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Date: Tue, 22 Mar 2022 09:43:12 +0200
From: Jarkko Sakkinen <jarkko@...nel.org>
To: Shuah Khan <skhan@...uxfoundation.org>
Cc: Jarkko Sakkinen <jarkko@...nel.org>,
Reinette Chatre <reinette.chatre@...el.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Shuah Khan <shuah@...nel.org>,
linux-sgx@...r.kernel.org (open list:INTEL SGX),
linux-kselftest@...r.kernel.org (open list:KERNEL SELFTEST FRAMEWORK),
linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v2 2/2] selftests/sgx: Make TCS table relocatable
Add a PT_NOTE section with n_namesz containg "TCS" and n_descz containing
32-bit offset to the TCS table inside the enclave. This allows to place the
TCS segment freely, and thereby make the kselftest binary layout way more
robust.
Cc: Reinette Chatre <reinette.chatre@...el.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com
Signed-off-by: Jarkko Sakkinen <jarkko@...nel.org>
---
v2:
* Add RIP relative addressing fix for bootstrap as prepending patch, as
this depends on it.
* Moved TCS section as the last so that it is easy to add new TCS's,
e.g dynamically with EAUG + EMODT, behind it.
---
tools/testing/selftests/sgx/load.c | 56 ++++++++++++++-----
tools/testing/selftests/sgx/main.c | 37 +++---------
tools/testing/selftests/sgx/main.h | 2 +
tools/testing/selftests/sgx/test_encl.lds | 17 ++++--
.../selftests/sgx/test_encl_bootstrap.S | 7 +++
5 files changed, 72 insertions(+), 47 deletions(-)
diff --git a/tools/testing/selftests/sgx/load.c b/tools/testing/selftests/sgx/load.c
index 006b464c8fc9..214b9da631bd 100644
--- a/tools/testing/selftests/sgx/load.c
+++ b/tools/testing/selftests/sgx/load.c
@@ -19,6 +19,9 @@
#include "defines.h"
#include "main.h"
+const char *TCS_NOTE_NAME = "TCS";
+const unsigned long TCS_NOTE_LEN = 4;
+
void encl_delete(struct encl *encl)
{
struct encl_segment *heap_seg;
@@ -187,11 +190,31 @@ bool encl_load(const char *path, struct encl *encl, unsigned long heap_size)
encl->nr_segments = 1; /* one for the heap */
+ /* Count the loadable segments and discover the TCS array. */
for (i = 0; i < ehdr->e_phnum; i++) {
Elf64_Phdr *phdr = &phdr_tbl[i];
+ Elf64_Nhdr *note;
+ char *note_name;
- if (phdr->p_type == PT_LOAD)
+ switch (phdr->p_type) {
+ case PT_LOAD:
encl->nr_segments++;
+ break;
+
+ case PT_NOTE:
+ note = encl->bin + (phdr->p_offset & PAGE_MASK);
+ note_name = &((char *)note)[sizeof(*note)];
+
+ if (note->n_namesz == TCS_NOTE_LEN &&
+ !strncmp(note_name, TCS_NOTE_NAME, TCS_NOTE_LEN)) {
+ /* 32-bit address. */
+ encl->tcs = (struct sgx_tcs *)(unsigned long)(note->n_descsz);
+ }
+ break;
+
+ default:
+ break;
+ }
}
encl->segment_tbl = calloc(encl->nr_segments,
@@ -215,31 +238,36 @@ bool encl_load(const char *path, struct encl *encl, unsigned long heap_size)
goto err;
}
- if (j == 0 && flags != (PF_R | PF_W)) {
- fprintf(stderr,
- "TCS has invalid segment flags 0x%02x.\n",
- phdr->p_flags);
- goto err;
- }
-
if (j == 0) {
src_offset = phdr->p_offset & PAGE_MASK;
encl->src = encl->bin + src_offset;
+ }
+
+ seg->offset = (phdr->p_offset & PAGE_MASK) - src_offset;
+ seg->size = (phdr->p_filesz + PAGE_SIZE - 1) & PAGE_MASK;
+ seg->src = encl->src + seg->offset;
+ seg->measure = true;
+
+ if (seg->offset == (unsigned long)encl->tcs) {
+ if (flags != (PF_R | PF_W)) {
+ fprintf(stderr,
+ "TCS has invalid segment flags 0x%02x.\n",
+ phdr->p_flags);
+ goto err;
+ }
seg->prot = PROT_READ | PROT_WRITE;
seg->flags = SGX_PAGE_TYPE_TCS << 8;
} else {
+ if ((flags & (PF_R | PF_W | PF_X)) == (PF_R | PF_W))
+ encl->data_offset = seg->offset;
+
seg->prot = (phdr->p_flags & PF_R) ? PROT_READ : 0;
seg->prot |= (phdr->p_flags & PF_W) ? PROT_WRITE : 0;
seg->prot |= (phdr->p_flags & PF_X) ? PROT_EXEC : 0;
seg->flags = (SGX_PAGE_TYPE_REG << 8) | seg->prot;
}
- seg->offset = (phdr->p_offset & PAGE_MASK) - src_offset;
- seg->size = (phdr->p_filesz + PAGE_SIZE - 1) & PAGE_MASK;
- seg->src = encl->src + seg->offset;
- seg->measure = true;
-
j++;
}
@@ -322,5 +350,7 @@ bool encl_build(struct encl *encl)
return false;
}
+ encl->tcs = (struct sgx_tcs *)((unsigned long)encl->tcs + encl->encl_base);
+
return true;
}
diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c
index dd74fa42302e..b206548803b4 100644
--- a/tools/testing/selftests/sgx/main.c
+++ b/tools/testing/selftests/sgx/main.c
@@ -109,25 +109,6 @@ static Elf64_Sym *vdso_symtab_get(struct vdso_symtab *symtab, const char *name)
return NULL;
}
-/*
- * Return the offset in the enclave where the data segment can be found.
- * The first RW segment loaded is the TCS, skip that to get info on the
- * data segment.
- */
-static off_t encl_get_data_offset(struct encl *encl)
-{
- int i;
-
- for (i = 1; i < encl->nr_segments; i++) {
- struct encl_segment *seg = &encl->segment_tbl[i];
-
- if (seg->prot == (PROT_READ | PROT_WRITE))
- return seg->offset;
- }
-
- return -1;
-}
-
FIXTURE(enclave) {
struct encl encl;
struct sgx_enclave_run run;
@@ -248,7 +229,7 @@ TEST_F(enclave, unclobbered_vdso)
ASSERT_TRUE(setup_test_encl(ENCL_HEAP_SIZE_DEFAULT, &self->encl, _metadata));
memset(&self->run, 0, sizeof(self->run));
- self->run.tcs = self->encl.encl_base;
+ self->run.tcs = (__u64)self->encl.tcs;
put_op.header.type = ENCL_OP_PUT_TO_BUFFER;
put_op.value = MAGIC;
@@ -321,7 +302,7 @@ TEST_F(enclave, unclobbered_vdso_oversubscribed)
ASSERT_TRUE(setup_test_encl(total_mem, &self->encl, _metadata));
memset(&self->run, 0, sizeof(self->run));
- self->run.tcs = self->encl.encl_base;
+ self->run.tcs = (__u64)self->encl.tcs;
put_op.header.type = ENCL_OP_PUT_TO_BUFFER;
put_op.value = MAGIC;
@@ -350,7 +331,7 @@ TEST_F(enclave, clobbered_vdso)
ASSERT_TRUE(setup_test_encl(ENCL_HEAP_SIZE_DEFAULT, &self->encl, _metadata));
memset(&self->run, 0, sizeof(self->run));
- self->run.tcs = self->encl.encl_base;
+ self->run.tcs = (__u64)self->encl.tcs;
put_op.header.type = ENCL_OP_PUT_TO_BUFFER;
put_op.value = MAGIC;
@@ -386,7 +367,7 @@ TEST_F(enclave, clobbered_vdso_and_user_function)
ASSERT_TRUE(setup_test_encl(ENCL_HEAP_SIZE_DEFAULT, &self->encl, _metadata));
memset(&self->run, 0, sizeof(self->run));
- self->run.tcs = self->encl.encl_base;
+ self->run.tcs = (__u64)self->encl.tcs;
self->run.user_handler = (__u64)test_handler;
self->run.user_data = 0xdeadbeef;
@@ -419,7 +400,7 @@ TEST_F(enclave, tcs_entry)
ASSERT_TRUE(setup_test_encl(ENCL_HEAP_SIZE_DEFAULT, &self->encl, _metadata));
memset(&self->run, 0, sizeof(self->run));
- self->run.tcs = self->encl.encl_base;
+ self->run.tcs = (__u64)self->encl.tcs;
op.type = ENCL_OP_NOP;
@@ -431,7 +412,7 @@ TEST_F(enclave, tcs_entry)
EXPECT_EQ(self->run.exception_addr, 0);
/* Move to the next TCS. */
- self->run.tcs = self->encl.encl_base + PAGE_SIZE;
+ self->run.tcs = (__u64)self->encl.tcs + PAGE_SIZE;
EXPECT_EQ(ENCL_CALL(&op, &self->run, true), 0);
@@ -464,11 +445,9 @@ TEST_F(enclave, pte_permissions)
ASSERT_TRUE(setup_test_encl(ENCL_HEAP_SIZE_DEFAULT, &self->encl, _metadata));
memset(&self->run, 0, sizeof(self->run));
- self->run.tcs = self->encl.encl_base;
+ self->run.tcs = (__u64)self->encl.tcs;
- data_start = self->encl.encl_base +
- encl_get_data_offset(&self->encl) +
- PAGE_SIZE;
+ data_start = self->encl.encl_base + self->encl.data_offset + PAGE_SIZE;
/*
* Sanity check to ensure it is possible to write to page that will
diff --git a/tools/testing/selftests/sgx/main.h b/tools/testing/selftests/sgx/main.h
index b45c52ec7ab3..bccb263be8d9 100644
--- a/tools/testing/selftests/sgx/main.h
+++ b/tools/testing/selftests/sgx/main.h
@@ -29,6 +29,8 @@ struct encl {
struct encl_segment *segment_tbl;
struct sgx_secs secs;
struct sgx_sigstruct sigstruct;
+ struct sgx_tcs *tcs;
+ unsigned long data_offset;
};
extern unsigned char sign_key[];
diff --git a/tools/testing/selftests/sgx/test_encl.lds b/tools/testing/selftests/sgx/test_encl.lds
index a1ec64f7d91f..d76df884d8a4 100644
--- a/tools/testing/selftests/sgx/test_encl.lds
+++ b/tools/testing/selftests/sgx/test_encl.lds
@@ -2,17 +2,15 @@ OUTPUT_FORMAT(elf64-x86-64)
PHDRS
{
- tcs PT_LOAD;
text PT_LOAD;
data PT_LOAD;
+ tcs PT_LOAD;
+ note PT_NOTE;
}
SECTIONS
{
. = 0;
- .tcs : {
- *(.tcs*)
- } : tcs
. = ALIGN(4096);
.text : {
@@ -24,11 +22,20 @@ SECTIONS
.data : {
*(.data*)
+ . = ALIGN(4096);
} : data
+ .tcs : {
+ *(.tcs*)
+ } : tcs
+
+ .note : {
+ *(.note.tcs*)
+ } : note
+
/DISCARD/ : {
*(.comment*)
- *(.note*)
+ *(.note.gnu.*)
*(.debug*)
*(.eh_frame*)
}
diff --git a/tools/testing/selftests/sgx/test_encl_bootstrap.S b/tools/testing/selftests/sgx/test_encl_bootstrap.S
index 1c1b5c6c4ffe..912b21537532 100644
--- a/tools/testing/selftests/sgx/test_encl_bootstrap.S
+++ b/tools/testing/selftests/sgx/test_encl_bootstrap.S
@@ -10,6 +10,7 @@
.section ".tcs", "aw"
.balign 4096
+encl_tcs:
.fill 1, 8, 0 # STATE (set by CPU)
.fill 1, 8, 0 # FLAGS
.quad encl_ssa_tcs1 # OSSA
@@ -90,3 +91,9 @@ encl_stack:
.balign 4096
# Stack of TCS #2
.space 4096
+
+ .section ".note.tcs", "", @progbits
+ .long 4
+ .long encl_tcs
+ .long 0
+ .string "TCS"
--
2.35.1
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