bpf: add unprivileged bpf tests

Add new tests samples/bpf/test_verifier:

unpriv: return pointer
  checks that pointer cannot be returned from the eBPF program

unpriv: add const to pointer
unpriv: add pointer to pointer
unpriv: neg pointer
  checks that pointer arithmetic is disallowed

unpriv: cmp pointer with const
unpriv: cmp pointer with pointer
  checks that comparison of pointers is disallowed
  Only one case allowed 'void *value = bpf_map_lookup_elem(..); if (value == 0) ...'

unpriv: check that printk is disallowed
  since bpf_trace_printk is not available to unprivileged

unpriv: pass pointer to helper function
  checks that pointers cannot be passed to functions that expect integers
  If function expects a pointer the verifier allows only that type of pointer.
  Like 1st argument of bpf_map_lookup_elem() must be pointer to map.
  (applies to non-root as well)

unpriv: indirectly pass pointer on stack to helper function
  checks that pointer stored into stack cannot be used as part of key
  passed into bpf_map_lookup_elem()

unpriv: mangle pointer on stack 1
unpriv: mangle pointer on stack 2
  checks that writing into stack slot that already contains a pointer
  is disallowed

unpriv: read pointer from stack in small chunks
  checks that < 8 byte read from stack slot that contains a pointer is
  disallowed

unpriv: write pointer into ctx
  checks that storing pointers into skb->fields is disallowed

unpriv: write pointer into map elem value
  checks that storing pointers into element values is disallowed
  For example:
  int bpf_prog(struct __sk_buff *skb)
  {
    u32 key = 0;
    u64 *value = bpf_map_lookup_elem(&map, &key);
    if (value)
       *value = (u64) skb;
  }
  will be rejected.

unpriv: partial copy of pointer
  checks that doing 32-bit register mov from register containing
  a pointer is disallowed

unpriv: pass pointer to tail_call
  checks that passing pointer as an index into bpf_tail_call
  is disallowed

unpriv: cmp map pointer with zero
  checks that comparing map pointer with constant is disallowed

unpriv: write into frame pointer
  checks that frame pointer is read-only (applies to root too)

unpriv: cmp of frame pointer
  checks that R10 cannot be using in comparison

unpriv: cmp of stack pointer
  checks that Rx = R10 - imm is ok, but comparing Rx is not

unpriv: obfuscate stack pointer
  checks that Rx = R10 - imm is ok, but Rx -= imm is not

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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)					\

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();
 }