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Diffstat (limited to 'kernel/bpf/verifier.c')
-rw-r--r--kernel/bpf/verifier.c203
1 files changed, 171 insertions, 32 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index eae6cb1fe653..8c1c21cd50b4 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1095,7 +1095,7 @@ static int check_subprogs(struct bpf_verifier_env *env)
for (i = 0; i < insn_cnt; i++) {
u8 code = insn[i].code;
- if (BPF_CLASS(code) != BPF_JMP)
+ if (BPF_CLASS(code) != BPF_JMP && BPF_CLASS(code) != BPF_JMP32)
goto next;
if (BPF_OP(code) == BPF_EXIT || BPF_OP(code) == BPF_CALL)
goto next;
@@ -4031,14 +4031,49 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *vstate,
* 0 - branch will not be taken and fall-through to next insn
* -1 - unknown. Example: "if (reg < 5)" is unknown when register value range [0,10]
*/
-static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode)
+static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode,
+ bool is_jmp32)
{
+ struct bpf_reg_state reg_lo;
s64 sval;
if (__is_pointer_value(false, reg))
return -1;
- sval = (s64)val;
+ if (is_jmp32) {
+ reg_lo = *reg;
+ reg = &reg_lo;
+ /* For JMP32, only low 32 bits are compared, coerce_reg_to_size
+ * could truncate high bits and update umin/umax according to
+ * information of low bits.
+ */
+ coerce_reg_to_size(reg, 4);
+ /* smin/smax need special handling. For example, after coerce,
+ * if smin_value is 0x00000000ffffffffLL, the value is -1 when
+ * used as operand to JMP32. It is a negative number from s32's
+ * point of view, while it is a positive number when seen as
+ * s64. The smin/smax are kept as s64, therefore, when used with
+ * JMP32, they need to be transformed into s32, then sign
+ * extended back to s64.
+ *
+ * Also, smin/smax were copied from umin/umax. If umin/umax has
+ * different sign bit, then min/max relationship doesn't
+ * maintain after casting into s32, for this case, set smin/smax
+ * to safest range.
+ */
+ if ((reg->umax_value ^ reg->umin_value) &
+ (1ULL << 31)) {
+ reg->smin_value = S32_MIN;
+ reg->smax_value = S32_MAX;
+ }
+ reg->smin_value = (s64)(s32)reg->smin_value;
+ reg->smax_value = (s64)(s32)reg->smax_value;
+
+ val = (u32)val;
+ sval = (s64)(s32)val;
+ } else {
+ sval = (s64)val;
+ }
switch (opcode) {
case BPF_JEQ:
@@ -4108,6 +4143,29 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode)
return -1;
}
+/* Generate min value of the high 32-bit from TNUM info. */
+static u64 gen_hi_min(struct tnum var)
+{
+ return var.value & ~0xffffffffULL;
+}
+
+/* Generate max value of the high 32-bit from TNUM info. */
+static u64 gen_hi_max(struct tnum var)
+{
+ return (var.value | var.mask) & ~0xffffffffULL;
+}
+
+/* Return true if VAL is compared with a s64 sign extended from s32, and they
+ * are with the same signedness.
+ */
+static bool cmp_val_with_extended_s64(s64 sval, struct bpf_reg_state *reg)
+{
+ return ((s32)sval >= 0 &&
+ reg->smin_value >= 0 && reg->smax_value <= S32_MAX) ||
+ ((s32)sval < 0 &&
+ reg->smax_value <= 0 && reg->smin_value >= S32_MIN);
+}
+
/* Adjusts the register min/max values in the case that the dst_reg is the
* variable register that we are working on, and src_reg is a constant or we're
* simply doing a BPF_K check.
@@ -4115,7 +4173,7 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode)
*/
static void reg_set_min_max(struct bpf_reg_state *true_reg,
struct bpf_reg_state *false_reg, u64 val,
- u8 opcode)
+ u8 opcode, bool is_jmp32)
{
s64 sval;
@@ -4128,7 +4186,8 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
if (__is_pointer_value(false, false_reg))
return;
- sval = (s64)val;
+ val = is_jmp32 ? (u32)val : val;
+ sval = is_jmp32 ? (s64)(s32)val : (s64)val;
switch (opcode) {
case BPF_JEQ:
@@ -4141,7 +4200,15 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
* if it is true we know the value for sure. Likewise for
* BPF_JNE.
*/
- __mark_reg_known(reg, val);
+ if (is_jmp32) {
+ u64 old_v = reg->var_off.value;
+ u64 hi_mask = ~0xffffffffULL;
+
+ reg->var_off.value = (old_v & hi_mask) | val;
+ reg->var_off.mask &= hi_mask;
+ } else {
+ __mark_reg_known(reg, val);
+ }
break;
}
case BPF_JSET:
@@ -4157,6 +4224,10 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
u64 false_umax = opcode == BPF_JGT ? val : val - 1;
u64 true_umin = opcode == BPF_JGT ? val + 1 : val;
+ if (is_jmp32) {
+ false_umax += gen_hi_max(false_reg->var_off);
+ true_umin += gen_hi_min(true_reg->var_off);
+ }
false_reg->umax_value = min(false_reg->umax_value, false_umax);
true_reg->umin_value = max(true_reg->umin_value, true_umin);
break;
@@ -4167,6 +4238,11 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
s64 false_smax = opcode == BPF_JSGT ? sval : sval - 1;
s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval;
+ /* If the full s64 was not sign-extended from s32 then don't
+ * deduct further info.
+ */
+ if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg))
+ break;
false_reg->smax_value = min(false_reg->smax_value, false_smax);
true_reg->smin_value = max(true_reg->smin_value, true_smin);
break;
@@ -4177,6 +4253,10 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
u64 false_umin = opcode == BPF_JLT ? val : val + 1;
u64 true_umax = opcode == BPF_JLT ? val - 1 : val;
+ if (is_jmp32) {
+ false_umin += gen_hi_min(false_reg->var_off);
+ true_umax += gen_hi_max(true_reg->var_off);
+ }
false_reg->umin_value = max(false_reg->umin_value, false_umin);
true_reg->umax_value = min(true_reg->umax_value, true_umax);
break;
@@ -4187,6 +4267,8 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
s64 false_smin = opcode == BPF_JSLT ? sval : sval + 1;
s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval;
+ if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg))
+ break;
false_reg->smin_value = max(false_reg->smin_value, false_smin);
true_reg->smax_value = min(true_reg->smax_value, true_smax);
break;
@@ -4213,14 +4295,15 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
*/
static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
struct bpf_reg_state *false_reg, u64 val,
- u8 opcode)
+ u8 opcode, bool is_jmp32)
{
s64 sval;
if (__is_pointer_value(false, false_reg))
return;
- sval = (s64)val;
+ val = is_jmp32 ? (u32)val : val;
+ sval = is_jmp32 ? (s64)(s32)val : (s64)val;
switch (opcode) {
case BPF_JEQ:
@@ -4229,7 +4312,15 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
struct bpf_reg_state *reg =
opcode == BPF_JEQ ? true_reg : false_reg;
- __mark_reg_known(reg, val);
+ if (is_jmp32) {
+ u64 old_v = reg->var_off.value;
+ u64 hi_mask = ~0xffffffffULL;
+
+ reg->var_off.value = (old_v & hi_mask) | val;
+ reg->var_off.mask &= hi_mask;
+ } else {
+ __mark_reg_known(reg, val);
+ }
break;
}
case BPF_JSET:
@@ -4245,6 +4336,10 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
u64 false_umin = opcode == BPF_JGT ? val : val + 1;
u64 true_umax = opcode == BPF_JGT ? val - 1 : val;
+ if (is_jmp32) {
+ false_umin += gen_hi_min(false_reg->var_off);
+ true_umax += gen_hi_max(true_reg->var_off);
+ }
false_reg->umin_value = max(false_reg->umin_value, false_umin);
true_reg->umax_value = min(true_reg->umax_value, true_umax);
break;
@@ -4255,6 +4350,8 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
s64 false_smin = opcode == BPF_JSGT ? sval : sval + 1;
s64 true_smax = opcode == BPF_JSGT ? sval - 1 : sval;
+ if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg))
+ break;
false_reg->smin_value = max(false_reg->smin_value, false_smin);
true_reg->smax_value = min(true_reg->smax_value, true_smax);
break;
@@ -4265,6 +4362,10 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
u64 false_umax = opcode == BPF_JLT ? val : val - 1;
u64 true_umin = opcode == BPF_JLT ? val + 1 : val;
+ if (is_jmp32) {
+ false_umax += gen_hi_max(false_reg->var_off);
+ true_umin += gen_hi_min(true_reg->var_off);
+ }
false_reg->umax_value = min(false_reg->umax_value, false_umax);
true_reg->umin_value = max(true_reg->umin_value, true_umin);
break;
@@ -4275,6 +4376,8 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
s64 false_smax = opcode == BPF_JSLT ? sval : sval - 1;
s64 true_smin = opcode == BPF_JSLT ? sval + 1 : sval;
+ if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg))
+ break;
false_reg->smax_value = min(false_reg->smax_value, false_smax);
true_reg->smin_value = max(true_reg->smin_value, true_smin);
break;
@@ -4416,6 +4519,10 @@ static bool try_match_pkt_pointers(const struct bpf_insn *insn,
if (BPF_SRC(insn->code) != BPF_X)
return false;
+ /* Pointers are always 64-bit. */
+ if (BPF_CLASS(insn->code) == BPF_JMP32)
+ return false;
+
switch (BPF_OP(insn->code)) {
case BPF_JGT:
if ((dst_reg->type == PTR_TO_PACKET &&
@@ -4508,16 +4615,18 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs;
struct bpf_reg_state *dst_reg, *other_branch_regs;
u8 opcode = BPF_OP(insn->code);
+ bool is_jmp32;
int err;
- if (opcode > BPF_JSLE) {
- verbose(env, "invalid BPF_JMP opcode %x\n", opcode);
+ /* Only conditional jumps are expected to reach here. */
+ if (opcode == BPF_JA || opcode > BPF_JSLE) {
+ verbose(env, "invalid BPF_JMP/JMP32 opcode %x\n", opcode);
return -EINVAL;
}
if (BPF_SRC(insn->code) == BPF_X) {
if (insn->imm != 0) {
- verbose(env, "BPF_JMP uses reserved fields\n");
+ verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
return -EINVAL;
}
@@ -4533,7 +4642,7 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
}
} else {
if (insn->src_reg != BPF_REG_0) {
- verbose(env, "BPF_JMP uses reserved fields\n");
+ verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
return -EINVAL;
}
}
@@ -4544,9 +4653,11 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
return err;
dst_reg = &regs[insn->dst_reg];
+ is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;
if (BPF_SRC(insn->code) == BPF_K) {
- int pred = is_branch_taken(dst_reg, insn->imm, opcode);
+ int pred = is_branch_taken(dst_reg, insn->imm, opcode,
+ is_jmp32);
if (pred == 1) {
/* only follow the goto, ignore fall-through */
@@ -4574,30 +4685,51 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
* comparable.
*/
if (BPF_SRC(insn->code) == BPF_X) {
+ struct bpf_reg_state *src_reg = &regs[insn->src_reg];
+ struct bpf_reg_state lo_reg0 = *dst_reg;
+ struct bpf_reg_state lo_reg1 = *src_reg;
+ struct bpf_reg_state *src_lo, *dst_lo;
+
+ dst_lo = &lo_reg0;
+ src_lo = &lo_reg1;
+ coerce_reg_to_size(dst_lo, 4);
+ coerce_reg_to_size(src_lo, 4);
+
if (dst_reg->type == SCALAR_VALUE &&
- regs[insn->src_reg].type == SCALAR_VALUE) {
- if (tnum_is_const(regs[insn->src_reg].var_off))
+ src_reg->type == SCALAR_VALUE) {
+ if (tnum_is_const(src_reg->var_off) ||
+ (is_jmp32 && tnum_is_const(src_lo->var_off)))
reg_set_min_max(&other_branch_regs[insn->dst_reg],
- dst_reg, regs[insn->src_reg].var_off.value,
- opcode);
- else if (tnum_is_const(dst_reg->var_off))
+ dst_reg,
+ is_jmp32
+ ? src_lo->var_off.value
+ : src_reg->var_off.value,
+ opcode, is_jmp32);
+ else if (tnum_is_const(dst_reg->var_off) ||
+ (is_jmp32 && tnum_is_const(dst_lo->var_off)))
reg_set_min_max_inv(&other_branch_regs[insn->src_reg],
- &regs[insn->src_reg],
- dst_reg->var_off.value, opcode);
- else if (opcode == BPF_JEQ || opcode == BPF_JNE)
+ src_reg,
+ is_jmp32
+ ? dst_lo->var_off.value
+ : dst_reg->var_off.value,
+ opcode, is_jmp32);
+ else if (!is_jmp32 &&
+ (opcode == BPF_JEQ || opcode == BPF_JNE))
/* Comparing for equality, we can combine knowledge */
reg_combine_min_max(&other_branch_regs[insn->src_reg],
&other_branch_regs[insn->dst_reg],
- &regs[insn->src_reg],
- &regs[insn->dst_reg], opcode);
+ src_reg, dst_reg, opcode);
}
} else if (dst_reg->type == SCALAR_VALUE) {
reg_set_min_max(&other_branch_regs[insn->dst_reg],
- dst_reg, insn->imm, opcode);
+ dst_reg, insn->imm, opcode, is_jmp32);
}
- /* detect if R == 0 where R is returned from bpf_map_lookup_elem() */
- if (BPF_SRC(insn->code) == BPF_K &&
+ /* detect if R == 0 where R is returned from bpf_map_lookup_elem().
+ * NOTE: these optimizations below are related with pointer comparison
+ * which will never be JMP32.
+ */
+ if (!is_jmp32 && BPF_SRC(insn->code) == BPF_K &&
insn->imm == 0 && (opcode == BPF_JEQ || opcode == BPF_JNE) &&
reg_type_may_be_null(dst_reg->type)) {
/* Mark all identical registers in each branch as either
@@ -4926,7 +5058,8 @@ peek_stack:
goto check_state;
t = insn_stack[cur_stack - 1];
- if (BPF_CLASS(insns[t].code) == BPF_JMP) {
+ if (BPF_CLASS(insns[t].code) == BPF_JMP ||
+ BPF_CLASS(insns[t].code) == BPF_JMP32) {
u8 opcode = BPF_OP(insns[t].code);
if (opcode == BPF_EXIT) {
@@ -6082,7 +6215,7 @@ static int do_check(struct bpf_verifier_env *env)
if (err)
return err;
- } else if (class == BPF_JMP) {
+ } else if (class == BPF_JMP || class == BPF_JMP32) {
u8 opcode = BPF_OP(insn->code);
if (opcode == BPF_CALL) {
@@ -6090,7 +6223,8 @@ static int do_check(struct bpf_verifier_env *env)
insn->off != 0 ||
(insn->src_reg != BPF_REG_0 &&
insn->src_reg != BPF_PSEUDO_CALL) ||
- insn->dst_reg != BPF_REG_0) {
+ insn->dst_reg != BPF_REG_0 ||
+ class == BPF_JMP32) {
verbose(env, "BPF_CALL uses reserved fields\n");
return -EINVAL;
}
@@ -6106,7 +6240,8 @@ static int do_check(struct bpf_verifier_env *env)
if (BPF_SRC(insn->code) != BPF_K ||
insn->imm != 0 ||
insn->src_reg != BPF_REG_0 ||
- insn->dst_reg != BPF_REG_0) {
+ insn->dst_reg != BPF_REG_0 ||
+ class == BPF_JMP32) {
verbose(env, "BPF_JA uses reserved fields\n");
return -EINVAL;
}
@@ -6118,7 +6253,8 @@ static int do_check(struct bpf_verifier_env *env)
if (BPF_SRC(insn->code) != BPF_K ||
insn->imm != 0 ||
insn->src_reg != BPF_REG_0 ||
- insn->dst_reg != BPF_REG_0) {
+ insn->dst_reg != BPF_REG_0 ||
+ class == BPF_JMP32) {
verbose(env, "BPF_EXIT uses reserved fields\n");
return -EINVAL;
}
@@ -6635,6 +6771,9 @@ static bool insn_is_cond_jump(u8 code)
{
u8 op;
+ if (BPF_CLASS(code) == BPF_JMP32)
+ return true;
+
if (BPF_CLASS(code) != BPF_JMP)
return false;
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-09 02:28:55 +0000