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Commit | Line | Data |
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00f496c4 KC |
1 | /* |
2 | * This is for all the tests related to logic bugs (e.g. bad dereferences, | |
3 | * bad alignment, bad loops, bad locking, bad scheduling, deep stacks, and | |
4 | * lockups) along with other things that don't fit well into existing LKDTM | |
5 | * test source files. | |
6 | */ | |
00f496c4 | 7 | #include "lkdtm.h" |
6819d101 | 8 | #include <linux/list.h> |
6d2e91a6 | 9 | #include <linux/sched.h> |
e22aa9d7 KC |
10 | #include <linux/sched/signal.h> |
11 | #include <linux/uaccess.h> | |
00f496c4 | 12 | |
6819d101 KC |
13 | struct lkdtm_list { |
14 | struct list_head node; | |
15 | }; | |
16 | ||
00f496c4 KC |
17 | /* |
18 | * Make sure our attempts to over run the kernel stack doesn't trigger | |
19 | * a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we | |
20 | * recurse past the end of THREAD_SIZE by default. | |
21 | */ | |
22 | #if defined(CONFIG_FRAME_WARN) && (CONFIG_FRAME_WARN > 0) | |
23 | #define REC_STACK_SIZE (CONFIG_FRAME_WARN / 2) | |
24 | #else | |
25 | #define REC_STACK_SIZE (THREAD_SIZE / 8) | |
26 | #endif | |
27 | #define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2) | |
28 | ||
29 | static int recur_count = REC_NUM_DEFAULT; | |
30 | ||
31 | static DEFINE_SPINLOCK(lock_me_up); | |
32 | ||
33 | static int recursive_loop(int remaining) | |
34 | { | |
35 | char buf[REC_STACK_SIZE]; | |
36 | ||
37 | /* Make sure compiler does not optimize this away. */ | |
38 | memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE); | |
39 | if (!remaining) | |
40 | return 0; | |
41 | else | |
42 | return recursive_loop(remaining - 1); | |
43 | } | |
44 | ||
45 | /* If the depth is negative, use the default, otherwise keep parameter. */ | |
46 | void __init lkdtm_bugs_init(int *recur_param) | |
47 | { | |
48 | if (*recur_param < 0) | |
49 | *recur_param = recur_count; | |
50 | else | |
51 | recur_count = *recur_param; | |
52 | } | |
53 | ||
54 | void lkdtm_PANIC(void) | |
55 | { | |
56 | panic("dumptest"); | |
57 | } | |
58 | ||
59 | void lkdtm_BUG(void) | |
60 | { | |
61 | BUG(); | |
62 | } | |
63 | ||
64 | void lkdtm_WARNING(void) | |
65 | { | |
66 | WARN_ON(1); | |
67 | } | |
68 | ||
69 | void lkdtm_EXCEPTION(void) | |
70 | { | |
9e18308a | 71 | *((volatile int *) 0) = 0; |
00f496c4 KC |
72 | } |
73 | ||
74 | void lkdtm_LOOP(void) | |
75 | { | |
76 | for (;;) | |
77 | ; | |
78 | } | |
79 | ||
80 | void lkdtm_OVERFLOW(void) | |
81 | { | |
82 | (void) recursive_loop(recur_count); | |
83 | } | |
84 | ||
7a11a1d1 AB |
85 | static noinline void __lkdtm_CORRUPT_STACK(void *stack) |
86 | { | |
87 | memset(stack, 'a', 64); | |
88 | } | |
89 | ||
00f496c4 KC |
90 | noinline void lkdtm_CORRUPT_STACK(void) |
91 | { | |
92 | /* Use default char array length that triggers stack protection. */ | |
93 | char data[8]; | |
7a11a1d1 | 94 | __lkdtm_CORRUPT_STACK(&data); |
00f496c4 | 95 | |
c55d2400 | 96 | pr_info("Corrupted stack with '%16s'...\n", data); |
00f496c4 KC |
97 | } |
98 | ||
99 | void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void) | |
100 | { | |
101 | static u8 data[5] __attribute__((aligned(4))) = {1, 2, 3, 4, 5}; | |
102 | u32 *p; | |
103 | u32 val = 0x12345678; | |
104 | ||
105 | p = (u32 *)(data + 1); | |
106 | if (*p == 0) | |
107 | val = 0x87654321; | |
108 | *p = val; | |
109 | } | |
110 | ||
111 | void lkdtm_SOFTLOCKUP(void) | |
112 | { | |
113 | preempt_disable(); | |
114 | for (;;) | |
115 | cpu_relax(); | |
116 | } | |
117 | ||
118 | void lkdtm_HARDLOCKUP(void) | |
119 | { | |
120 | local_irq_disable(); | |
121 | for (;;) | |
122 | cpu_relax(); | |
123 | } | |
124 | ||
125 | void lkdtm_SPINLOCKUP(void) | |
126 | { | |
127 | /* Must be called twice to trigger. */ | |
128 | spin_lock(&lock_me_up); | |
129 | /* Let sparse know we intended to exit holding the lock. */ | |
130 | __release(&lock_me_up); | |
131 | } | |
132 | ||
133 | void lkdtm_HUNG_TASK(void) | |
134 | { | |
135 | set_current_state(TASK_UNINTERRUPTIBLE); | |
136 | schedule(); | |
137 | } | |
138 | ||
6819d101 KC |
139 | void lkdtm_CORRUPT_LIST_ADD(void) |
140 | { | |
141 | /* | |
142 | * Initially, an empty list via LIST_HEAD: | |
143 | * test_head.next = &test_head | |
144 | * test_head.prev = &test_head | |
145 | */ | |
146 | LIST_HEAD(test_head); | |
147 | struct lkdtm_list good, bad; | |
148 | void *target[2] = { }; | |
149 | void *redirection = ⌖ | |
150 | ||
151 | pr_info("attempting good list addition\n"); | |
152 | ||
153 | /* | |
154 | * Adding to the list performs these actions: | |
155 | * test_head.next->prev = &good.node | |
156 | * good.node.next = test_head.next | |
157 | * good.node.prev = test_head | |
158 | * test_head.next = good.node | |
159 | */ | |
160 | list_add(&good.node, &test_head); | |
161 | ||
162 | pr_info("attempting corrupted list addition\n"); | |
163 | /* | |
164 | * In simulating this "write what where" primitive, the "what" is | |
165 | * the address of &bad.node, and the "where" is the address held | |
166 | * by "redirection". | |
167 | */ | |
168 | test_head.next = redirection; | |
169 | list_add(&bad.node, &test_head); | |
170 | ||
171 | if (target[0] == NULL && target[1] == NULL) | |
172 | pr_err("Overwrite did not happen, but no BUG?!\n"); | |
173 | else | |
174 | pr_err("list_add() corruption not detected!\n"); | |
175 | } | |
176 | ||
177 | void lkdtm_CORRUPT_LIST_DEL(void) | |
178 | { | |
179 | LIST_HEAD(test_head); | |
180 | struct lkdtm_list item; | |
181 | void *target[2] = { }; | |
182 | void *redirection = ⌖ | |
183 | ||
184 | list_add(&item.node, &test_head); | |
185 | ||
186 | pr_info("attempting good list removal\n"); | |
187 | list_del(&item.node); | |
188 | ||
189 | pr_info("attempting corrupted list removal\n"); | |
190 | list_add(&item.node, &test_head); | |
191 | ||
192 | /* As with the list_add() test above, this corrupts "next". */ | |
193 | item.node.next = redirection; | |
194 | list_del(&item.node); | |
195 | ||
196 | if (target[0] == NULL && target[1] == NULL) | |
197 | pr_err("Overwrite did not happen, but no BUG?!\n"); | |
198 | else | |
199 | pr_err("list_del() corruption not detected!\n"); | |
200 | } | |
e22aa9d7 KC |
201 | |
202 | void lkdtm_CORRUPT_USER_DS(void) | |
203 | { | |
204 | pr_info("setting bad task size limit\n"); | |
205 | set_fs(KERNEL_DS); | |
206 | ||
207 | /* Make sure we do not keep running with a KERNEL_DS! */ | |
208 | force_sig(SIGKILL, current); | |
209 | } |