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1// SPDX-License-Identifier: GPL-2.0
2#include <test_progs.h>
3
4#define MAX_INSNS 512
5#define MAX_MATCHES 24
6
7struct bpf_reg_match {
8 unsigned int line;
9 const char *match;
10};
11
12struct bpf_align_test {
13 const char *descr;
14 struct bpf_insn insns[MAX_INSNS];
15 enum {
16 UNDEF,
17 ACCEPT,
18 REJECT
19 } result;
20 enum bpf_prog_type prog_type;
21 /* Matches must be in order of increasing line */
22 struct bpf_reg_match matches[MAX_MATCHES];
23};
24
25static struct bpf_align_test tests[] = {
26 /* Four tests of known constants. These aren't staggeringly
27 * interesting since we track exact values now.
28 */
29 {
30 .descr = "mov",
31 .insns = {
32 BPF_MOV64_IMM(BPF_REG_3, 2),
33 BPF_MOV64_IMM(BPF_REG_3, 4),
34 BPF_MOV64_IMM(BPF_REG_3, 8),
35 BPF_MOV64_IMM(BPF_REG_3, 16),
36 BPF_MOV64_IMM(BPF_REG_3, 32),
37 BPF_MOV64_IMM(BPF_REG_0, 0),
38 BPF_EXIT_INSN(),
39 },
40 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
41 .matches = {
42 {0, "R1=ctx(off=0,imm=0)"},
43 {0, "R10=fp0"},
44 {0, "R3_w=2"},
45 {1, "R3_w=4"},
46 {2, "R3_w=8"},
47 {3, "R3_w=16"},
48 {4, "R3_w=32"},
49 },
50 },
51 {
52 .descr = "shift",
53 .insns = {
54 BPF_MOV64_IMM(BPF_REG_3, 1),
55 BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
56 BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
57 BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
58 BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
59 BPF_ALU64_IMM(BPF_RSH, BPF_REG_3, 4),
60 BPF_MOV64_IMM(BPF_REG_4, 32),
61 BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
62 BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
63 BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
64 BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
65 BPF_MOV64_IMM(BPF_REG_0, 0),
66 BPF_EXIT_INSN(),
67 },
68 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
69 .matches = {
70 {0, "R1=ctx(off=0,imm=0)"},
71 {0, "R10=fp0"},
72 {0, "R3_w=1"},
73 {1, "R3_w=2"},
74 {2, "R3_w=4"},
75 {3, "R3_w=8"},
76 {4, "R3_w=16"},
77 {5, "R3_w=1"},
78 {6, "R4_w=32"},
79 {7, "R4_w=16"},
80 {8, "R4_w=8"},
81 {9, "R4_w=4"},
82 {10, "R4_w=2"},
83 },
84 },
85 {
86 .descr = "addsub",
87 .insns = {
88 BPF_MOV64_IMM(BPF_REG_3, 4),
89 BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 4),
90 BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 2),
91 BPF_MOV64_IMM(BPF_REG_4, 8),
92 BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
93 BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 2),
94 BPF_MOV64_IMM(BPF_REG_0, 0),
95 BPF_EXIT_INSN(),
96 },
97 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
98 .matches = {
99 {0, "R1=ctx(off=0,imm=0)"},
100 {0, "R10=fp0"},
101 {0, "R3_w=4"},
102 {1, "R3_w=8"},
103 {2, "R3_w=10"},
104 {3, "R4_w=8"},
105 {4, "R4_w=12"},
106 {5, "R4_w=14"},
107 },
108 },
109 {
110 .descr = "mul",
111 .insns = {
112 BPF_MOV64_IMM(BPF_REG_3, 7),
113 BPF_ALU64_IMM(BPF_MUL, BPF_REG_3, 1),
114 BPF_ALU64_IMM(BPF_MUL, BPF_REG_3, 2),
115 BPF_ALU64_IMM(BPF_MUL, BPF_REG_3, 4),
116 BPF_MOV64_IMM(BPF_REG_0, 0),
117 BPF_EXIT_INSN(),
118 },
119 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
120 .matches = {
121 {0, "R1=ctx(off=0,imm=0)"},
122 {0, "R10=fp0"},
123 {0, "R3_w=7"},
124 {1, "R3_w=7"},
125 {2, "R3_w=14"},
126 {3, "R3_w=56"},
127 },
128 },
129
130 /* Tests using unknown values */
131#define PREP_PKT_POINTERS \
132 BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, \
133 offsetof(struct __sk_buff, data)), \
134 BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, \
135 offsetof(struct __sk_buff, data_end))
136
137#define LOAD_UNKNOWN(DST_REG) \
138 PREP_PKT_POINTERS, \
139 BPF_MOV64_REG(BPF_REG_0, BPF_REG_2), \
140 BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8), \
141 BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_0, 1), \
142 BPF_EXIT_INSN(), \
143 BPF_LDX_MEM(BPF_B, DST_REG, BPF_REG_2, 0)
144
145 {
146 .descr = "unknown shift",
147 .insns = {
148 LOAD_UNKNOWN(BPF_REG_3),
149 BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
150 BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
151 BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
152 BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1),
153 LOAD_UNKNOWN(BPF_REG_4),
154 BPF_ALU64_IMM(BPF_LSH, BPF_REG_4, 5),
155 BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
156 BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
157 BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
158 BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1),
159 BPF_MOV64_IMM(BPF_REG_0, 0),
160 BPF_EXIT_INSN(),
161 },
162 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
163 .matches = {
164 {6, "R0_w=pkt(off=8,r=8,imm=0)"},
165 {6, "R3_w=scalar(umax=255,var_off=(0x0; 0xff))"},
166 {7, "R3_w=scalar(umax=510,var_off=(0x0; 0x1fe))"},
167 {8, "R3_w=scalar(umax=1020,var_off=(0x0; 0x3fc))"},
168 {9, "R3_w=scalar(umax=2040,var_off=(0x0; 0x7f8))"},
169 {10, "R3_w=scalar(umax=4080,var_off=(0x0; 0xff0))"},
170 {12, "R3_w=pkt_end(off=0,imm=0)"},
171 {17, "R4_w=scalar(umax=255,var_off=(0x0; 0xff))"},
172 {18, "R4_w=scalar(umax=8160,var_off=(0x0; 0x1fe0))"},
173 {19, "R4_w=scalar(umax=4080,var_off=(0x0; 0xff0))"},
174 {20, "R4_w=scalar(umax=2040,var_off=(0x0; 0x7f8))"},
175 {21, "R4_w=scalar(umax=1020,var_off=(0x0; 0x3fc))"},
176 {22, "R4_w=scalar(umax=510,var_off=(0x0; 0x1fe))"},
177 },
178 },
179 {
180 .descr = "unknown mul",
181 .insns = {
182 LOAD_UNKNOWN(BPF_REG_3),
183 BPF_MOV64_REG(BPF_REG_4, BPF_REG_3),
184 BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 1),
185 BPF_MOV64_REG(BPF_REG_4, BPF_REG_3),
186 BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 2),
187 BPF_MOV64_REG(BPF_REG_4, BPF_REG_3),
188 BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 4),
189 BPF_MOV64_REG(BPF_REG_4, BPF_REG_3),
190 BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 8),
191 BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 2),
192 BPF_MOV64_IMM(BPF_REG_0, 0),
193 BPF_EXIT_INSN(),
194 },
195 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
196 .matches = {
197 {6, "R3_w=scalar(umax=255,var_off=(0x0; 0xff))"},
198 {7, "R4_w=scalar(id=1,umax=255,var_off=(0x0; 0xff))"},
199 {8, "R4_w=scalar(umax=255,var_off=(0x0; 0xff))"},
200 {9, "R4_w=scalar(id=1,umax=255,var_off=(0x0; 0xff))"},
201 {10, "R4_w=scalar(umax=510,var_off=(0x0; 0x1fe))"},
202 {11, "R4_w=scalar(id=1,umax=255,var_off=(0x0; 0xff))"},
203 {12, "R4_w=scalar(umax=1020,var_off=(0x0; 0x3fc))"},
204 {13, "R4_w=scalar(id=1,umax=255,var_off=(0x0; 0xff))"},
205 {14, "R4_w=scalar(umax=2040,var_off=(0x0; 0x7f8))"},
206 {15, "R4_w=scalar(umax=4080,var_off=(0x0; 0xff0))"},
207 },
208 },
209 {
210 .descr = "packet const offset",
211 .insns = {
212 PREP_PKT_POINTERS,
213 BPF_MOV64_REG(BPF_REG_5, BPF_REG_2),
214
215 BPF_MOV64_IMM(BPF_REG_0, 0),
216
217 /* Skip over ethernet header. */
218 BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 14),
219 BPF_MOV64_REG(BPF_REG_4, BPF_REG_5),
220 BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
221 BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1),
222 BPF_EXIT_INSN(),
223
224 BPF_LDX_MEM(BPF_B, BPF_REG_4, BPF_REG_5, 0),
225 BPF_LDX_MEM(BPF_B, BPF_REG_4, BPF_REG_5, 1),
226 BPF_LDX_MEM(BPF_B, BPF_REG_4, BPF_REG_5, 2),
227 BPF_LDX_MEM(BPF_B, BPF_REG_4, BPF_REG_5, 3),
228 BPF_LDX_MEM(BPF_H, BPF_REG_4, BPF_REG_5, 0),
229 BPF_LDX_MEM(BPF_H, BPF_REG_4, BPF_REG_5, 2),
230 BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_5, 0),
231
232 BPF_MOV64_IMM(BPF_REG_0, 0),
233 BPF_EXIT_INSN(),
234 },
235 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
236 .matches = {
237 {2, "R5_w=pkt(off=0,r=0,imm=0)"},
238 {4, "R5_w=pkt(off=14,r=0,imm=0)"},
239 {5, "R4_w=pkt(off=14,r=0,imm=0)"},
240 {9, "R2=pkt(off=0,r=18,imm=0)"},
241 {10, "R5=pkt(off=14,r=18,imm=0)"},
242 {10, "R4_w=scalar(umax=255,var_off=(0x0; 0xff))"},
243 {13, "R4_w=scalar(umax=65535,var_off=(0x0; 0xffff))"},
244 {14, "R4_w=scalar(umax=65535,var_off=(0x0; 0xffff))"},
245 },
246 },
247 {
248 .descr = "packet variable offset",
249 .insns = {
250 LOAD_UNKNOWN(BPF_REG_6),
251 BPF_ALU64_IMM(BPF_LSH, BPF_REG_6, 2),
252
253 /* First, add a constant to the R5 packet pointer,
254 * then a variable with a known alignment.
255 */
256 BPF_MOV64_REG(BPF_REG_5, BPF_REG_2),
257 BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 14),
258 BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6),
259 BPF_MOV64_REG(BPF_REG_4, BPF_REG_5),
260 BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
261 BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1),
262 BPF_EXIT_INSN(),
263 BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_5, 0),
264
265 /* Now, test in the other direction. Adding first
266 * the variable offset to R5, then the constant.
267 */
268 BPF_MOV64_REG(BPF_REG_5, BPF_REG_2),
269 BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6),
270 BPF_MOV64_REG(BPF_REG_4, BPF_REG_5),
271 BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 14),
272 BPF_MOV64_REG(BPF_REG_4, BPF_REG_5),
273 BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
274 BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1),
275 BPF_EXIT_INSN(),
276 BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_5, 0),
277
278 /* Test multiple accumulations of unknown values
279 * into a packet pointer.
280 */
281 BPF_MOV64_REG(BPF_REG_5, BPF_REG_2),
282 BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 14),
283 BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6),
284 BPF_MOV64_REG(BPF_REG_4, BPF_REG_5),
285 BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 4),
286 BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6),
287 BPF_MOV64_REG(BPF_REG_4, BPF_REG_5),
288 BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
289 BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1),
290 BPF_EXIT_INSN(),
291 BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_5, 0),
292
293 BPF_MOV64_IMM(BPF_REG_0, 0),
294 BPF_EXIT_INSN(),
295 },
296 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
297 .matches = {
298 /* Calculated offset in R6 has unknown value, but known
299 * alignment of 4.
300 */
301 {6, "R2_w=pkt(off=0,r=8,imm=0)"},
302 {7, "R6_w=scalar(umax=1020,var_off=(0x0; 0x3fc))"},
303 /* Offset is added to packet pointer R5, resulting in
304 * known fixed offset, and variable offset from R6.
305 */
306 {11, "R5_w=pkt(id=1,off=14,r=0,umax=1020,var_off=(0x0; 0x3fc))"},
307 /* At the time the word size load is performed from R5,
308 * it's total offset is NET_IP_ALIGN + reg->off (0) +
309 * reg->aux_off (14) which is 16. Then the variable
310 * offset is considered using reg->aux_off_align which
311 * is 4 and meets the load's requirements.
312 */
313 {15, "R4=pkt(id=1,off=18,r=18,umax=1020,var_off=(0x0; 0x3fc))"},
314 {15, "R5=pkt(id=1,off=14,r=18,umax=1020,var_off=(0x0; 0x3fc))"},
315 /* Variable offset is added to R5 packet pointer,
316 * resulting in auxiliary alignment of 4. To avoid BPF
317 * verifier's precision backtracking logging
318 * interfering we also have a no-op R4 = R5
319 * instruction to validate R5 state. We also check
320 * that R4 is what it should be in such case.
321 */
322 {18, "R4_w=pkt(id=2,off=0,r=0,umax=1020,var_off=(0x0; 0x3fc))"},
323 {18, "R5_w=pkt(id=2,off=0,r=0,umax=1020,var_off=(0x0; 0x3fc))"},
324 /* Constant offset is added to R5, resulting in
325 * reg->off of 14.
326 */
327 {19, "R5_w=pkt(id=2,off=14,r=0,umax=1020,var_off=(0x0; 0x3fc))"},
328 /* At the time the word size load is performed from R5,
329 * its total fixed offset is NET_IP_ALIGN + reg->off
330 * (14) which is 16. Then the variable offset is 4-byte
331 * aligned, so the total offset is 4-byte aligned and
332 * meets the load's requirements.
333 */
334 {24, "R4=pkt(id=2,off=18,r=18,umax=1020,var_off=(0x0; 0x3fc))"},
335 {24, "R5=pkt(id=2,off=14,r=18,umax=1020,var_off=(0x0; 0x3fc))"},
336 /* Constant offset is added to R5 packet pointer,
337 * resulting in reg->off value of 14.
338 */
339 {26, "R5_w=pkt(off=14,r=8"},
340 /* Variable offset is added to R5, resulting in a
341 * variable offset of (4n). See comment for insn #18
342 * for R4 = R5 trick.
343 */
344 {28, "R4_w=pkt(id=3,off=14,r=0,umax=1020,var_off=(0x0; 0x3fc))"},
345 {28, "R5_w=pkt(id=3,off=14,r=0,umax=1020,var_off=(0x0; 0x3fc))"},
346 /* Constant is added to R5 again, setting reg->off to 18. */
347 {29, "R5_w=pkt(id=3,off=18,r=0,umax=1020,var_off=(0x0; 0x3fc))"},
348 /* And once more we add a variable; resulting var_off
349 * is still (4n), fixed offset is not changed.
350 * Also, we create a new reg->id.
351 */
352 {31, "R4_w=pkt(id=4,off=18,r=0,umax=2040,var_off=(0x0; 0x7fc)"},
353 {31, "R5_w=pkt(id=4,off=18,r=0,umax=2040,var_off=(0x0; 0x7fc)"},
354 /* At the time the word size load is performed from R5,
355 * its total fixed offset is NET_IP_ALIGN + reg->off (18)
356 * which is 20. Then the variable offset is (4n), so
357 * the total offset is 4-byte aligned and meets the
358 * load's requirements.
359 */
360 {35, "R4=pkt(id=4,off=22,r=22,umax=2040,var_off=(0x0; 0x7fc)"},
361 {35, "R5=pkt(id=4,off=18,r=22,umax=2040,var_off=(0x0; 0x7fc)"},
362 },
363 },
364 {
365 .descr = "packet variable offset 2",
366 .insns = {
367 /* Create an unknown offset, (4n+2)-aligned */
368 LOAD_UNKNOWN(BPF_REG_6),
369 BPF_ALU64_IMM(BPF_LSH, BPF_REG_6, 2),
370 BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 14),
371 /* Add it to the packet pointer */
372 BPF_MOV64_REG(BPF_REG_5, BPF_REG_2),
373 BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6),
374 /* Check bounds and perform a read */
375 BPF_MOV64_REG(BPF_REG_4, BPF_REG_5),
376 BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
377 BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1),
378 BPF_EXIT_INSN(),
379 BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_5, 0),
380 /* Make a (4n) offset from the value we just read */
381 BPF_ALU64_IMM(BPF_AND, BPF_REG_6, 0xff),
382 BPF_ALU64_IMM(BPF_LSH, BPF_REG_6, 2),
383 /* Add it to the packet pointer */
384 BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6),
385 /* Check bounds and perform a read */
386 BPF_MOV64_REG(BPF_REG_4, BPF_REG_5),
387 BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
388 BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1),
389 BPF_EXIT_INSN(),
390 BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_5, 0),
391 BPF_MOV64_IMM(BPF_REG_0, 0),
392 BPF_EXIT_INSN(),
393 },
394 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
395 .matches = {
396 /* Calculated offset in R6 has unknown value, but known
397 * alignment of 4.
398 */
399 {6, "R2_w=pkt(off=0,r=8,imm=0)"},
400 {7, "R6_w=scalar(umax=1020,var_off=(0x0; 0x3fc))"},
401 /* Adding 14 makes R6 be (4n+2) */
402 {8, "R6_w=scalar(umin=14,umax=1034,var_off=(0x2; 0x7fc))"},
403 /* Packet pointer has (4n+2) offset */
404 {11, "R5_w=pkt(id=1,off=0,r=0,umin=14,umax=1034,var_off=(0x2; 0x7fc)"},
405 {12, "R4=pkt(id=1,off=4,r=0,umin=14,umax=1034,var_off=(0x2; 0x7fc)"},
406 /* At the time the word size load is performed from R5,
407 * its total fixed offset is NET_IP_ALIGN + reg->off (0)
408 * which is 2. Then the variable offset is (4n+2), so
409 * the total offset is 4-byte aligned and meets the
410 * load's requirements.
411 */
412 {15, "R5=pkt(id=1,off=0,r=4,umin=14,umax=1034,var_off=(0x2; 0x7fc)"},
413 /* Newly read value in R6 was shifted left by 2, so has
414 * known alignment of 4.
415 */
416 {17, "R6_w=scalar(umax=1020,var_off=(0x0; 0x3fc))"},
417 /* Added (4n) to packet pointer's (4n+2) var_off, giving
418 * another (4n+2).
419 */
420 {19, "R5_w=pkt(id=2,off=0,r=0,umin=14,umax=2054,var_off=(0x2; 0xffc)"},
421 {20, "R4=pkt(id=2,off=4,r=0,umin=14,umax=2054,var_off=(0x2; 0xffc)"},
422 /* At the time the word size load is performed from R5,
423 * its total fixed offset is NET_IP_ALIGN + reg->off (0)
424 * which is 2. Then the variable offset is (4n+2), so
425 * the total offset is 4-byte aligned and meets the
426 * load's requirements.
427 */
428 {23, "R5=pkt(id=2,off=0,r=4,umin=14,umax=2054,var_off=(0x2; 0xffc)"},
429 },
430 },
431 {
432 .descr = "dubious pointer arithmetic",
433 .insns = {
434 PREP_PKT_POINTERS,
435 BPF_MOV64_IMM(BPF_REG_0, 0),
436 /* (ptr - ptr) << 2 */
437 BPF_MOV64_REG(BPF_REG_5, BPF_REG_3),
438 BPF_ALU64_REG(BPF_SUB, BPF_REG_5, BPF_REG_2),
439 BPF_ALU64_IMM(BPF_LSH, BPF_REG_5, 2),
440 /* We have a (4n) value. Let's make a packet offset
441 * out of it. First add 14, to make it a (4n+2)
442 */
443 BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 14),
444 /* Then make sure it's nonnegative */
445 BPF_JMP_IMM(BPF_JSGE, BPF_REG_5, 0, 1),
446 BPF_EXIT_INSN(),
447 /* Add it to packet pointer */
448 BPF_MOV64_REG(BPF_REG_6, BPF_REG_2),
449 BPF_ALU64_REG(BPF_ADD, BPF_REG_6, BPF_REG_5),
450 /* Check bounds and perform a read */
451 BPF_MOV64_REG(BPF_REG_4, BPF_REG_6),
452 BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
453 BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1),
454 BPF_EXIT_INSN(),
455 BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_6, 0),
456 BPF_EXIT_INSN(),
457 },
458 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
459 .result = REJECT,
460 .matches = {
461 {3, "R5_w=pkt_end(off=0,imm=0)"},
462 /* (ptr - ptr) << 2 == unknown, (4n) */
463 {5, "R5_w=scalar(smax=9223372036854775804,umax=18446744073709551612,var_off=(0x0; 0xfffffffffffffffc)"},
464 /* (4n) + 14 == (4n+2). We blow our bounds, because
465 * the add could overflow.
466 */
467 {6, "R5_w=scalar(smin=-9223372036854775806,smax=9223372036854775806,umin=2,umax=18446744073709551614,var_off=(0x2; 0xfffffffffffffffc)"},
468 /* Checked s>=0 */
469 {9, "R5=scalar(umin=2,umax=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc)"},
470 /* packet pointer + nonnegative (4n+2) */
471 {11, "R6_w=pkt(id=1,off=0,r=0,umin=2,umax=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc)"},
472 {12, "R4_w=pkt(id=1,off=4,r=0,umin=2,umax=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc)"},
473 /* NET_IP_ALIGN + (4n+2) == (4n), alignment is fine.
474 * We checked the bounds, but it might have been able
475 * to overflow if the packet pointer started in the
476 * upper half of the address space.
477 * So we did not get a 'range' on R6, and the access
478 * attempt will fail.
479 */
480 {15, "R6_w=pkt(id=1,off=0,r=0,umin=2,umax=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc)"},
481 }
482 },
483 {
484 .descr = "variable subtraction",
485 .insns = {
486 /* Create an unknown offset, (4n+2)-aligned */
487 LOAD_UNKNOWN(BPF_REG_6),
488 BPF_MOV64_REG(BPF_REG_7, BPF_REG_6),
489 BPF_ALU64_IMM(BPF_LSH, BPF_REG_6, 2),
490 BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 14),
491 /* Create another unknown, (4n)-aligned, and subtract
492 * it from the first one
493 */
494 BPF_ALU64_IMM(BPF_LSH, BPF_REG_7, 2),
495 BPF_ALU64_REG(BPF_SUB, BPF_REG_6, BPF_REG_7),
496 /* Bounds-check the result */
497 BPF_JMP_IMM(BPF_JSGE, BPF_REG_6, 0, 1),
498 BPF_EXIT_INSN(),
499 /* Add it to the packet pointer */
500 BPF_MOV64_REG(BPF_REG_5, BPF_REG_2),
501 BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6),
502 /* Check bounds and perform a read */
503 BPF_MOV64_REG(BPF_REG_4, BPF_REG_5),
504 BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
505 BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1),
506 BPF_EXIT_INSN(),
507 BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_5, 0),
508 BPF_EXIT_INSN(),
509 },
510 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
511 .matches = {
512 /* Calculated offset in R6 has unknown value, but known
513 * alignment of 4.
514 */
515 {6, "R2_w=pkt(off=0,r=8,imm=0)"},
516 {8, "R6_w=scalar(umax=1020,var_off=(0x0; 0x3fc))"},
517 /* Adding 14 makes R6 be (4n+2) */
518 {9, "R6_w=scalar(umin=14,umax=1034,var_off=(0x2; 0x7fc))"},
519 /* New unknown value in R7 is (4n) */
520 {10, "R7_w=scalar(umax=1020,var_off=(0x0; 0x3fc))"},
521 /* Subtracting it from R6 blows our unsigned bounds */
522 {11, "R6=scalar(smin=-1006,smax=1034,umin=2,umax=18446744073709551614,var_off=(0x2; 0xfffffffffffffffc)"},
523 /* Checked s>= 0 */
524 {14, "R6=scalar(umin=2,umax=1034,var_off=(0x2; 0x7fc))"},
525 /* At the time the word size load is performed from R5,
526 * its total fixed offset is NET_IP_ALIGN + reg->off (0)
527 * which is 2. Then the variable offset is (4n+2), so
528 * the total offset is 4-byte aligned and meets the
529 * load's requirements.
530 */
531 {20, "R5=pkt(id=2,off=0,r=4,umin=2,umax=1034,var_off=(0x2; 0x7fc)"},
532
533 },
534 },
535 {
536 .descr = "pointer variable subtraction",
537 .insns = {
538 /* Create an unknown offset, (4n+2)-aligned and bounded
539 * to [14,74]
540 */
541 LOAD_UNKNOWN(BPF_REG_6),
542 BPF_MOV64_REG(BPF_REG_7, BPF_REG_6),
543 BPF_ALU64_IMM(BPF_AND, BPF_REG_6, 0xf),
544 BPF_ALU64_IMM(BPF_LSH, BPF_REG_6, 2),
545 BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 14),
546 /* Subtract it from the packet pointer */
547 BPF_MOV64_REG(BPF_REG_5, BPF_REG_2),
548 BPF_ALU64_REG(BPF_SUB, BPF_REG_5, BPF_REG_6),
549 /* Create another unknown, (4n)-aligned and >= 74.
550 * That in fact means >= 76, since 74 % 4 == 2
551 */
552 BPF_ALU64_IMM(BPF_LSH, BPF_REG_7, 2),
553 BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, 76),
554 /* Add it to the packet pointer */
555 BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_7),
556 /* Check bounds and perform a read */
557 BPF_MOV64_REG(BPF_REG_4, BPF_REG_5),
558 BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
559 BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1),
560 BPF_EXIT_INSN(),
561 BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_5, 0),
562 BPF_EXIT_INSN(),
563 },
564 .prog_type = BPF_PROG_TYPE_SCHED_CLS,
565 .matches = {
566 /* Calculated offset in R6 has unknown value, but known
567 * alignment of 4.
568 */
569 {6, "R2_w=pkt(off=0,r=8,imm=0)"},
570 {9, "R6_w=scalar(umax=60,var_off=(0x0; 0x3c))"},
571 /* Adding 14 makes R6 be (4n+2) */
572 {10, "R6_w=scalar(umin=14,umax=74,var_off=(0x2; 0x7c))"},
573 /* Subtracting from packet pointer overflows ubounds */
574 {13, "R5_w=pkt(id=2,off=0,r=8,umin=18446744073709551542,umax=18446744073709551602,var_off=(0xffffffffffffff82; 0x7c)"},
575 /* New unknown value in R7 is (4n), >= 76 */
576 {14, "R7_w=scalar(umin=76,umax=1096,var_off=(0x0; 0x7fc))"},
577 /* Adding it to packet pointer gives nice bounds again */
578 {16, "R5_w=pkt(id=3,off=0,r=0,umin=2,umax=1082,var_off=(0x2; 0xfffffffc)"},
579 /* At the time the word size load is performed from R5,
580 * its total fixed offset is NET_IP_ALIGN + reg->off (0)
581 * which is 2. Then the variable offset is (4n+2), so
582 * the total offset is 4-byte aligned and meets the
583 * load's requirements.
584 */
585 {20, "R5=pkt(id=3,off=0,r=4,umin=2,umax=1082,var_off=(0x2; 0xfffffffc)"},
586 },
587 },
588};
589
590static int probe_filter_length(const struct bpf_insn *fp)
591{
592 int len;
593
594 for (len = MAX_INSNS - 1; len > 0; --len)
595 if (fp[len].code != 0 || fp[len].imm != 0)
596 break;
597 return len + 1;
598}
599
600static char bpf_vlog[32768];
601
602static int do_test_single(struct bpf_align_test *test)
603{
604 struct bpf_insn *prog = test->insns;
605 int prog_type = test->prog_type;
606 char bpf_vlog_copy[32768];
607 LIBBPF_OPTS(bpf_prog_load_opts, opts,
608 .prog_flags = BPF_F_STRICT_ALIGNMENT,
609 .log_buf = bpf_vlog,
610 .log_size = sizeof(bpf_vlog),
611 .log_level = 2,
612 );
613 const char *line_ptr;
614 int cur_line = -1;
615 int prog_len, i;
616 int fd_prog;
617 int ret;
618
619 prog_len = probe_filter_length(prog);
620 fd_prog = bpf_prog_load(prog_type ? : BPF_PROG_TYPE_SOCKET_FILTER, NULL, "GPL",
621 prog, prog_len, &opts);
622 if (fd_prog < 0 && test->result != REJECT) {
623 printf("Failed to load program.\n");
624 printf("%s", bpf_vlog);
625 ret = 1;
626 } else if (fd_prog >= 0 && test->result == REJECT) {
627 printf("Unexpected success to load!\n");
628 printf("%s", bpf_vlog);
629 ret = 1;
630 close(fd_prog);
631 } else {
632 ret = 0;
633 /* We make a local copy so that we can strtok() it */
634 strncpy(bpf_vlog_copy, bpf_vlog, sizeof(bpf_vlog_copy));
635 line_ptr = strtok(bpf_vlog_copy, "\n");
636 for (i = 0; i < MAX_MATCHES; i++) {
637 struct bpf_reg_match m = test->matches[i];
638 int tmp;
639
640 if (!m.match)
641 break;
642 while (line_ptr) {
643 cur_line = -1;
644 sscanf(line_ptr, "%u: ", &cur_line);
645 if (cur_line == -1)
646 sscanf(line_ptr, "from %u to %u: ", &tmp, &cur_line);
647 if (cur_line == m.line)
648 break;
649 line_ptr = strtok(NULL, "\n");
650 }
651 if (!line_ptr) {
652 printf("Failed to find line %u for match: %s\n",
653 m.line, m.match);
654 ret = 1;
655 printf("%s", bpf_vlog);
656 break;
657 }
658 /* Check the next line as well in case the previous line
659 * did not have a corresponding bpf insn. Example:
660 * func#0 @0
661 * 0: R1=ctx(off=0,imm=0) R10=fp0
662 * 0: (b7) r3 = 2 ; R3_w=2
663 */
664 if (!strstr(line_ptr, m.match)) {
665 cur_line = -1;
666 line_ptr = strtok(NULL, "\n");
667 sscanf(line_ptr, "%u: ", &cur_line);
668 }
669 if (cur_line != m.line || !line_ptr ||
670 !strstr(line_ptr, m.match)) {
671 printf("Failed to find match %u: %s\n",
672 m.line, m.match);
673 ret = 1;
674 printf("%s", bpf_vlog);
675 break;
676 }
677 }
678 if (fd_prog >= 0)
679 close(fd_prog);
680 }
681 return ret;
682}
683
684void test_align(void)
685{
686 unsigned int i;
687
688 for (i = 0; i < ARRAY_SIZE(tests); i++) {
689 struct bpf_align_test *test = &tests[i];
690
691 if (!test__start_subtest(test->descr))
692 continue;
693
694 ASSERT_OK(do_test_single(test), test->descr);
695 }
696}