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-rw-r--r--arch/arm64/net/bpf_jit_comp.c20
-rw-r--r--kernel/bpf/core.c4
-rw-r--r--kernel/bpf/verifier.c64
-rw-r--r--net/core/filter.c4
-rw-r--r--tools/testing/selftests/bpf/test_verifier.c152
5 files changed, 219 insertions, 25 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index ba38d403abb2..bb32f7f6dd0f 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -148,7 +148,8 @@ static inline int epilogue_offset(const struct jit_ctx *ctx)
/* Stack must be multiples of 16B */
#define STACK_ALIGN(sz) (((sz) + 15) & ~15)
-#define PROLOGUE_OFFSET 8
+/* Tail call offset to jump into */
+#define PROLOGUE_OFFSET 7
static int build_prologue(struct jit_ctx *ctx)
{
@@ -200,19 +201,19 @@ static int build_prologue(struct jit_ctx *ctx)
/* Initialize tail_call_cnt */
emit(A64_MOVZ(1, tcc, 0, 0), ctx);
- /* 4 byte extra for skb_copy_bits buffer */
- ctx->stack_size = prog->aux->stack_depth + 4;
- ctx->stack_size = STACK_ALIGN(ctx->stack_size);
-
- /* Set up function call stack */
- emit(A64_SUB_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
-
cur_offset = ctx->idx - idx0;
if (cur_offset != PROLOGUE_OFFSET) {
pr_err_once("PROLOGUE_OFFSET = %d, expected %d!\n",
cur_offset, PROLOGUE_OFFSET);
return -1;
}
+
+ /* 4 byte extra for skb_copy_bits buffer */
+ ctx->stack_size = prog->aux->stack_depth + 4;
+ ctx->stack_size = STACK_ALIGN(ctx->stack_size);
+
+ /* Set up function call stack */
+ emit(A64_SUB_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
return 0;
}
@@ -260,11 +261,12 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx)
emit(A64_LDR64(prg, tmp, prg), ctx);
emit(A64_CBZ(1, prg, jmp_offset), ctx);
- /* goto *(prog->bpf_func + prologue_size); */
+ /* goto *(prog->bpf_func + prologue_offset); */
off = offsetof(struct bpf_prog, bpf_func);
emit_a64_mov_i64(tmp, off, ctx);
emit(A64_LDR64(tmp, prg, tmp), ctx);
emit(A64_ADD_I(1, tmp, tmp, sizeof(u32) * PROLOGUE_OFFSET), ctx);
+ emit(A64_ADD_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);
emit(A64_BR(tmp), ctx);
/* out: */
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 51ec2dda7f08..7949e8b8f94e 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -956,7 +956,7 @@ select_insn:
DST = tmp;
CONT;
ALU_MOD_X:
- if (unlikely(SRC == 0))
+ if (unlikely((u32)SRC == 0))
return 0;
tmp = (u32) DST;
DST = do_div(tmp, (u32) SRC);
@@ -975,7 +975,7 @@ select_insn:
DST = div64_u64(DST, SRC);
CONT;
ALU_DIV_X:
- if (unlikely(SRC == 0))
+ if (unlikely((u32)SRC == 0))
return 0;
tmp = (u32) DST;
do_div(tmp, (u32) SRC);
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 20eb04fd155e..13551e623501 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -978,6 +978,13 @@ static bool is_pointer_value(struct bpf_verifier_env *env, int regno)
return __is_pointer_value(env->allow_ptr_leaks, cur_regs(env) + regno);
}
+static bool is_ctx_reg(struct bpf_verifier_env *env, int regno)
+{
+ const struct bpf_reg_state *reg = cur_regs(env) + regno;
+
+ return reg->type == PTR_TO_CTX;
+}
+
static int check_pkt_ptr_alignment(struct bpf_verifier_env *env,
const struct bpf_reg_state *reg,
int off, int size, bool strict)
@@ -1258,6 +1265,12 @@ static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_ins
return -EACCES;
}
+ if (is_ctx_reg(env, insn->dst_reg)) {
+ verbose(env, "BPF_XADD stores into R%d context is not allowed\n",
+ insn->dst_reg);
+ return -EACCES;
+ }
+
/* check whether atomic_add can read the memory */
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
BPF_SIZE(insn->code), BPF_READ, -1);
@@ -1882,17 +1895,13 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
dst_reg = &regs[dst];
- if (WARN_ON_ONCE(known && (smin_val != smax_val))) {
- print_verifier_state(env, env->cur_state);
- verbose(env,
- "verifier internal error: known but bad sbounds\n");
- return -EINVAL;
- }
- if (WARN_ON_ONCE(known && (umin_val != umax_val))) {
- print_verifier_state(env, env->cur_state);
- verbose(env,
- "verifier internal error: known but bad ubounds\n");
- return -EINVAL;
+ if ((known && (smin_val != smax_val || umin_val != umax_val)) ||
+ smin_val > smax_val || umin_val > umax_val) {
+ /* Taint dst register if offset had invalid bounds derived from
+ * e.g. dead branches.
+ */
+ __mark_reg_unknown(dst_reg);
+ return 0;
}
if (BPF_CLASS(insn->code) != BPF_ALU64) {
@@ -2084,6 +2093,15 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
src_known = tnum_is_const(src_reg.var_off);
dst_known = tnum_is_const(dst_reg->var_off);
+ if ((src_known && (smin_val != smax_val || umin_val != umax_val)) ||
+ smin_val > smax_val || umin_val > umax_val) {
+ /* Taint dst register if offset had invalid bounds derived from
+ * e.g. dead branches.
+ */
+ __mark_reg_unknown(dst_reg);
+ return 0;
+ }
+
if (!src_known &&
opcode != BPF_ADD && opcode != BPF_SUB && opcode != BPF_AND) {
__mark_reg_unknown(dst_reg);
@@ -3993,6 +4011,12 @@ static int do_check(struct bpf_verifier_env *env)
if (err)
return err;
+ if (is_ctx_reg(env, insn->dst_reg)) {
+ verbose(env, "BPF_ST stores into R%d context is not allowed\n",
+ insn->dst_reg);
+ return -EACCES;
+ }
+
/* check that memory (dst_reg + off) is writeable */
err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
BPF_SIZE(insn->code), BPF_WRITE,
@@ -4445,6 +4469,24 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
int i, cnt, delta = 0;
for (i = 0; i < insn_cnt; i++, insn++) {
+ if (insn->code == (BPF_ALU | BPF_MOD | BPF_X) ||
+ insn->code == (BPF_ALU | BPF_DIV | BPF_X)) {
+ /* due to JIT bugs clear upper 32-bits of src register
+ * before div/mod operation
+ */
+ insn_buf[0] = BPF_MOV32_REG(insn->src_reg, insn->src_reg);
+ insn_buf[1] = *insn;
+ cnt = 2;
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
+
if (insn->code != (BPF_JMP | BPF_CALL))
continue;
diff --git a/net/core/filter.c b/net/core/filter.c
index d339ef170df6..1c0eb436671f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -458,6 +458,10 @@ do_pass:
convert_bpf_extensions(fp, &insn))
break;
+ if (fp->code == (BPF_ALU | BPF_DIV | BPF_X) ||
+ fp->code == (BPF_ALU | BPF_MOD | BPF_X))
+ *insn++ = BPF_MOV32_REG(BPF_REG_X, BPF_REG_X);
+
*insn = BPF_RAW_INSN(fp->code, BPF_REG_A, BPF_REG_X, 0, fp->k);
break;
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 6bafa5456568..5ed4175c4ff8 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -2593,6 +2593,29 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
+ "context stores via ST",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_ST_MEM(BPF_DW, BPF_REG_1, offsetof(struct __sk_buff, mark), 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "BPF_ST stores into R1 context is not allowed",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ },
+ {
+ "context stores via XADD",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_W, BPF_REG_1,
+ BPF_REG_0, offsetof(struct __sk_buff, mark), 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "BPF_XADD stores into R1 context is not allowed",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ },
+ {
"direct packet access: test1",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
@@ -4312,7 +4335,8 @@ static struct bpf_test tests[] = {
.fixup_map1 = { 2 },
.errstr_unpriv = "R2 leaks addr into mem",
.result_unpriv = REJECT,
- .result = ACCEPT,
+ .result = REJECT,
+ .errstr = "BPF_XADD stores into R1 context is not allowed",
},
{
"leak pointer into ctx 2",
@@ -4326,7 +4350,8 @@ static struct bpf_test tests[] = {
},
.errstr_unpriv = "R10 leaks addr into mem",
.result_unpriv = REJECT,
- .result = ACCEPT,
+ .result = REJECT,
+ .errstr = "BPF_XADD stores into R1 context is not allowed",
},
{
"leak pointer into ctx 3",
@@ -6707,7 +6732,7 @@ static struct bpf_test tests[] = {
BPF_JMP_IMM(BPF_JA, 0, 0, -7),
},
.fixup_map1 = { 4 },
- .errstr = "unbounded min value",
+ .errstr = "R0 invalid mem access 'inv'",
.result = REJECT,
},
{
@@ -8609,6 +8634,127 @@ static struct bpf_test tests[] = {
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
+ "check deducing bounds from const, 1",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 1, 0),
+ BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
+ BPF_EXIT_INSN(),
+ },
+ .result = REJECT,
+ .errstr = "R0 tried to subtract pointer from scalar",
+ },
+ {
+ "check deducing bounds from const, 2",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 1, 1),
+ BPF_EXIT_INSN(),
+ BPF_JMP_IMM(BPF_JSLE, BPF_REG_0, 1, 1),
+ BPF_EXIT_INSN(),
+ BPF_ALU64_REG(BPF_SUB, BPF_REG_1, BPF_REG_0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ },
+ {
+ "check deducing bounds from const, 3",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_JMP_IMM(BPF_JSLE, BPF_REG_0, 0, 0),
+ BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
+ BPF_EXIT_INSN(),
+ },
+ .result = REJECT,
+ .errstr = "R0 tried to subtract pointer from scalar",
+ },
+ {
+ "check deducing bounds from const, 4",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_JMP_IMM(BPF_JSLE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_ALU64_REG(BPF_SUB, BPF_REG_1, BPF_REG_0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ },
+ {
+ "check deducing bounds from const, 5",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 0, 1),
+ BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
+ BPF_EXIT_INSN(),
+ },
+ .result = REJECT,
+ .errstr = "R0 tried to subtract pointer from scalar",
+ },
+ {
+ "check deducing bounds from const, 6",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
+ BPF_EXIT_INSN(),
+ },
+ .result = REJECT,
+ .errstr = "R0 tried to subtract pointer from scalar",
+ },
+ {
+ "check deducing bounds from const, 7",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, ~0),
+ BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 0, 0),
+ BPF_ALU64_REG(BPF_SUB, BPF_REG_1, BPF_REG_0),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct __sk_buff, mark)),
+ BPF_EXIT_INSN(),
+ },
+ .result = REJECT,
+ .errstr = "dereference of modified ctx ptr",
+ },
+ {
+ "check deducing bounds from const, 8",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, ~0),
+ BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 0, 1),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_0),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct __sk_buff, mark)),
+ BPF_EXIT_INSN(),
+ },
+ .result = REJECT,
+ .errstr = "dereference of modified ctx ptr",
+ },
+ {
+ "check deducing bounds from const, 9",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_JMP_IMM(BPF_JSGE, BPF_REG_0, 0, 0),
+ BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
+ BPF_EXIT_INSN(),
+ },
+ .result = REJECT,
+ .errstr = "R0 tried to subtract pointer from scalar",
+ },
+ {
+ "check deducing bounds from const, 10",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_JMP_IMM(BPF_JSLE, BPF_REG_0, 0, 0),
+ /* Marks reg as unknown. */
+ BPF_ALU64_IMM(BPF_NEG, BPF_REG_0, 0),
+ BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_1),
+ BPF_EXIT_INSN(),
+ },
+ .result = REJECT,
+ .errstr = "math between ctx pointer and register with unbounded min value is not allowed",
+ },
+ {
"bpf_exit with invalid return code. test1",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, 0),
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