diff options
Diffstat (limited to 'tools/testing/selftests/bpf/test_align.c')
| -rw-r--r-- | tools/testing/selftests/bpf/test_align.c | 719 |
1 files changed, 719 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/test_align.c b/tools/testing/selftests/bpf/test_align.c new file mode 100644 index 000000000..3c789d03b --- /dev/null +++ b/tools/testing/selftests/bpf/test_align.c @@ -0,0 +1,719 @@ +#include <asm/types.h> +#include <linux/types.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <errno.h> +#include <string.h> +#include <stddef.h> +#include <stdbool.h> + +#include <linux/unistd.h> +#include <linux/filter.h> +#include <linux/bpf_perf_event.h> +#include <linux/bpf.h> + +#include <bpf/bpf.h> + +#include "../../../include/linux/filter.h" +#include "bpf_rlimit.h" +#include "bpf_util.h" + +#define MAX_INSNS 512 +#define MAX_MATCHES 16 + +struct bpf_reg_match { + unsigned int line; + const char *match; +}; + +struct bpf_align_test { + const char *descr; + struct bpf_insn insns[MAX_INSNS]; + enum { + UNDEF, + ACCEPT, + REJECT + } result; + enum bpf_prog_type prog_type; + /* Matches must be in order of increasing line */ + struct bpf_reg_match matches[MAX_MATCHES]; +}; + +static struct bpf_align_test tests[] = { + /* Four tests of known constants. These aren't staggeringly + * interesting since we track exact values now. + */ + { + .descr = "mov", + .insns = { + BPF_MOV64_IMM(BPF_REG_3, 2), + BPF_MOV64_IMM(BPF_REG_3, 4), + BPF_MOV64_IMM(BPF_REG_3, 8), + BPF_MOV64_IMM(BPF_REG_3, 16), + BPF_MOV64_IMM(BPF_REG_3, 32), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .matches = { + {1, "R1=ctx(id=0,off=0,imm=0)"}, + {1, "R10=fp0"}, + {1, "R3_w=inv2"}, + {2, "R3_w=inv4"}, + {3, "R3_w=inv8"}, + {4, "R3_w=inv16"}, + {5, "R3_w=inv32"}, + }, + }, + { + .descr = "shift", + .insns = { + BPF_MOV64_IMM(BPF_REG_3, 1), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1), + BPF_ALU64_IMM(BPF_RSH, BPF_REG_3, 4), + BPF_MOV64_IMM(BPF_REG_4, 32), + BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1), + BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1), + BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1), + BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .matches = { + {1, "R1=ctx(id=0,off=0,imm=0)"}, + {1, "R10=fp0"}, + {1, "R3_w=inv1"}, + {2, "R3_w=inv2"}, + {3, "R3_w=inv4"}, + {4, "R3_w=inv8"}, + {5, "R3_w=inv16"}, + {6, "R3_w=inv1"}, + {7, "R4_w=inv32"}, + {8, "R4_w=inv16"}, + {9, "R4_w=inv8"}, + {10, "R4_w=inv4"}, + {11, "R4_w=inv2"}, + }, + }, + { + .descr = "addsub", + .insns = { + BPF_MOV64_IMM(BPF_REG_3, 4), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 4), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 2), + BPF_MOV64_IMM(BPF_REG_4, 8), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 2), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .matches = { + {1, "R1=ctx(id=0,off=0,imm=0)"}, + {1, "R10=fp0"}, + {1, "R3_w=inv4"}, + {2, "R3_w=inv8"}, + {3, "R3_w=inv10"}, + {4, "R4_w=inv8"}, + {5, "R4_w=inv12"}, + {6, "R4_w=inv14"}, + }, + }, + { + .descr = "mul", + .insns = { + BPF_MOV64_IMM(BPF_REG_3, 7), + BPF_ALU64_IMM(BPF_MUL, BPF_REG_3, 1), + BPF_ALU64_IMM(BPF_MUL, BPF_REG_3, 2), + BPF_ALU64_IMM(BPF_MUL, BPF_REG_3, 4), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .matches = { + {1, "R1=ctx(id=0,off=0,imm=0)"}, + {1, "R10=fp0"}, + {1, "R3_w=inv7"}, + {2, "R3_w=inv7"}, + {3, "R3_w=inv14"}, + {4, "R3_w=inv56"}, + }, + }, + + /* Tests using unknown values */ +#define PREP_PKT_POINTERS \ + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, \ + offsetof(struct __sk_buff, data)), \ + BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, \ + offsetof(struct __sk_buff, data_end)) + +#define LOAD_UNKNOWN(DST_REG) \ + PREP_PKT_POINTERS, \ + BPF_MOV64_REG(BPF_REG_0, BPF_REG_2), \ + BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8), \ + BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_0, 1), \ + BPF_EXIT_INSN(), \ + BPF_LDX_MEM(BPF_B, DST_REG, BPF_REG_2, 0) + + { + .descr = "unknown shift", + .insns = { + LOAD_UNKNOWN(BPF_REG_3), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_3, 1), + LOAD_UNKNOWN(BPF_REG_4), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_4, 5), + BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1), + BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1), + BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1), + BPF_ALU64_IMM(BPF_RSH, BPF_REG_4, 1), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .matches = { + {7, "R0=pkt(id=0,off=8,r=8,imm=0)"}, + {7, "R3_w=inv(id=0,umax_value=255,var_off=(0x0; 0xff))"}, + {8, "R3_w=inv(id=0,umax_value=510,var_off=(0x0; 0x1fe))"}, + {9, "R3_w=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, + {10, "R3_w=inv(id=0,umax_value=2040,var_off=(0x0; 0x7f8))"}, + {11, "R3_w=inv(id=0,umax_value=4080,var_off=(0x0; 0xff0))"}, + {18, "R3=pkt_end(id=0,off=0,imm=0)"}, + {18, "R4_w=inv(id=0,umax_value=255,var_off=(0x0; 0xff))"}, + {19, "R4_w=inv(id=0,umax_value=8160,var_off=(0x0; 0x1fe0))"}, + {20, "R4_w=inv(id=0,umax_value=4080,var_off=(0x0; 0xff0))"}, + {21, "R4_w=inv(id=0,umax_value=2040,var_off=(0x0; 0x7f8))"}, + {22, "R4_w=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, + {23, "R4_w=inv(id=0,umax_value=510,var_off=(0x0; 0x1fe))"}, + }, + }, + { + .descr = "unknown mul", + .insns = { + LOAD_UNKNOWN(BPF_REG_3), + BPF_MOV64_REG(BPF_REG_4, BPF_REG_3), + BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 1), + BPF_MOV64_REG(BPF_REG_4, BPF_REG_3), + BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 2), + BPF_MOV64_REG(BPF_REG_4, BPF_REG_3), + BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 4), + BPF_MOV64_REG(BPF_REG_4, BPF_REG_3), + BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 8), + BPF_ALU64_IMM(BPF_MUL, BPF_REG_4, 2), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .matches = { + {7, "R3_w=inv(id=0,umax_value=255,var_off=(0x0; 0xff))"}, + {8, "R4_w=inv(id=0,umax_value=255,var_off=(0x0; 0xff))"}, + {9, "R4_w=inv(id=0,umax_value=255,var_off=(0x0; 0xff))"}, + {10, "R4_w=inv(id=0,umax_value=255,var_off=(0x0; 0xff))"}, + {11, "R4_w=inv(id=0,umax_value=510,var_off=(0x0; 0x1fe))"}, + {12, "R4_w=inv(id=0,umax_value=255,var_off=(0x0; 0xff))"}, + {13, "R4_w=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, + {14, "R4_w=inv(id=0,umax_value=255,var_off=(0x0; 0xff))"}, + {15, "R4_w=inv(id=0,umax_value=2040,var_off=(0x0; 0x7f8))"}, + {16, "R4_w=inv(id=0,umax_value=4080,var_off=(0x0; 0xff0))"}, + }, + }, + { + .descr = "packet const offset", + .insns = { + PREP_PKT_POINTERS, + BPF_MOV64_REG(BPF_REG_5, BPF_REG_2), + + BPF_MOV64_IMM(BPF_REG_0, 0), + + /* Skip over ethernet header. */ + BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 14), + BPF_MOV64_REG(BPF_REG_4, BPF_REG_5), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4), + BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1), + BPF_EXIT_INSN(), + + BPF_LDX_MEM(BPF_B, BPF_REG_4, BPF_REG_5, 0), + BPF_LDX_MEM(BPF_B, BPF_REG_4, BPF_REG_5, 1), + BPF_LDX_MEM(BPF_B, BPF_REG_4, BPF_REG_5, 2), + BPF_LDX_MEM(BPF_B, BPF_REG_4, BPF_REG_5, 3), + BPF_LDX_MEM(BPF_H, BPF_REG_4, BPF_REG_5, 0), + BPF_LDX_MEM(BPF_H, BPF_REG_4, BPF_REG_5, 2), + BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_5, 0), + + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .matches = { + {4, "R5_w=pkt(id=0,off=0,r=0,imm=0)"}, + {5, "R5_w=pkt(id=0,off=14,r=0,imm=0)"}, + {6, "R4_w=pkt(id=0,off=14,r=0,imm=0)"}, + {10, "R2=pkt(id=0,off=0,r=18,imm=0)"}, + {10, "R5=pkt(id=0,off=14,r=18,imm=0)"}, + {10, "R4_w=inv(id=0,umax_value=255,var_off=(0x0; 0xff))"}, + {14, "R4_w=inv(id=0,umax_value=65535,var_off=(0x0; 0xffff))"}, + {15, "R4_w=inv(id=0,umax_value=65535,var_off=(0x0; 0xffff))"}, + }, + }, + { + .descr = "packet variable offset", + .insns = { + LOAD_UNKNOWN(BPF_REG_6), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_6, 2), + + /* First, add a constant to the R5 packet pointer, + * then a variable with a known alignment. + */ + BPF_MOV64_REG(BPF_REG_5, BPF_REG_2), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 14), + BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6), + BPF_MOV64_REG(BPF_REG_4, BPF_REG_5), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4), + BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1), + BPF_EXIT_INSN(), + BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_5, 0), + + /* Now, test in the other direction. Adding first + * the variable offset to R5, then the constant. + */ + BPF_MOV64_REG(BPF_REG_5, BPF_REG_2), + BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 14), + BPF_MOV64_REG(BPF_REG_4, BPF_REG_5), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4), + BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1), + BPF_EXIT_INSN(), + BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_5, 0), + + /* Test multiple accumulations of unknown values + * into a packet pointer. + */ + BPF_MOV64_REG(BPF_REG_5, BPF_REG_2), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 14), + BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 4), + BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6), + BPF_MOV64_REG(BPF_REG_4, BPF_REG_5), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4), + BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1), + BPF_EXIT_INSN(), + BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_5, 0), + + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .matches = { + /* Calculated offset in R6 has unknown value, but known + * alignment of 4. + */ + {8, "R2=pkt(id=0,off=0,r=8,imm=0)"}, + {8, "R6_w=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, + /* Offset is added to packet pointer R5, resulting in + * known fixed offset, and variable offset from R6. + */ + {11, "R5_w=pkt(id=1,off=14,r=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, + /* At the time the word size load is performed from R5, + * it's total offset is NET_IP_ALIGN + reg->off (0) + + * reg->aux_off (14) which is 16. Then the variable + * offset is considered using reg->aux_off_align which + * is 4 and meets the load's requirements. + */ + {15, "R4=pkt(id=1,off=18,r=18,umax_value=1020,var_off=(0x0; 0x3fc))"}, + {15, "R5=pkt(id=1,off=14,r=18,umax_value=1020,var_off=(0x0; 0x3fc))"}, + /* Variable offset is added to R5 packet pointer, + * resulting in auxiliary alignment of 4. + */ + {18, "R5_w=pkt(id=2,off=0,r=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, + /* Constant offset is added to R5, resulting in + * reg->off of 14. + */ + {19, "R5_w=pkt(id=2,off=14,r=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, + /* At the time the word size load is performed from R5, + * its total fixed offset is NET_IP_ALIGN + reg->off + * (14) which is 16. Then the variable offset is 4-byte + * aligned, so the total offset is 4-byte aligned and + * meets the load's requirements. + */ + {23, "R4=pkt(id=2,off=18,r=18,umax_value=1020,var_off=(0x0; 0x3fc))"}, + {23, "R5=pkt(id=2,off=14,r=18,umax_value=1020,var_off=(0x0; 0x3fc))"}, + /* Constant offset is added to R5 packet pointer, + * resulting in reg->off value of 14. + */ + {26, "R5_w=pkt(id=0,off=14,r=8"}, + /* Variable offset is added to R5, resulting in a + * variable offset of (4n). + */ + {27, "R5_w=pkt(id=3,off=14,r=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, + /* Constant is added to R5 again, setting reg->off to 18. */ + {28, "R5_w=pkt(id=3,off=18,r=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, + /* And once more we add a variable; resulting var_off + * is still (4n), fixed offset is not changed. + * Also, we create a new reg->id. + */ + {29, "R5_w=pkt(id=4,off=18,r=0,umax_value=2040,var_off=(0x0; 0x7fc))"}, + /* At the time the word size load is performed from R5, + * its total fixed offset is NET_IP_ALIGN + reg->off (18) + * which is 20. Then the variable offset is (4n), so + * the total offset is 4-byte aligned and meets the + * load's requirements. + */ + {33, "R4=pkt(id=4,off=22,r=22,umax_value=2040,var_off=(0x0; 0x7fc))"}, + {33, "R5=pkt(id=4,off=18,r=22,umax_value=2040,var_off=(0x0; 0x7fc))"}, + }, + }, + { + .descr = "packet variable offset 2", + .insns = { + /* Create an unknown offset, (4n+2)-aligned */ + LOAD_UNKNOWN(BPF_REG_6), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_6, 2), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 14), + /* Add it to the packet pointer */ + BPF_MOV64_REG(BPF_REG_5, BPF_REG_2), + BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6), + /* Check bounds and perform a read */ + BPF_MOV64_REG(BPF_REG_4, BPF_REG_5), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4), + BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1), + BPF_EXIT_INSN(), + BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_5, 0), + /* Make a (4n) offset from the value we just read */ + BPF_ALU64_IMM(BPF_AND, BPF_REG_6, 0xff), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_6, 2), + /* Add it to the packet pointer */ + BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6), + /* Check bounds and perform a read */ + BPF_MOV64_REG(BPF_REG_4, BPF_REG_5), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4), + BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1), + BPF_EXIT_INSN(), + BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_5, 0), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .matches = { + /* Calculated offset in R6 has unknown value, but known + * alignment of 4. + */ + {8, "R2=pkt(id=0,off=0,r=8,imm=0)"}, + {8, "R6_w=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, + /* Adding 14 makes R6 be (4n+2) */ + {9, "R6_w=inv(id=0,umin_value=14,umax_value=1034,var_off=(0x2; 0x7fc))"}, + /* Packet pointer has (4n+2) offset */ + {11, "R5_w=pkt(id=1,off=0,r=0,umin_value=14,umax_value=1034,var_off=(0x2; 0x7fc))"}, + {13, "R4=pkt(id=1,off=4,r=0,umin_value=14,umax_value=1034,var_off=(0x2; 0x7fc))"}, + /* At the time the word size load is performed from R5, + * its total fixed offset is NET_IP_ALIGN + reg->off (0) + * which is 2. Then the variable offset is (4n+2), so + * the total offset is 4-byte aligned and meets the + * load's requirements. + */ + {15, "R5=pkt(id=1,off=0,r=4,umin_value=14,umax_value=1034,var_off=(0x2; 0x7fc))"}, + /* Newly read value in R6 was shifted left by 2, so has + * known alignment of 4. + */ + {18, "R6_w=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, + /* Added (4n) to packet pointer's (4n+2) var_off, giving + * another (4n+2). + */ + {19, "R5_w=pkt(id=2,off=0,r=0,umin_value=14,umax_value=2054,var_off=(0x2; 0xffc))"}, + {21, "R4=pkt(id=2,off=4,r=0,umin_value=14,umax_value=2054,var_off=(0x2; 0xffc))"}, + /* At the time the word size load is performed from R5, + * its total fixed offset is NET_IP_ALIGN + reg->off (0) + * which is 2. Then the variable offset is (4n+2), so + * the total offset is 4-byte aligned and meets the + * load's requirements. + */ + {23, "R5=pkt(id=2,off=0,r=4,umin_value=14,umax_value=2054,var_off=(0x2; 0xffc))"}, + }, + }, + { + .descr = "dubious pointer arithmetic", + .insns = { + PREP_PKT_POINTERS, + BPF_MOV64_IMM(BPF_REG_0, 0), + /* (ptr - ptr) << 2 */ + BPF_MOV64_REG(BPF_REG_5, BPF_REG_3), + BPF_ALU64_REG(BPF_SUB, BPF_REG_5, BPF_REG_2), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_5, 2), + /* We have a (4n) value. Let's make a packet offset + * out of it. First add 14, to make it a (4n+2) + */ + BPF_ALU64_IMM(BPF_ADD, BPF_REG_5, 14), + /* Then make sure it's nonnegative */ + BPF_JMP_IMM(BPF_JSGE, BPF_REG_5, 0, 1), + BPF_EXIT_INSN(), + /* Add it to packet pointer */ + BPF_MOV64_REG(BPF_REG_6, BPF_REG_2), + BPF_ALU64_REG(BPF_ADD, BPF_REG_6, BPF_REG_5), + /* Check bounds and perform a read */ + BPF_MOV64_REG(BPF_REG_4, BPF_REG_6), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4), + BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1), + BPF_EXIT_INSN(), + BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_6, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = REJECT, + .matches = { + {4, "R5_w=pkt_end(id=0,off=0,imm=0)"}, + /* (ptr - ptr) << 2 == unknown, (4n) */ + {6, "R5_w=inv(id=0,smax_value=9223372036854775804,umax_value=18446744073709551612,var_off=(0x0; 0xfffffffffffffffc))"}, + /* (4n) + 14 == (4n+2). We blow our bounds, because + * the add could overflow. + */ + {7, "R5=inv(id=0,var_off=(0x2; 0xfffffffffffffffc))"}, + /* Checked s>=0 */ + {9, "R5=inv(id=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"}, + /* packet pointer + nonnegative (4n+2) */ + {11, "R6_w=pkt(id=1,off=0,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"}, + {13, "R4=pkt(id=1,off=4,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"}, + /* NET_IP_ALIGN + (4n+2) == (4n), alignment is fine. + * We checked the bounds, but it might have been able + * to overflow if the packet pointer started in the + * upper half of the address space. + * So we did not get a 'range' on R6, and the access + * attempt will fail. + */ + {15, "R6=pkt(id=1,off=0,r=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"}, + } + }, + { + .descr = "variable subtraction", + .insns = { + /* Create an unknown offset, (4n+2)-aligned */ + LOAD_UNKNOWN(BPF_REG_6), + BPF_MOV64_REG(BPF_REG_7, BPF_REG_6), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_6, 2), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 14), + /* Create another unknown, (4n)-aligned, and subtract + * it from the first one + */ + BPF_ALU64_IMM(BPF_LSH, BPF_REG_7, 2), + BPF_ALU64_REG(BPF_SUB, BPF_REG_6, BPF_REG_7), + /* Bounds-check the result */ + BPF_JMP_IMM(BPF_JSGE, BPF_REG_6, 0, 1), + BPF_EXIT_INSN(), + /* Add it to the packet pointer */ + BPF_MOV64_REG(BPF_REG_5, BPF_REG_2), + BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6), + /* Check bounds and perform a read */ + BPF_MOV64_REG(BPF_REG_4, BPF_REG_5), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4), + BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1), + BPF_EXIT_INSN(), + BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_5, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .matches = { + /* Calculated offset in R6 has unknown value, but known + * alignment of 4. + */ + {7, "R2=pkt(id=0,off=0,r=8,imm=0)"}, + {9, "R6_w=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, + /* Adding 14 makes R6 be (4n+2) */ + {10, "R6_w=inv(id=0,umin_value=14,umax_value=1034,var_off=(0x2; 0x7fc))"}, + /* New unknown value in R7 is (4n) */ + {11, "R7_w=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"}, + /* Subtracting it from R6 blows our unsigned bounds */ + {12, "R6=inv(id=0,smin_value=-1006,smax_value=1034,var_off=(0x2; 0xfffffffffffffffc))"}, + /* Checked s>= 0 */ + {14, "R6=inv(id=0,umin_value=2,umax_value=1034,var_off=(0x2; 0x7fc))"}, + /* At the time the word size load is performed from R5, + * its total fixed offset is NET_IP_ALIGN + reg->off (0) + * which is 2. Then the variable offset is (4n+2), so + * the total offset is 4-byte aligned and meets the + * load's requirements. + */ + {20, "R5=pkt(id=1,off=0,r=4,umin_value=2,umax_value=1034,var_off=(0x2; 0x7fc))"}, + }, + }, + { + .descr = "pointer variable subtraction", + .insns = { + /* Create an unknown offset, (4n+2)-aligned and bounded + * to [14,74] + */ + LOAD_UNKNOWN(BPF_REG_6), + BPF_MOV64_REG(BPF_REG_7, BPF_REG_6), + BPF_ALU64_IMM(BPF_AND, BPF_REG_6, 0xf), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_6, 2), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 14), + /* Subtract it from the packet pointer */ + BPF_MOV64_REG(BPF_REG_5, BPF_REG_2), + BPF_ALU64_REG(BPF_SUB, BPF_REG_5, BPF_REG_6), + /* Create another unknown, (4n)-aligned and >= 74. + * That in fact means >= 76, since 74 % 4 == 2 + */ + BPF_ALU64_IMM(BPF_LSH, BPF_REG_7, 2), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, 76), + /* Add it to the packet pointer */ + BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_7), + /* Check bounds and perform a read */ + BPF_MOV64_REG(BPF_REG_4, BPF_REG_5), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4), + BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1), + BPF_EXIT_INSN(), + BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_5, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .matches = { + /* Calculated offset in R6 has unknown value, but known + * alignment of 4. + */ + {7, "R2=pkt(id=0,off=0,r=8,imm=0)"}, + {10, "R6_w=inv(id=0,umax_value=60,var_off=(0x0; 0x3c))"}, + /* Adding 14 makes R6 be (4n+2) */ + {11, "R6_w=inv(id=0,umin_value=14,umax_value=74,var_off=(0x2; 0x7c))"}, + /* Subtracting from packet pointer overflows ubounds */ + {13, "R5_w=pkt(id=1,off=0,r=8,umin_value=18446744073709551542,umax_value=18446744073709551602,var_off=(0xffffffffffffff82; 0x7c))"}, + /* New unknown value in R7 is (4n), >= 76 */ + {15, "R7_w=inv(id=0,umin_value=76,umax_value=1096,var_off=(0x0; 0x7fc))"}, + /* Adding it to packet pointer gives nice bounds again */ + {16, "R5_w=pkt(id=2,off=0,r=0,umin_value=2,umax_value=1082,var_off=(0x2; 0x7fc))"}, + /* At the time the word size load is performed from R5, + * its total fixed offset is NET_IP_ALIGN + reg->off (0) + * which is 2. Then the variable offset is (4n+2), so + * the total offset is 4-byte aligned and meets the + * load's requirements. + */ + {20, "R5=pkt(id=2,off=0,r=4,umin_value=2,umax_value=1082,var_off=(0x2; 0x7fc))"}, + }, + }, +}; + +static int probe_filter_length(const struct bpf_insn *fp) +{ + int len; + + for (len = MAX_INSNS - 1; len > 0; --len) + if (fp[len].code != 0 || fp[len].imm != 0) + break; + return len + 1; +} + +static char bpf_vlog[32768]; + +static int do_test_single(struct bpf_align_test *test) +{ + struct bpf_insn *prog = test->insns; + int prog_type = test->prog_type; + char bpf_vlog_copy[32768]; + const char *line_ptr; + int cur_line = -1; + int prog_len, i; + int fd_prog; + int ret; + + prog_len = probe_filter_length(prog); + fd_prog = bpf_verify_program(prog_type ? : BPF_PROG_TYPE_SOCKET_FILTER, + prog, prog_len, BPF_F_STRICT_ALIGNMENT, + "GPL", 0, bpf_vlog, sizeof(bpf_vlog), 2); + if (fd_prog < 0 && test->result != REJECT) { + printf("Failed to load program.\n"); + printf("%s", bpf_vlog); + ret = 1; + } else if (fd_prog >= 0 && test->result == REJECT) { + printf("Unexpected success to load!\n"); + printf("%s", bpf_vlog); + ret = 1; + close(fd_prog); + } else { + ret = 0; + /* We make a local copy so that we can strtok() it */ + strncpy(bpf_vlog_copy, bpf_vlog, sizeof(bpf_vlog_copy)); + line_ptr = strtok(bpf_vlog_copy, "\n"); + for (i = 0; i < MAX_MATCHES; i++) { + struct bpf_reg_match m = test->matches[i]; + + if (!m.match) + break; + while (line_ptr) { + cur_line = -1; + sscanf(line_ptr, "%u: ", &cur_line); + if (cur_line == m.line) + break; + line_ptr = strtok(NULL, "\n"); + } + if (!line_ptr) { + printf("Failed to find line %u for match: %s\n", + m.line, m.match); + ret = 1; + printf("%s", bpf_vlog); + break; + } + if (!strstr(line_ptr, m.match)) { + printf("Failed to find match %u: %s\n", + m.line, m.match); + ret = 1; + printf("%s", bpf_vlog); + break; + } + } + if (fd_prog >= 0) + close(fd_prog); + } + return ret; +} + +static int do_test(unsigned int from, unsigned int to) +{ + int all_pass = 0; + int all_fail = 0; + unsigned int i; + + for (i = from; i < to; i++) { + struct bpf_align_test *test = &tests[i]; + int fail; + + printf("Test %3d: %s ... ", + i, test->descr); + fail = do_test_single(test); + if (fail) { + all_fail++; + printf("FAIL\n"); + } else { + all_pass++; + printf("PASS\n"); + } + } + printf("Results: %d pass %d fail\n", + all_pass, all_fail); + return all_fail ? EXIT_FAILURE : EXIT_SUCCESS; +} + +int main(int argc, char **argv) +{ + unsigned int from = 0, to = ARRAY_SIZE(tests); + + if (argc == 3) { + unsigned int l = atoi(argv[argc - 2]); + unsigned int u = atoi(argv[argc - 1]); + + if (l < to && u < to) { + from = l; + to = u + 1; + } + } else if (argc == 2) { + unsigned int t = atoi(argv[argc - 1]); + + if (t < to) { + from = t; + to = t + 1; + } + } + return do_test(from, to); +} |