lib/test_bpf: Add test to check for result of 32-bit add that overflows

BPF_ALU32 and BPF_ALU64 tests for adding two 32-bit values that results in
32-bit overflow.

Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index 7e6fb49..2fb31aa 100644 (file)
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -2443,6 +2443,22 @@ static struct bpf_test tests[] = {
                { },
                { { 0, 4294967295U } },
        },
+       {
+               "ALU_ADD_X: 2 + 4294967294 = 0",
+               .u.insns_int = {
+                       BPF_LD_IMM64(R0, 2),
+                       BPF_LD_IMM64(R1, 4294967294U),
+                       BPF_ALU32_REG(BPF_ADD, R0, R1),
+                       BPF_JMP_IMM(BPF_JEQ, R0, 0, 2),
+                       BPF_ALU32_IMM(BPF_MOV, R0, 0),
+                       BPF_EXIT_INSN(),
+                       BPF_ALU32_IMM(BPF_MOV, R0, 1),
+                       BPF_EXIT_INSN(),
+               },
+               INTERNAL,
+               { },
+               { { 0, 1 } },
+       },
        {
                "ALU64_ADD_X: 1 + 2 = 3",
                .u.insns_int = {
@@ -2467,6 +2483,23 @@ static struct bpf_test tests[] = {
                { },
                { { 0, 4294967295U } },
        },
+       {
+               "ALU64_ADD_X: 2 + 4294967294 = 4294967296",
+               .u.insns_int = {
+                       BPF_LD_IMM64(R0, 2),
+                       BPF_LD_IMM64(R1, 4294967294U),
+                       BPF_LD_IMM64(R2, 4294967296ULL),
+                       BPF_ALU64_REG(BPF_ADD, R0, R1),
+                       BPF_JMP_REG(BPF_JEQ, R0, R2, 2),
+                       BPF_MOV32_IMM(R0, 0),
+                       BPF_EXIT_INSN(),
+                       BPF_MOV32_IMM(R0, 1),
+                       BPF_EXIT_INSN(),
+               },
+               INTERNAL,
+               { },
+               { { 0, 1 } },
+       },
        /* BPF_ALU | BPF_ADD | BPF_K */
        {
                "ALU_ADD_K: 1 + 2 = 3",
@@ -2501,6 +2534,21 @@ static struct bpf_test tests[] = {
                { },
                { { 0, 4294967295U } },
        },
+       {
+               "ALU_ADD_K: 4294967294 + 2 = 0",
+               .u.insns_int = {
+                       BPF_LD_IMM64(R0, 4294967294U),
+                       BPF_ALU32_IMM(BPF_ADD, R0, 2),
+                       BPF_JMP_IMM(BPF_JEQ, R0, 0, 2),
+                       BPF_ALU32_IMM(BPF_MOV, R0, 0),
+                       BPF_EXIT_INSN(),
+                       BPF_ALU32_IMM(BPF_MOV, R0, 1),
+                       BPF_EXIT_INSN(),
+               },
+               INTERNAL,
+               { },
+               { { 0, 1 } },
+       },
        {
                "ALU_ADD_K: 0 + (-1) = 0x00000000ffffffff",
                .u.insns_int = {
@@ -2550,6 +2598,22 @@ static struct bpf_test tests[] = {
                { },
                { { 0, 2147483647 } },
        },
+       {
+               "ALU64_ADD_K: 4294967294 + 2 = 4294967296",
+               .u.insns_int = {
+                       BPF_LD_IMM64(R0, 4294967294U),
+                       BPF_LD_IMM64(R1, 4294967296ULL),
+                       BPF_ALU64_IMM(BPF_ADD, R0, 2),
+                       BPF_JMP_REG(BPF_JEQ, R0, R1, 2),
+                       BPF_ALU32_IMM(BPF_MOV, R0, 0),
+                       BPF_EXIT_INSN(),
+                       BPF_ALU32_IMM(BPF_MOV, R0, 1),
+                       BPF_EXIT_INSN(),
+               },
+               INTERNAL,
+               { },
+               { { 0, 1 } },
+       },
        {
                "ALU64_ADD_K: 2147483646 + -2147483647 = -1",
                .u.insns_int = {