pie -fPIE, the linker complains about a relocation it cannot
resolve:
/usr/local/bin/ld: /tmp/cchIWyfG.o: relocation R_X86_64_32S against
`.data' can not be used when making a PIE object; recompile with -fPIE
collect2: error: ld returned 1 exit status
Thus, since only RIP-relative addressing is legit for local symbols, use
"encl_stack(%rip)" and declare an explicit "__encl_base" symbol at the
start of the linker script to be able to calculate the stack address
relative to the current TCS in the enclave assembly entry code.
Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/all/f9c24d89-ed72-7d9e-c650-050d722c6b04@cs.kuleuven.be/
Link: https://lore.kernel.org/all/20231005153854.25566-8-jo.vanbulck%40cs.kuleuven.be
|
|
Remove redundant push/pop pair that stores and restores the enclave base
address in the test enclave, as it is never used after the pop and can
anyway be easily retrieved via the __encl_base symbol.
Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/all/20231005153854.25566-7-jo.vanbulck%40cs.kuleuven.be
|
|
The test enclave (test_encl.elf) is built with two initialized
Thread Control Structures (TCS) included in the binary. Both TCS are
initialized with the same entry point, encl_entry, that correctly
computes the absolute address of the stack based on the stack of each
TCS that is also built into the binary.
A new TCS can be added dynamically to the enclave and requires to be
initialized with an entry point used to enter the enclave. Since the
existing entry point, encl_entry, assumes that the TCS and its stack
exists at particular offsets within the binary it is not able to handle
a dynamically added TCS and its stack.
Introduce a new entry point, encl_dyn_entry, that initializes the
absolute address of that thread's stack to the address immediately
preceding the TCS itself. It is now possible to dynamically add a
contiguous memory region to the enclave with the new stack preceding
the new TCS. With the new TCS initialized with encl_dyn_entry as entry
point the absolute address of the stack is computed correctly on entry.
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lkml.kernel.org/r/93e9c420dedf5f773ba6965c18245bc7d62aca83.1652137848.git.reinette.chatre@intel.com
|
|
Each thread executing in an enclave is associated with a Thread Control
Structure (TCS). The test enclave contains two hardcoded TCS. Each TCS
contains meta-data used by the hardware to save and restore thread specific
information when entering/exiting the enclave.
The two TCS structures within the test enclave share their SSA (State Save
Area) resulting in the threads clobbering each other's data. Fix this by
providing each TCS their own SSA area.
Additionally, there is an 8K stack space and its address is
computed from the enclave entry point which is correctly done for
TCS #1 that starts on the first address inside the enclave but
results in out of bounds memory when entering as TCS #2. Split 8K
stack space into two separate pages with offset symbol between to ensure
the current enclave entry calculation can continue to be used for both
threads.
While using the enclave with multiple threads requires these fixes the
impact is not apparent because every test up to this point enters the
enclave from the first TCS.
More detail about the stack fix:
-------------------------------
Before this change the test enclave (test_encl) looks as follows:
.tcs (2 pages):
(page 1) TCS #1
(page 2) TCS #2
.text (1 page)
One page of code
.data (5 pages)
(page 1) encl_buffer
(page 2) encl_buffer
(page 3) SSA
(page 4 and 5) STACK
encl_stack:
As shown above there is a symbol, encl_stack, that points to the end of the
.data segment (pointing to the end of page 5 in .data) which is also the
end of the enclave.
The enclave entry code computes the stack address by adding encl_stack to
the pointer to the TCS that entered the enclave. When entering at TCS #1
the stack is computed correctly but when entering at TCS #2 the stack
pointer would point to one page beyond the end of the enclave and a #PF
would result when TCS #2 attempts to enter the enclave.
The fix involves moving the encl_stack symbol between the two stack pages.
Doing so enables the stack address computation in the entry code to compute
the correct stack address for each TCS.
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/a49dc0d85401db788a0a3f0d795e848abf3b1f44.1636997631.git.reinette.chatre@intel.com
|
|
Add a selftest for SGX. It is a trivial test where a simple enclave
copies one 64-bit word of memory between two memory locations,
but ensures that all SGX hardware and software infrastructure is
functioning.
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Cc: linux-kselftest@vger.kernel.org
Link: https://lkml.kernel.org/r/20201112220135.165028-21-jarkko@kernel.org
|
