1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright(c) 2016-20 Intel Corporation. */
3
4 #include <stddef.h>
5 #include "defines.h"
6
7 /*
8 * Data buffer spanning two pages that will be placed first in the .data
9 * segment via the linker script. Even if not used internally the second page
10 * is needed by external test manipulating page permissions, so mark
11 * encl_buffer as "used" to make sure it is entirely preserved by the compiler.
12 */
13 static uint8_t __used __section(".data.encl_buffer") encl_buffer[8192] = { 1 };
14
15 enum sgx_enclu_function {
16 EACCEPT = 0x5,
17 EMODPE = 0x6,
18 };
19
20 static void do_encl_emodpe(void *_op)
21 {
22 struct sgx_secinfo secinfo __aligned(sizeof(struct sgx_secinfo)) = {0};
23 struct encl_op_emodpe *op = _op;
24
25 secinfo.flags = op->flags;
26
27 asm volatile(".byte 0x0f, 0x01, 0xd7"
28 : /* no outputs */
29 : "a" (EMODPE),
30 "b" (&secinfo),
31 "c" (op->epc_addr)
32 : "memory" /* read from secinfo pointer */);
33 }
34
35 static void do_encl_eaccept(void *_op)
36 {
37 struct sgx_secinfo secinfo __aligned(sizeof(struct sgx_secinfo)) = {0};
38 struct encl_op_eaccept *op = _op;
39 int rax;
40
41 secinfo.flags = op->flags;
42
43 asm volatile(".byte 0x0f, 0x01, 0xd7"
44 : "=a" (rax)
45 : "a" (EACCEPT),
46 "b" (&secinfo),
47 "c" (op->epc_addr)
48 : "memory" /* read from secinfo pointer */);
49
50 op->ret = rax;
51 }
52
53 static void *memcpy(void *dest, const void *src, size_t n)
54 {
55 size_t i;
56
57 for (i = 0; i < n; i++)
58 ((char *)dest)[i] = ((char *)src)[i];
59
60 return dest;
61 }
62
63 static void *memset(void *dest, int c, size_t n)
64 {
65 size_t i;
66
67 for (i = 0; i < n; i++)
68 ((char *)dest)[i] = c;
69
70 return dest;
71 }
72
73 static void do_encl_init_tcs_page(void *_op)
74 {
75 struct encl_op_init_tcs_page *op = _op;
76 void *tcs = (void *)op->tcs_page;
77 uint32_t val_32;
78
79 memset(tcs, 0, 16); /* STATE and FLAGS */
80 memcpy(tcs + 16, &op->ssa, 8); /* OSSA */
81 memset(tcs + 24, 0, 4); /* CSSA */
82 val_32 = 1;
83 memcpy(tcs + 28, &val_32, 4); /* NSSA */
84 memcpy(tcs + 32, &op->entry, 8); /* OENTRY */
85 memset(tcs + 40, 0, 24); /* AEP, OFSBASE, OGSBASE */
86 val_32 = 0xFFFFFFFF;
87 memcpy(tcs + 64, &val_32, 4); /* FSLIMIT */
88 memcpy(tcs + 68, &val_32, 4); /* GSLIMIT */
89 memset(tcs + 72, 0, 4024); /* Reserved */
90 }
91
92 static void do_encl_op_put_to_buf(void *op)
93 {
94 struct encl_op_put_to_buf *op2 = op;
95
96 memcpy(&encl_buffer[0], &op2->value, 8);
97 }
98
99 static void do_encl_op_get_from_buf(void *op)
100 {
101 struct encl_op_get_from_buf *op2 = op;
102
103 memcpy(&op2->value, &encl_buffer[0], 8);
104 }
105
106 static void do_encl_op_put_to_addr(void *_op)
107 {
108 struct encl_op_put_to_addr *op = _op;
109
110 memcpy((void *)op->addr, &op->value, 8);
111 }
112
113 static void do_encl_op_get_from_addr(void *_op)
114 {
115 struct encl_op_get_from_addr *op = _op;
116
117 memcpy(&op->value, (void *)op->addr, 8);
118 }
119
120 static void do_encl_op_nop(void *_op)
121 {
122
123 }
124
125 /*
126 * Symbol placed at the start of the enclave image by the linker script.
127 * Declare this extern symbol with visibility "hidden" to ensure the compiler
128 * does not access it through the GOT and generates position-independent
129 * addressing as __encl_base(%rip), so we can get the actual enclave base
130 * during runtime.
131 */
132 extern const uint8_t __attribute__((visibility("hidden"))) __encl_base;
133
134 typedef void (*encl_op_t)(void *);
135 static const encl_op_t encl_op_array[ENCL_OP_MAX] = {
136 do_encl_op_put_to_buf,
137 do_encl_op_get_from_buf,
138 do_encl_op_put_to_addr,
139 do_encl_op_get_from_addr,
140 do_encl_op_nop,
141 do_encl_eaccept,
142 do_encl_emodpe,
143 do_encl_init_tcs_page,
144 };
145
146 void encl_body(void *rdi, void *rsi)
147 {
148 struct encl_op_header *header = (struct encl_op_header *)rdi;
149 encl_op_t op;
150
151 if (header->type >= ENCL_OP_MAX)
152 return;
153
154 /*
155 * The enclave base address needs to be added, as this call site
156 * *cannot be* made rip-relative by the compiler, or fixed up by
157 * any other possible means.
158 */
159 op = ((uint64_t)&__encl_base) + encl_op_array[header->type];
160
161 (*op)(header);
162 }
163
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