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-rw-r--r--samples/bpf/libbpf.h8
-rw-r--r--samples/bpf/test_verifier.c357
2 files changed, 355 insertions, 10 deletions
diff --git a/samples/bpf/libbpf.h b/samples/bpf/libbpf.h
index 7235e29..b7f63c70 100644
--- a/samples/bpf/libbpf.h
+++ b/samples/bpf/libbpf.h
@@ -64,6 +64,14 @@ extern char bpf_log_buf[LOG_BUF_SIZE];
.off = 0, \
.imm = 0 })
+#define BPF_MOV32_REG(DST, SRC) \
+ ((struct bpf_insn) { \
+ .code = BPF_ALU | BPF_MOV | BPF_X, \
+ .dst_reg = DST, \
+ .src_reg = SRC, \
+ .off = 0, \
+ .imm = 0 })
+
/* Short form of mov, dst_reg = imm32 */
#define BPF_MOV64_IMM(DST, IMM) \
diff --git a/samples/bpf/test_verifier.c b/samples/bpf/test_verifier.c
index ee0f110..563c507 100644
--- a/samples/bpf/test_verifier.c
+++ b/samples/bpf/test_verifier.c
@@ -15,20 +15,27 @@
#include <string.h>
#include <linux/filter.h>
#include <stddef.h>
+#include <stdbool.h>
+#include <sys/resource.h>
#include "libbpf.h"
#define MAX_INSNS 512
#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
+#define MAX_FIXUPS 8
+
struct bpf_test {
const char *descr;
struct bpf_insn insns[MAX_INSNS];
- int fixup[32];
+ int fixup[MAX_FIXUPS];
+ int prog_array_fixup[MAX_FIXUPS];
const char *errstr;
+ const char *errstr_unpriv;
enum {
+ UNDEF,
ACCEPT,
REJECT
- } result;
+ } result, result_unpriv;
enum bpf_prog_type prog_type;
};
@@ -96,6 +103,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.errstr = "invalid BPF_LD_IMM insn",
+ .errstr_unpriv = "R1 pointer comparison",
.result = REJECT,
},
{
@@ -109,6 +117,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.errstr = "invalid BPF_LD_IMM insn",
+ .errstr_unpriv = "R1 pointer comparison",
.result = REJECT,
},
{
@@ -219,6 +228,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.errstr = "R0 !read_ok",
+ .errstr_unpriv = "R1 pointer comparison",
.result = REJECT,
},
{
@@ -294,7 +304,9 @@ static struct bpf_test tests[] = {
BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
BPF_EXIT_INSN(),
},
+ .errstr_unpriv = "R0 leaks addr",
.result = ACCEPT,
+ .result_unpriv = REJECT,
},
{
"check corrupted spill/fill",
@@ -310,6 +322,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
+ .errstr_unpriv = "attempt to corrupt spilled",
.errstr = "corrupted spill",
.result = REJECT,
},
@@ -473,6 +486,7 @@ static struct bpf_test tests[] = {
},
.fixup = {3},
.errstr = "R0 invalid mem access",
+ .errstr_unpriv = "R0 leaks addr",
.result = REJECT,
},
{
@@ -495,6 +509,8 @@ static struct bpf_test tests[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
+ .errstr_unpriv = "R1 pointer comparison",
+ .result_unpriv = REJECT,
.result = ACCEPT,
},
{
@@ -521,6 +537,8 @@ static struct bpf_test tests[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
+ .errstr_unpriv = "R1 pointer comparison",
+ .result_unpriv = REJECT,
.result = ACCEPT,
},
{
@@ -555,6 +573,8 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup = {24},
+ .errstr_unpriv = "R1 pointer comparison",
+ .result_unpriv = REJECT,
.result = ACCEPT,
},
{
@@ -603,6 +623,8 @@ static struct bpf_test tests[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
+ .errstr_unpriv = "R1 pointer comparison",
+ .result_unpriv = REJECT,
.result = ACCEPT,
},
{
@@ -642,6 +664,8 @@ static struct bpf_test tests[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
+ .errstr_unpriv = "R1 pointer comparison",
+ .result_unpriv = REJECT,
.result = ACCEPT,
},
{
@@ -699,6 +723,7 @@ static struct bpf_test tests[] = {
},
.fixup = {4},
.errstr = "different pointers",
+ .errstr_unpriv = "R1 pointer comparison",
.result = REJECT,
},
{
@@ -720,6 +745,7 @@ static struct bpf_test tests[] = {
},
.fixup = {6},
.errstr = "different pointers",
+ .errstr_unpriv = "R1 pointer comparison",
.result = REJECT,
},
{
@@ -742,6 +768,7 @@ static struct bpf_test tests[] = {
},
.fixup = {7},
.errstr = "different pointers",
+ .errstr_unpriv = "R1 pointer comparison",
.result = REJECT,
},
{
@@ -752,6 +779,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.errstr = "invalid bpf_context access",
+ .errstr_unpriv = "R1 leaks addr",
.result = REJECT,
},
{
@@ -762,6 +790,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.errstr = "invalid bpf_context access",
+ .errstr_unpriv = "R1 leaks addr",
.result = REJECT,
},
{
@@ -772,16 +801,18 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.errstr = "invalid bpf_context access",
+ .errstr_unpriv = "R1 leaks addr",
.result = REJECT,
},
{
"check out of range skb->cb access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
- offsetof(struct __sk_buff, cb[60])),
+ offsetof(struct __sk_buff, cb[0]) + 256),
BPF_EXIT_INSN(),
},
.errstr = "invalid bpf_context access",
+ .errstr_unpriv = "",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_SCHED_ACT,
},
@@ -803,6 +834,8 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.result = ACCEPT,
+ .errstr_unpriv = "R1 leaks addr",
+ .result_unpriv = REJECT,
},
{
"write skb fields from tc_cls_act prog",
@@ -819,6 +852,8 @@ static struct bpf_test tests[] = {
offsetof(struct __sk_buff, cb[3])),
BPF_EXIT_INSN(),
},
+ .errstr_unpriv = "",
+ .result_unpriv = REJECT,
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
@@ -881,6 +916,270 @@ static struct bpf_test tests[] = {
.result = REJECT,
.errstr = "invalid stack off=0 size=8",
},
+ {
+ "unpriv: return pointer",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_10),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .result_unpriv = REJECT,
+ .errstr_unpriv = "R0 leaks addr",
+ },
+ {
+ "unpriv: add const to pointer",
+ .insns = {
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .result_unpriv = REJECT,
+ .errstr_unpriv = "R1 pointer arithmetic",
+ },
+ {
+ "unpriv: add pointer to pointer",
+ .insns = {
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_10),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .result_unpriv = REJECT,
+ .errstr_unpriv = "R1 pointer arithmetic",
+ },
+ {
+ "unpriv: neg pointer",
+ .insns = {
+ BPF_ALU64_IMM(BPF_NEG, BPF_REG_1, 0),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .result_unpriv = REJECT,
+ .errstr_unpriv = "R1 pointer arithmetic",
+ },
+ {
+ "unpriv: cmp pointer with const",
+ .insns = {
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 0),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .result_unpriv = REJECT,
+ .errstr_unpriv = "R1 pointer comparison",
+ },
+ {
+ "unpriv: cmp pointer with pointer",
+ .insns = {
+ BPF_JMP_REG(BPF_JEQ, BPF_REG_1, BPF_REG_10, 0),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .result_unpriv = REJECT,
+ .errstr_unpriv = "R10 pointer comparison",
+ },
+ {
+ "unpriv: check that printk is disallowed",
+ .insns = {
+ BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+ BPF_MOV64_IMM(BPF_REG_2, 8),
+ BPF_MOV64_REG(BPF_REG_3, BPF_REG_1),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_trace_printk),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr_unpriv = "unknown func 6",
+ .result_unpriv = REJECT,
+ .result = ACCEPT,
+ },
+ {
+ "unpriv: pass pointer to helper function",
+ .insns = {
+ BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_MOV64_REG(BPF_REG_3, BPF_REG_2),
+ BPF_MOV64_REG(BPF_REG_4, BPF_REG_2),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_update_elem),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup = {3},
+ .errstr_unpriv = "R4 leaks addr",
+ .result_unpriv = REJECT,
+ .result = ACCEPT,
+ },
+ {
+ "unpriv: indirectly pass pointer on stack to helper function",
+ .insns = {
+ BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_10, -8),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup = {3},
+ .errstr = "invalid indirect read from stack off -8+0 size 8",
+ .result = REJECT,
+ },
+ {
+ "unpriv: mangle pointer on stack 1",
+ .insns = {
+ BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_10, -8),
+ BPF_ST_MEM(BPF_W, BPF_REG_10, -8, 0),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr_unpriv = "attempt to corrupt spilled",
+ .result_unpriv = REJECT,
+ .result = ACCEPT,
+ },
+ {
+ "unpriv: mangle pointer on stack 2",
+ .insns = {
+ BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_10, -8),
+ BPF_ST_MEM(BPF_B, BPF_REG_10, -1, 0),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr_unpriv = "attempt to corrupt spilled",
+ .result_unpriv = REJECT,
+ .result = ACCEPT,
+ },
+ {
+ "unpriv: read pointer from stack in small chunks",
+ .insns = {
+ BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_10, -8),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_10, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid size",
+ .result = REJECT,
+ },
+ {
+ "unpriv: write pointer into ctx",
+ .insns = {
+ BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, 0),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr_unpriv = "R1 leaks addr",
+ .result_unpriv = REJECT,
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ },
+ {
+ "unpriv: write pointer into map elem value",
+ .insns = {
+ BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
+ BPF_STX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup = {3},
+ .errstr_unpriv = "R0 leaks addr",
+ .result_unpriv = REJECT,
+ .result = ACCEPT,
+ },
+ {
+ "unpriv: partial copy of pointer",
+ .insns = {
+ BPF_MOV32_REG(BPF_REG_1, BPF_REG_10),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr_unpriv = "R10 partial copy",
+ .result_unpriv = REJECT,
+ .result = ACCEPT,
+ },
+ {
+ "unpriv: pass pointer to tail_call",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_3, BPF_REG_1),
+ BPF_LD_MAP_FD(BPF_REG_2, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_tail_call),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .prog_array_fixup = {1},
+ .errstr_unpriv = "R3 leaks addr into helper",
+ .result_unpriv = REJECT,
+ .result = ACCEPT,
+ },
+ {
+ "unpriv: cmp map pointer with zero",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_1, 0),
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 0),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup = {1},
+ .errstr_unpriv = "R1 pointer comparison",
+ .result_unpriv = REJECT,
+ .result = ACCEPT,
+ },
+ {
+ "unpriv: write into frame pointer",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_10, BPF_REG_1),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "frame pointer is read only",
+ .result = REJECT,
+ },
+ {
+ "unpriv: cmp of frame pointer",
+ .insns = {
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_10, 0, 0),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr_unpriv = "R10 pointer comparison",
+ .result_unpriv = REJECT,
+ .result = ACCEPT,
+ },
+ {
+ "unpriv: cmp of stack pointer",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_2, 0, 0),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr_unpriv = "R2 pointer comparison",
+ .result_unpriv = REJECT,
+ .result = ACCEPT,
+ },
+ {
+ "unpriv: obfuscate stack pointer",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr_unpriv = "R2 pointer arithmetic",
+ .result_unpriv = REJECT,
+ .result = ACCEPT,
+ },
};
static int probe_filter_length(struct bpf_insn *fp)
@@ -896,13 +1195,24 @@ static int probe_filter_length(struct bpf_insn *fp)
static int create_map(void)
{
- long long key, value = 0;
int map_fd;
- map_fd = bpf_create_map(BPF_MAP_TYPE_HASH, sizeof(key), sizeof(value), 1024);
- if (map_fd < 0) {
+ map_fd = bpf_create_map(BPF_MAP_TYPE_HASH,
+ sizeof(long long), sizeof(long long), 1024);
+ if (map_fd < 0)
printf("failed to create map '%s'\n", strerror(errno));
- }
+
+ return map_fd;
+}
+
+static int create_prog_array(void)
+{
+ int map_fd;
+
+ map_fd = bpf_create_map(BPF_MAP_TYPE_PROG_ARRAY,
+ sizeof(int), sizeof(int), 4);
+ if (map_fd < 0)
+ printf("failed to create prog_array '%s'\n", strerror(errno));
return map_fd;
}
@@ -910,13 +1220,17 @@ static int create_map(void)
static int test(void)
{
int prog_fd, i, pass_cnt = 0, err_cnt = 0;
+ bool unpriv = geteuid() != 0;
for (i = 0; i < ARRAY_SIZE(tests); i++) {
struct bpf_insn *prog = tests[i].insns;
int prog_type = tests[i].prog_type;
int prog_len = probe_filter_length(prog);
int *fixup = tests[i].fixup;
- int map_fd = -1;
+ int *prog_array_fixup = tests[i].prog_array_fixup;
+ int expected_result;
+ const char *expected_errstr;
+ int map_fd = -1, prog_array_fd = -1;
if (*fixup) {
map_fd = create_map();
@@ -926,13 +1240,31 @@ static int test(void)
fixup++;
} while (*fixup);
}
+ if (*prog_array_fixup) {
+ prog_array_fd = create_prog_array();
+
+ do {
+ prog[*prog_array_fixup].imm = prog_array_fd;
+ prog_array_fixup++;
+ } while (*prog_array_fixup);
+ }
printf("#%d %s ", i, tests[i].descr);
prog_fd = bpf_prog_load(prog_type ?: BPF_PROG_TYPE_SOCKET_FILTER,
prog, prog_len * sizeof(struct bpf_insn),
"GPL", 0);
- if (tests[i].result == ACCEPT) {
+ if (unpriv && tests[i].result_unpriv != UNDEF)
+ expected_result = tests[i].result_unpriv;
+ else
+ expected_result = tests[i].result;
+
+ if (unpriv && tests[i].errstr_unpriv)
+ expected_errstr = tests[i].errstr_unpriv;
+ else
+ expected_errstr = tests[i].errstr;
+
+ if (expected_result == ACCEPT) {
if (prog_fd < 0) {
printf("FAIL\nfailed to load prog '%s'\n",
strerror(errno));
@@ -947,7 +1279,7 @@ static int test(void)
err_cnt++;
goto fail;
}
- if (strstr(bpf_log_buf, tests[i].errstr) == 0) {
+ if (strstr(bpf_log_buf, expected_errstr) == 0) {
printf("FAIL\nunexpected error message: %s",
bpf_log_buf);
err_cnt++;
@@ -960,6 +1292,8 @@ static int test(void)
fail:
if (map_fd >= 0)
close(map_fd);
+ if (prog_array_fd >= 0)
+ close(prog_array_fd);
close(prog_fd);
}
@@ -970,5 +1304,8 @@ fail:
int main(void)
{
+ struct rlimit r = {1 << 20, 1 << 20};
+
+ setrlimit(RLIMIT_MEMLOCK, &r);
return test();
}
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