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authorDaniel Borkmann <daniel@iogearbox.net>2017-12-21 02:15:42 +0100
committerDaniel Borkmann <daniel@iogearbox.net>2017-12-21 02:15:42 +0100
commit3db9128fcf02dcaafa3860a69a8a55d5529b6e30 (patch)
tree117e4805d7777db771898351ebdc71994371d9e3
parent19c832ed9b8f7b49fa5eeef06b4338af5fe5c1dc (diff)
parent2255f8d520b0a318fc6d387d0940854b2f522a7f (diff)
Merge branch 'bpf-verifier-sec-fixes'
Alexei Starovoitov says: ==================== This patch set addresses a set of security vulnerabilities in bpf verifier logic discovered by Jann Horn. All of the patches are candidates for 4.14 stable. ==================== Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
-rw-r--r--include/linux/bpf_verifier.h4
-rw-r--r--kernel/bpf/verifier.c175
-rw-r--r--tools/testing/selftests/bpf/test_verifier.c549
3 files changed, 661 insertions, 67 deletions
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index c561b986bab0..1632bb13ad8a 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -15,11 +15,11 @@
* In practice this is far bigger than any realistic pointer offset; this limit
* ensures that umax_value + (int)off + (int)size cannot overflow a u64.
*/
-#define BPF_MAX_VAR_OFF (1ULL << 31)
+#define BPF_MAX_VAR_OFF (1 << 29)
/* Maximum variable size permitted for ARG_CONST_SIZE[_OR_ZERO]. This ensures
* that converting umax_value to int cannot overflow.
*/
-#define BPF_MAX_VAR_SIZ INT_MAX
+#define BPF_MAX_VAR_SIZ (1 << 29)
/* Liveness marks, used for registers and spilled-regs (in stack slots).
* Read marks propagate upwards until they find a write mark; they record that
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index e39b01317b6f..86dfe6b5c243 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1059,6 +1059,11 @@ static int check_ptr_alignment(struct bpf_verifier_env *env,
break;
case PTR_TO_STACK:
pointer_desc = "stack ";
+ /* The stack spill tracking logic in check_stack_write()
+ * and check_stack_read() relies on stack accesses being
+ * aligned.
+ */
+ strict = true;
break;
default:
break;
@@ -1067,6 +1072,29 @@ static int check_ptr_alignment(struct bpf_verifier_env *env,
strict);
}
+/* truncate register to smaller size (in bytes)
+ * must be called with size < BPF_REG_SIZE
+ */
+static void coerce_reg_to_size(struct bpf_reg_state *reg, int size)
+{
+ u64 mask;
+
+ /* clear high bits in bit representation */
+ reg->var_off = tnum_cast(reg->var_off, size);
+
+ /* fix arithmetic bounds */
+ mask = ((u64)1 << (size * 8)) - 1;
+ if ((reg->umin_value & ~mask) == (reg->umax_value & ~mask)) {
+ reg->umin_value &= mask;
+ reg->umax_value &= mask;
+ } else {
+ reg->umin_value = 0;
+ reg->umax_value = mask;
+ }
+ reg->smin_value = reg->umin_value;
+ reg->smax_value = reg->umax_value;
+}
+
/* check whether memory at (regno + off) is accessible for t = (read | write)
* if t==write, value_regno is a register which value is stored into memory
* if t==read, value_regno is a register which will receive the value from memory
@@ -1200,9 +1228,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
if (!err && size < BPF_REG_SIZE && value_regno >= 0 && t == BPF_READ &&
regs[value_regno].type == SCALAR_VALUE) {
/* b/h/w load zero-extends, mark upper bits as known 0 */
- regs[value_regno].var_off =
- tnum_cast(regs[value_regno].var_off, size);
- __update_reg_bounds(&regs[value_regno]);
+ coerce_reg_to_size(&regs[value_regno], size);
}
return err;
}
@@ -1282,6 +1308,7 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno,
tnum_strn(tn_buf, sizeof(tn_buf), regs[regno].var_off);
verbose(env, "invalid variable stack read R%d var_off=%s\n",
regno, tn_buf);
+ return -EACCES;
}
off = regs[regno].off + regs[regno].var_off.value;
if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 ||
@@ -1772,14 +1799,6 @@ static int check_call(struct bpf_verifier_env *env, int func_id, int insn_idx)
return 0;
}
-static void coerce_reg_to_32(struct bpf_reg_state *reg)
-{
- /* clear high 32 bits */
- reg->var_off = tnum_cast(reg->var_off, 4);
- /* Update bounds */
- __update_reg_bounds(reg);
-}
-
static bool signed_add_overflows(s64 a, s64 b)
{
/* Do the add in u64, where overflow is well-defined */
@@ -1800,6 +1819,41 @@ static bool signed_sub_overflows(s64 a, s64 b)
return res > a;
}
+static bool check_reg_sane_offset(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg,
+ enum bpf_reg_type type)
+{
+ bool known = tnum_is_const(reg->var_off);
+ s64 val = reg->var_off.value;
+ s64 smin = reg->smin_value;
+
+ if (known && (val >= BPF_MAX_VAR_OFF || val <= -BPF_MAX_VAR_OFF)) {
+ verbose(env, "math between %s pointer and %lld is not allowed\n",
+ reg_type_str[type], val);
+ return false;
+ }
+
+ if (reg->off >= BPF_MAX_VAR_OFF || reg->off <= -BPF_MAX_VAR_OFF) {
+ verbose(env, "%s pointer offset %d is not allowed\n",
+ reg_type_str[type], reg->off);
+ return false;
+ }
+
+ if (smin == S64_MIN) {
+ verbose(env, "math between %s pointer and register with unbounded min value is not allowed\n",
+ reg_type_str[type]);
+ return false;
+ }
+
+ if (smin >= BPF_MAX_VAR_OFF || smin <= -BPF_MAX_VAR_OFF) {
+ verbose(env, "value %lld makes %s pointer be out of bounds\n",
+ smin, reg_type_str[type]);
+ return false;
+ }
+
+ return true;
+}
+
/* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off.
* Caller should also handle BPF_MOV case separately.
* If we return -EACCES, caller may want to try again treating pointer as a
@@ -1868,6 +1922,10 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
dst_reg->type = ptr_reg->type;
dst_reg->id = ptr_reg->id;
+ if (!check_reg_sane_offset(env, off_reg, ptr_reg->type) ||
+ !check_reg_sane_offset(env, ptr_reg, ptr_reg->type))
+ return -EINVAL;
+
switch (opcode) {
case BPF_ADD:
/* We can take a fixed offset as long as it doesn't overflow
@@ -1998,12 +2056,19 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
return -EACCES;
}
+ if (!check_reg_sane_offset(env, dst_reg, ptr_reg->type))
+ return -EINVAL;
+
__update_reg_bounds(dst_reg);
__reg_deduce_bounds(dst_reg);
__reg_bound_offset(dst_reg);
return 0;
}
+/* WARNING: This function does calculations on 64-bit values, but the actual
+ * execution may occur on 32-bit values. Therefore, things like bitshifts
+ * need extra checks in the 32-bit case.
+ */
static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
struct bpf_insn *insn,
struct bpf_reg_state *dst_reg,
@@ -2014,12 +2079,8 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
bool src_known, dst_known;
s64 smin_val, smax_val;
u64 umin_val, umax_val;
+ u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32;
- if (BPF_CLASS(insn->code) != BPF_ALU64) {
- /* 32-bit ALU ops are (32,32)->64 */
- coerce_reg_to_32(dst_reg);
- coerce_reg_to_32(&src_reg);
- }
smin_val = src_reg.smin_value;
smax_val = src_reg.smax_value;
umin_val = src_reg.umin_value;
@@ -2027,6 +2088,12 @@ 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 &&
+ opcode != BPF_ADD && opcode != BPF_SUB && opcode != BPF_AND) {
+ __mark_reg_unknown(dst_reg);
+ return 0;
+ }
+
switch (opcode) {
case BPF_ADD:
if (signed_add_overflows(dst_reg->smin_value, smin_val) ||
@@ -2155,9 +2222,9 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
__update_reg_bounds(dst_reg);
break;
case BPF_LSH:
- if (umax_val > 63) {
- /* Shifts greater than 63 are undefined. This includes
- * shifts by a negative number.
+ if (umax_val >= insn_bitness) {
+ /* Shifts greater than 31 or 63 are undefined.
+ * This includes shifts by a negative number.
*/
mark_reg_unknown(env, regs, insn->dst_reg);
break;
@@ -2183,27 +2250,29 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
__update_reg_bounds(dst_reg);
break;
case BPF_RSH:
- if (umax_val > 63) {
- /* Shifts greater than 63 are undefined. This includes
- * shifts by a negative number.
+ if (umax_val >= insn_bitness) {
+ /* Shifts greater than 31 or 63 are undefined.
+ * This includes shifts by a negative number.
*/
mark_reg_unknown(env, regs, insn->dst_reg);
break;
}
- /* BPF_RSH is an unsigned shift, so make the appropriate casts */
- if (dst_reg->smin_value < 0) {
- if (umin_val) {
- /* Sign bit will be cleared */
- dst_reg->smin_value = 0;
- } else {
- /* Lost sign bit information */
- dst_reg->smin_value = S64_MIN;
- dst_reg->smax_value = S64_MAX;
- }
- } else {
- dst_reg->smin_value =
- (u64)(dst_reg->smin_value) >> umax_val;
- }
+ /* BPF_RSH is an unsigned shift. If the value in dst_reg might
+ * be negative, then either:
+ * 1) src_reg might be zero, so the sign bit of the result is
+ * unknown, so we lose our signed bounds
+ * 2) it's known negative, thus the unsigned bounds capture the
+ * signed bounds
+ * 3) the signed bounds cross zero, so they tell us nothing
+ * about the result
+ * If the value in dst_reg is known nonnegative, then again the
+ * unsigned bounts capture the signed bounds.
+ * Thus, in all cases it suffices to blow away our signed bounds
+ * and rely on inferring new ones from the unsigned bounds and
+ * var_off of the result.
+ */
+ dst_reg->smin_value = S64_MIN;
+ dst_reg->smax_value = S64_MAX;
if (src_known)
dst_reg->var_off = tnum_rshift(dst_reg->var_off,
umin_val);
@@ -2219,6 +2288,12 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
break;
}
+ if (BPF_CLASS(insn->code) != BPF_ALU64) {
+ /* 32-bit ALU ops are (32,32)->32 */
+ coerce_reg_to_size(dst_reg, 4);
+ coerce_reg_to_size(&src_reg, 4);
+ }
+
__reg_deduce_bounds(dst_reg);
__reg_bound_offset(dst_reg);
return 0;
@@ -2396,17 +2471,20 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
return -EACCES;
}
mark_reg_unknown(env, regs, insn->dst_reg);
- /* high 32 bits are known zero. */
- regs[insn->dst_reg].var_off = tnum_cast(
- regs[insn->dst_reg].var_off, 4);
- __update_reg_bounds(&regs[insn->dst_reg]);
+ coerce_reg_to_size(&regs[insn->dst_reg], 4);
}
} else {
/* case: R = imm
* remember the value we stored into this reg
*/
regs[insn->dst_reg].type = SCALAR_VALUE;
- __mark_reg_known(regs + insn->dst_reg, insn->imm);
+ if (BPF_CLASS(insn->code) == BPF_ALU64) {
+ __mark_reg_known(regs + insn->dst_reg,
+ insn->imm);
+ } else {
+ __mark_reg_known(regs + insn->dst_reg,
+ (u32)insn->imm);
+ }
}
} else if (opcode > BPF_END) {
@@ -3437,15 +3515,14 @@ static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur,
return range_within(rold, rcur) &&
tnum_in(rold->var_off, rcur->var_off);
} else {
- /* if we knew anything about the old value, we're not
- * equal, because we can't know anything about the
- * scalar value of the pointer in the new value.
+ /* We're trying to use a pointer in place of a scalar.
+ * Even if the scalar was unbounded, this could lead to
+ * pointer leaks because scalars are allowed to leak
+ * while pointers are not. We could make this safe in
+ * special cases if root is calling us, but it's
+ * probably not worth the hassle.
*/
- return rold->umin_value == 0 &&
- rold->umax_value == U64_MAX &&
- rold->smin_value == S64_MIN &&
- rold->smax_value == S64_MAX &&
- tnum_is_unknown(rold->var_off);
+ return false;
}
case PTR_TO_MAP_VALUE:
/* If the new min/max/var_off satisfy the old ones and
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index b03ecfd7185b..961c1426fbf2 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -606,7 +606,6 @@ static struct bpf_test tests[] = {
},
.errstr = "misaligned stack access",
.result = REJECT,
- .flags = F_LOAD_WITH_STRICT_ALIGNMENT,
},
{
"invalid map_fd for function call",
@@ -1797,7 +1796,6 @@ static struct bpf_test tests[] = {
},
.result = REJECT,
.errstr = "misaligned stack access off (0x0; 0x0)+-8+2 size 8",
- .flags = F_LOAD_WITH_STRICT_ALIGNMENT,
},
{
"PTR_TO_STACK store/load - bad alignment on reg",
@@ -1810,7 +1808,6 @@ static struct bpf_test tests[] = {
},
.result = REJECT,
.errstr = "misaligned stack access off (0x0; 0x0)+-10+8 size 8",
- .flags = F_LOAD_WITH_STRICT_ALIGNMENT,
},
{
"PTR_TO_STACK store/load - out of bounds low",
@@ -6324,7 +6321,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map1 = { 3 },
- .errstr = "R0 min value is negative",
+ .errstr = "unbounded min value",
.result = REJECT,
},
{
@@ -6348,7 +6345,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map1 = { 3 },
- .errstr = "R0 min value is negative",
+ .errstr = "unbounded min value",
.result = REJECT,
},
{
@@ -6374,7 +6371,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map1 = { 3 },
- .errstr = "R8 invalid mem access 'inv'",
+ .errstr = "unbounded min value",
.result = REJECT,
},
{
@@ -6399,7 +6396,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map1 = { 3 },
- .errstr = "R8 invalid mem access 'inv'",
+ .errstr = "unbounded min value",
.result = REJECT,
},
{
@@ -6447,7 +6444,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map1 = { 3 },
- .errstr = "R0 min value is negative",
+ .errstr = "unbounded min value",
.result = REJECT,
},
{
@@ -6518,7 +6515,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map1 = { 3 },
- .errstr = "R0 min value is negative",
+ .errstr = "unbounded min value",
.result = REJECT,
},
{
@@ -6569,7 +6566,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map1 = { 3 },
- .errstr = "R0 min value is negative",
+ .errstr = "unbounded min value",
.result = REJECT,
},
{
@@ -6596,7 +6593,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map1 = { 3 },
- .errstr = "R0 min value is negative",
+ .errstr = "unbounded min value",
.result = REJECT,
},
{
@@ -6622,7 +6619,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map1 = { 3 },
- .errstr = "R0 min value is negative",
+ .errstr = "unbounded min value",
.result = REJECT,
},
{
@@ -6651,7 +6648,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map1 = { 3 },
- .errstr = "R0 min value is negative",
+ .errstr = "unbounded min value",
.result = REJECT,
},
{
@@ -6681,7 +6678,7 @@ static struct bpf_test tests[] = {
BPF_JMP_IMM(BPF_JA, 0, 0, -7),
},
.fixup_map1 = { 4 },
- .errstr = "R0 min value is negative",
+ .errstr = "unbounded min value",
.result = REJECT,
},
{
@@ -6709,8 +6706,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map1 = { 3 },
- .errstr_unpriv = "R0 pointer comparison prohibited",
- .errstr = "R0 min value is negative",
+ .errstr = "unbounded min value",
.result = REJECT,
.result_unpriv = REJECT,
},
@@ -6766,6 +6762,462 @@ static struct bpf_test tests[] = {
.result = REJECT,
},
{
+ "bounds check based on zero-extended MOV",
+ .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, 4),
+ /* r2 = 0x0000'0000'ffff'ffff */
+ BPF_MOV32_IMM(BPF_REG_2, 0xffffffff),
+ /* r2 = 0 */
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_2, 32),
+ /* no-op */
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_2),
+ /* access at offset 0 */
+ BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0),
+ /* exit */
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .result = ACCEPT
+ },
+ {
+ "bounds check based on sign-extended MOV. test1",
+ .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, 4),
+ /* r2 = 0xffff'ffff'ffff'ffff */
+ BPF_MOV64_IMM(BPF_REG_2, 0xffffffff),
+ /* r2 = 0xffff'ffff */
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_2, 32),
+ /* r0 = <oob pointer> */
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_2),
+ /* access to OOB pointer */
+ BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0),
+ /* exit */
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .errstr = "map_value pointer and 4294967295",
+ .result = REJECT
+ },
+ {
+ "bounds check based on sign-extended MOV. test2",
+ .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, 4),
+ /* r2 = 0xffff'ffff'ffff'ffff */
+ BPF_MOV64_IMM(BPF_REG_2, 0xffffffff),
+ /* r2 = 0xfff'ffff */
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_2, 36),
+ /* r0 = <oob pointer> */
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_2),
+ /* access to OOB pointer */
+ BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0),
+ /* exit */
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .errstr = "R0 min value is outside of the array range",
+ .result = REJECT
+ },
+ {
+ "bounds check based on reg_off + var_off + insn_off. test1",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
+ offsetof(struct __sk_buff, mark)),
+ 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, 4),
+ BPF_ALU64_IMM(BPF_AND, BPF_REG_6, 1),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, (1 << 29) - 1),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_6),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, (1 << 29) - 1),
+ BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 3),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 4 },
+ .errstr = "value_size=8 off=1073741825",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ },
+ {
+ "bounds check based on reg_off + var_off + insn_off. test2",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
+ offsetof(struct __sk_buff, mark)),
+ 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, 4),
+ BPF_ALU64_IMM(BPF_AND, BPF_REG_6, 1),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, (1 << 30) - 1),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_6),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, (1 << 29) - 1),
+ BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 3),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 4 },
+ .errstr = "value 1073741823",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ },
+ {
+ "bounds check after truncation of non-boundary-crossing range",
+ .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, 9),
+ /* r1 = [0x00, 0xff] */
+ BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+ BPF_MOV64_IMM(BPF_REG_2, 1),
+ /* r2 = 0x10'0000'0000 */
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_2, 36),
+ /* r1 = [0x10'0000'0000, 0x10'0000'00ff] */
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_2),
+ /* r1 = [0x10'7fff'ffff, 0x10'8000'00fe] */
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 0x7fffffff),
+ /* r1 = [0x00, 0xff] */
+ BPF_ALU32_IMM(BPF_SUB, BPF_REG_1, 0x7fffffff),
+ /* r1 = 0 */
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_1, 8),
+ /* no-op */
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
+ /* access at offset 0 */
+ BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0),
+ /* exit */
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .result = ACCEPT
+ },
+ {
+ "bounds check after truncation of boundary-crossing range (1)",
+ .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, 9),
+ /* r1 = [0x00, 0xff] */
+ BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 0xffffff80 >> 1),
+ /* r1 = [0xffff'ff80, 0x1'0000'007f] */
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 0xffffff80 >> 1),
+ /* r1 = [0xffff'ff80, 0xffff'ffff] or
+ * [0x0000'0000, 0x0000'007f]
+ */
+ BPF_ALU32_IMM(BPF_ADD, BPF_REG_1, 0),
+ BPF_ALU64_IMM(BPF_SUB, BPF_REG_1, 0xffffff80 >> 1),
+ /* r1 = [0x00, 0xff] or
+ * [0xffff'ffff'0000'0080, 0xffff'ffff'ffff'ffff]
+ */
+ BPF_ALU64_IMM(BPF_SUB, BPF_REG_1, 0xffffff80 >> 1),
+ /* r1 = 0 or
+ * [0x00ff'ffff'ff00'0000, 0x00ff'ffff'ffff'ffff]
+ */
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_1, 8),
+ /* no-op or OOB pointer computation */
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
+ /* potentially OOB access */
+ BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0),
+ /* exit */
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ /* not actually fully unbounded, but the bound is very high */
+ .errstr = "R0 unbounded memory access",
+ .result = REJECT
+ },
+ {
+ "bounds check after truncation of boundary-crossing range (2)",
+ .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, 9),
+ /* r1 = [0x00, 0xff] */
+ BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 0xffffff80 >> 1),
+ /* r1 = [0xffff'ff80, 0x1'0000'007f] */
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 0xffffff80 >> 1),
+ /* r1 = [0xffff'ff80, 0xffff'ffff] or
+ * [0x0000'0000, 0x0000'007f]
+ * difference to previous test: truncation via MOV32
+ * instead of ALU32.
+ */
+ BPF_MOV32_REG(BPF_REG_1, BPF_REG_1),
+ BPF_ALU64_IMM(BPF_SUB, BPF_REG_1, 0xffffff80 >> 1),
+ /* r1 = [0x00, 0xff] or
+ * [0xffff'ffff'0000'0080, 0xffff'ffff'ffff'ffff]
+ */
+ BPF_ALU64_IMM(BPF_SUB, BPF_REG_1, 0xffffff80 >> 1),
+ /* r1 = 0 or
+ * [0x00ff'ffff'ff00'0000, 0x00ff'ffff'ffff'ffff]
+ */
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_1, 8),
+ /* no-op or OOB pointer computation */
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
+ /* potentially OOB access */
+ BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0),
+ /* exit */
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ /* not actually fully unbounded, but the bound is very high */
+ .errstr = "R0 unbounded memory access",
+ .result = REJECT
+ },
+ {
+ "bounds check after wrapping 32-bit addition",
+ .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, 5),
+ /* r1 = 0x7fff'ffff */
+ BPF_MOV64_IMM(BPF_REG_1, 0x7fffffff),
+ /* r1 = 0xffff'fffe */
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 0x7fffffff),
+ /* r1 = 0 */
+ BPF_ALU32_IMM(BPF_ADD, BPF_REG_1, 2),
+ /* no-op */
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
+ /* access at offset 0 */
+ BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0),
+ /* exit */
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .result = ACCEPT
+ },
+ {
+ "bounds check after shift with oversized count operand",
+ .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, 6),
+ BPF_MOV64_IMM(BPF_REG_2, 32),
+ BPF_MOV64_IMM(BPF_REG_1, 1),
+ /* r1 = (u32)1 << (u32)32 = ? */
+ BPF_ALU32_REG(BPF_LSH, BPF_REG_1, BPF_REG_2),
+ /* r1 = [0x0000, 0xffff] */
+ BPF_ALU64_IMM(BPF_AND, BPF_REG_1, 0xffff),
+ /* computes unknown pointer, potentially OOB */
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
+ /* potentially OOB access */
+ BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0),
+ /* exit */
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .errstr = "R0 max value is outside of the array range",
+ .result = REJECT
+ },
+ {
+ "bounds check after right shift of maybe-negative number",
+ .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, 6),
+ /* r1 = [0x00, 0xff] */
+ BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+ /* r1 = [-0x01, 0xfe] */
+ BPF_ALU64_IMM(BPF_SUB, BPF_REG_1, 1),
+ /* r1 = 0 or 0xff'ffff'ffff'ffff */
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_1, 8),
+ /* r1 = 0 or 0xffff'ffff'ffff */
+ BPF_ALU64_IMM(BPF_RSH, BPF_REG_1, 8),
+ /* computes unknown pointer, potentially OOB */
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
+ /* potentially OOB access */
+ BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, 0),
+ /* exit */
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .errstr = "R0 unbounded memory access",
+ .result = REJECT
+ },
+ {
+ "bounds check map access with off+size signed 32bit overflow. test1",
+ .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_JNE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 0x7ffffffe),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0),
+ BPF_JMP_A(0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .errstr = "map_value pointer and 2147483646",
+ .result = REJECT
+ },
+ {
+ "bounds check map access with off+size signed 32bit overflow. test2",
+ .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_JNE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 0x1fffffff),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 0x1fffffff),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 0x1fffffff),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0),
+ BPF_JMP_A(0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .errstr = "pointer offset 1073741822",
+ .result = REJECT
+ },
+ {
+ "bounds check map access with off+size signed 32bit overflow. test3",
+ .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_JNE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_ALU64_IMM(BPF_SUB, BPF_REG_0, 0x1fffffff),
+ BPF_ALU64_IMM(BPF_SUB, BPF_REG_0, 0x1fffffff),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 2),
+ BPF_JMP_A(0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .errstr = "pointer offset -1073741822",
+ .result = REJECT
+ },
+ {
+ "bounds check map access with off+size signed 32bit overflow. test4",
+ .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_JNE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_IMM(BPF_REG_1, 1000000),
+ BPF_ALU64_IMM(BPF_MUL, BPF_REG_1, 1000000),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 2),
+ BPF_JMP_A(0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .errstr = "map_value pointer and 1000000000000",
+ .result = REJECT
+ },
+ {
+ "pointer/scalar confusion in state equality check (way 1)",
+ .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, 2),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0),
+ BPF_JMP_A(1),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_10),
+ BPF_JMP_A(0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .result = ACCEPT,
+ .result_unpriv = REJECT,
+ .errstr_unpriv = "R0 leaks addr as return value"
+ },
+ {
+ "pointer/scalar confusion in state equality check (way 2)",
+ .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_JNE, BPF_REG_0, 0, 2),
+ BPF_MOV64_REG(BPF_REG_0, BPF_REG_10),
+ BPF_JMP_A(1),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map1 = { 3 },
+ .result = ACCEPT,
+ .result_unpriv = REJECT,
+ .errstr_unpriv = "R0 leaks addr as return value"
+ },
+ {
"variable-offset ctx access",
.insns = {
/* Get an unknown value */
@@ -6807,6 +7259,71 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_LWT_IN,
},
{
+ "indirect variable-offset stack access",
+ .insns = {
+ /* Fill the top 8 bytes of the stack */
+ BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+ /* Get an unknown value */
+ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
+ /* Make it small and 4-byte aligned */
+ BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
+ BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 8),
+ /* add it to fp. We now have either fp-4 or fp-8, but
+ * we don't know which
+ */
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
+ /* dereference it indirectly */
+ 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_map1 = { 5 },
+ .errstr = "variable stack read R2",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_LWT_IN,
+ },
+ {
+ "direct stack access with 32-bit wraparound. test1",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 0x7fffffff),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 0x7fffffff),
+ BPF_MOV32_IMM(BPF_REG_0, 0),
+ BPF_STX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+ BPF_EXIT_INSN()
+ },
+ .errstr = "fp pointer and 2147483647",
+ .result = REJECT
+ },
+ {
+ "direct stack access with 32-bit wraparound. test2",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 0x3fffffff),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 0x3fffffff),
+ BPF_MOV32_IMM(BPF_REG_0, 0),
+ BPF_STX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+ BPF_EXIT_INSN()
+ },
+ .errstr = "fp pointer and 1073741823",
+ .result = REJECT
+ },
+ {
+ "direct stack access with 32-bit wraparound. test3",
+ .insns = {
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 0x1fffffff),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 0x1fffffff),
+ BPF_MOV32_IMM(BPF_REG_0, 0),
+ BPF_STX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+ BPF_EXIT_INSN()
+ },
+ .errstr = "fp pointer offset 1073741822",
+ .result = REJECT
+ },
+ {
"liveness pruning and write screening",
.insns = {
/* Get an unknown value */