aboutsummaryrefslogtreecommitdiffstats
path: root/net/core/filter.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/core/filter.c')
-rw-r--r--net/core/filter.c196
1 files changed, 72 insertions, 124 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index 328aaf6ff4d1..842f8393121d 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -672,14 +672,10 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
/* A = *(u16 *) (ctx + offsetof(protocol)) */
- *insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
- offsetof(struct sk_buff, protocol));
- insn++;
-
+ *insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
+ offsetof(struct sk_buff, protocol));
/* A = ntohs(A) [emitting a nop or swap16] */
- insn->code = BPF_ALU | BPF_END | BPF_FROM_BE;
- insn->a_reg = BPF_REG_A;
- insn->imm = 16;
+ *insn = BPF_ENDIAN(BPF_FROM_BE, BPF_REG_A, 16);
break;
case SKF_AD_OFF + SKF_AD_PKTTYPE:
@@ -688,37 +684,27 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
if (insn->off < 0)
return false;
insn++;
-
*insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, PKT_TYPE_MAX);
break;
case SKF_AD_OFF + SKF_AD_IFINDEX:
case SKF_AD_OFF + SKF_AD_HATYPE:
- *insn = BPF_LDX_MEM(size_to_bpf(FIELD_SIZEOF(struct sk_buff, dev)),
- BPF_REG_TMP, BPF_REG_CTX,
- offsetof(struct sk_buff, dev));
- insn++;
-
- /* if (tmp != 0) goto pc+1 */
- *insn = BPF_JMP_IMM(BPF_JNE, BPF_REG_TMP, 0, 1);
- insn++;
-
- *insn = BPF_EXIT_INSN();
- insn++;
-
BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
-
- insn->a_reg = BPF_REG_A;
- insn->x_reg = BPF_REG_TMP;
-
- if (fp->k == SKF_AD_OFF + SKF_AD_IFINDEX) {
- insn->code = BPF_LDX | BPF_MEM | BPF_W;
- insn->off = offsetof(struct net_device, ifindex);
- } else {
- insn->code = BPF_LDX | BPF_MEM | BPF_H;
- insn->off = offsetof(struct net_device, type);
- }
+ BUILD_BUG_ON(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)) < 0);
+
+ *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)),
+ BPF_REG_TMP, BPF_REG_CTX,
+ offsetof(struct sk_buff, dev));
+ /* if (tmp != 0) goto pc + 1 */
+ *insn++ = BPF_JMP_IMM(BPF_JNE, BPF_REG_TMP, 0, 1);
+ *insn++ = BPF_EXIT_INSN();
+ if (fp->k == SKF_AD_OFF + SKF_AD_IFINDEX)
+ *insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_TMP,
+ offsetof(struct net_device, ifindex));
+ else
+ *insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_TMP,
+ offsetof(struct net_device, type));
break;
case SKF_AD_OFF + SKF_AD_MARK:
@@ -745,22 +731,17 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
case SKF_AD_OFF + SKF_AD_VLAN_TAG:
case SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
-
- /* A = *(u16 *) (ctx + offsetof(vlan_tci)) */
- *insn = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
- offsetof(struct sk_buff, vlan_tci));
- insn++;
-
BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
+ /* A = *(u16 *) (ctx + offsetof(vlan_tci)) */
+ *insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
+ offsetof(struct sk_buff, vlan_tci));
if (fp->k == SKF_AD_OFF + SKF_AD_VLAN_TAG) {
*insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A,
~VLAN_TAG_PRESENT);
} else {
/* A >>= 12 */
- *insn = BPF_ALU32_IMM(BPF_RSH, BPF_REG_A, 12);
- insn++;
-
+ *insn++ = BPF_ALU32_IMM(BPF_RSH, BPF_REG_A, 12);
/* A &= 1 */
*insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, 1);
}
@@ -772,34 +753,27 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
case SKF_AD_OFF + SKF_AD_CPU:
case SKF_AD_OFF + SKF_AD_RANDOM:
/* arg1 = ctx */
- *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_ARG1, BPF_REG_CTX);
- insn++;
-
+ *insn++ = BPF_MOV64_REG(BPF_REG_ARG1, BPF_REG_CTX);
/* arg2 = A */
- *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_ARG2, BPF_REG_A);
- insn++;
-
+ *insn++ = BPF_MOV64_REG(BPF_REG_ARG2, BPF_REG_A);
/* arg3 = X */
- *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_ARG3, BPF_REG_X);
- insn++;
-
+ *insn++ = BPF_MOV64_REG(BPF_REG_ARG3, BPF_REG_X);
/* Emit call(ctx, arg2=A, arg3=X) */
- insn->code = BPF_JMP | BPF_CALL;
switch (fp->k) {
case SKF_AD_OFF + SKF_AD_PAY_OFFSET:
- insn->imm = __skb_get_pay_offset - __bpf_call_base;
+ *insn = BPF_EMIT_CALL(__skb_get_pay_offset);
break;
case SKF_AD_OFF + SKF_AD_NLATTR:
- insn->imm = __skb_get_nlattr - __bpf_call_base;
+ *insn = BPF_EMIT_CALL(__skb_get_nlattr);
break;
case SKF_AD_OFF + SKF_AD_NLATTR_NEST:
- insn->imm = __skb_get_nlattr_nest - __bpf_call_base;
+ *insn = BPF_EMIT_CALL(__skb_get_nlattr_nest);
break;
case SKF_AD_OFF + SKF_AD_CPU:
- insn->imm = __get_raw_cpu_id - __bpf_call_base;
+ *insn = BPF_EMIT_CALL(__get_raw_cpu_id);
break;
case SKF_AD_OFF + SKF_AD_RANDOM:
- insn->imm = __get_random_u32 - __bpf_call_base;
+ *insn = BPF_EMIT_CALL(__get_random_u32);
break;
}
break;
@@ -871,9 +845,8 @@ do_pass:
new_insn = new_prog;
fp = prog;
- if (new_insn) {
- *new_insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_CTX, BPF_REG_ARG1);
- }
+ if (new_insn)
+ *new_insn = BPF_MOV64_REG(BPF_REG_CTX, BPF_REG_ARG1);
new_insn++;
for (i = 0; i < len; fp++, i++) {
@@ -921,17 +894,16 @@ do_pass:
convert_bpf_extensions(fp, &insn))
break;
- insn->code = fp->code;
- insn->a_reg = BPF_REG_A;
- insn->x_reg = BPF_REG_X;
- insn->imm = fp->k;
+ *insn = BPF_RAW_INSN(fp->code, BPF_REG_A, BPF_REG_X, 0, fp->k);
break;
- /* Jump opcodes map as-is, but offsets need adjustment. */
- case BPF_JMP | BPF_JA:
- target = i + fp->k + 1;
- insn->code = fp->code;
-#define EMIT_JMP \
+ /* Jump transformation cannot use BPF block macros
+ * everywhere as offset calculation and target updates
+ * require a bit more work than the rest, i.e. jump
+ * opcodes map as-is, but offsets need adjustment.
+ */
+
+#define BPF_EMIT_JMP \
do { \
if (target >= len || target < 0) \
goto err; \
@@ -940,7 +912,10 @@ do_pass:
insn->off -= insn - tmp_insns; \
} while (0)
- EMIT_JMP;
+ case BPF_JMP | BPF_JA:
+ target = i + fp->k + 1;
+ insn->code = fp->code;
+ BPF_EMIT_JMP;
break;
case BPF_JMP | BPF_JEQ | BPF_K:
@@ -956,10 +931,7 @@ do_pass:
* immediate into tmp register and use it
* in compare insn.
*/
- insn->code = BPF_ALU | BPF_MOV | BPF_K;
- insn->a_reg = BPF_REG_TMP;
- insn->imm = fp->k;
- insn++;
+ *insn++ = BPF_MOV32_IMM(BPF_REG_TMP, fp->k);
insn->a_reg = BPF_REG_A;
insn->x_reg = BPF_REG_TMP;
@@ -975,7 +947,7 @@ do_pass:
if (fp->jf == 0) {
insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src;
target = i + fp->jt + 1;
- EMIT_JMP;
+ BPF_EMIT_JMP;
break;
}
@@ -983,116 +955,94 @@ do_pass:
if (fp->jt == 0 && BPF_OP(fp->code) == BPF_JEQ) {
insn->code = BPF_JMP | BPF_JNE | bpf_src;
target = i + fp->jf + 1;
- EMIT_JMP;
+ BPF_EMIT_JMP;
break;
}
/* Other jumps are mapped into two insns: Jxx and JA. */
target = i + fp->jt + 1;
insn->code = BPF_JMP | BPF_OP(fp->code) | bpf_src;
- EMIT_JMP;
+ BPF_EMIT_JMP;
insn++;
insn->code = BPF_JMP | BPF_JA;
target = i + fp->jf + 1;
- EMIT_JMP;
+ BPF_EMIT_JMP;
break;
/* ldxb 4 * ([14] & 0xf) is remaped into 6 insns. */
case BPF_LDX | BPF_MSH | BPF_B:
/* tmp = A */
- *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_TMP, BPF_REG_A);
- insn++;
-
+ *insn++ = BPF_MOV64_REG(BPF_REG_TMP, BPF_REG_A);
/* A = BPF_R0 = *(u8 *) (skb->data + K) */
- *insn = BPF_LD_ABS(BPF_B, fp->k);
- insn++;
-
+ *insn++ = BPF_LD_ABS(BPF_B, fp->k);
/* A &= 0xf */
- *insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, 0xf);
- insn++;
-
+ *insn++ = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, 0xf);
/* A <<= 2 */
- *insn = BPF_ALU32_IMM(BPF_LSH, BPF_REG_A, 2);
- insn++;
-
+ *insn++ = BPF_ALU32_IMM(BPF_LSH, BPF_REG_A, 2);
/* X = A */
- *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_X, BPF_REG_A);
- insn++;
-
+ *insn++ = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A);
/* A = tmp */
- *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_A, BPF_REG_TMP);
+ *insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_TMP);
break;
/* RET_K, RET_A are remaped into 2 insns. */
case BPF_RET | BPF_A:
case BPF_RET | BPF_K:
- insn->code = BPF_ALU | BPF_MOV |
- (BPF_RVAL(fp->code) == BPF_K ?
- BPF_K : BPF_X);
- insn->a_reg = 0;
- insn->x_reg = BPF_REG_A;
- insn->imm = fp->k;
- insn++;
-
+ *insn++ = BPF_MOV32_RAW(BPF_RVAL(fp->code) == BPF_K ?
+ BPF_K : BPF_X, BPF_REG_0,
+ BPF_REG_A, fp->k);
*insn = BPF_EXIT_INSN();
break;
/* Store to stack. */
case BPF_ST:
case BPF_STX:
- insn->code = BPF_STX | BPF_MEM | BPF_W;
- insn->a_reg = BPF_REG_FP;
- insn->x_reg = fp->code == BPF_ST ?
- BPF_REG_A : BPF_REG_X;
- insn->off = -(BPF_MEMWORDS - fp->k) * 4;
+ *insn = BPF_STX_MEM(BPF_W, BPF_REG_FP, BPF_CLASS(fp->code) ==
+ BPF_ST ? BPF_REG_A : BPF_REG_X,
+ -(BPF_MEMWORDS - fp->k) * 4);
break;
/* Load from stack. */
case BPF_LD | BPF_MEM:
case BPF_LDX | BPF_MEM:
- insn->code = BPF_LDX | BPF_MEM | BPF_W;
- insn->a_reg = BPF_CLASS(fp->code) == BPF_LD ?
- BPF_REG_A : BPF_REG_X;
- insn->x_reg = BPF_REG_FP;
- insn->off = -(BPF_MEMWORDS - fp->k) * 4;
+ *insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ?
+ BPF_REG_A : BPF_REG_X, BPF_REG_FP,
+ -(BPF_MEMWORDS - fp->k) * 4);
break;
/* A = K or X = K */
case BPF_LD | BPF_IMM:
case BPF_LDX | BPF_IMM:
- insn->code = BPF_ALU | BPF_MOV | BPF_K;
- insn->a_reg = BPF_CLASS(fp->code) == BPF_LD ?
- BPF_REG_A : BPF_REG_X;
- insn->imm = fp->k;
+ *insn = BPF_MOV32_IMM(BPF_CLASS(fp->code) == BPF_LD ?
+ BPF_REG_A : BPF_REG_X, fp->k);
break;
/* X = A */
case BPF_MISC | BPF_TAX:
- *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_X, BPF_REG_A);
+ *insn = BPF_MOV64_REG(BPF_REG_X, BPF_REG_A);
break;
/* A = X */
case BPF_MISC | BPF_TXA:
- *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_A, BPF_REG_X);
+ *insn = BPF_MOV64_REG(BPF_REG_A, BPF_REG_X);
break;
/* A = skb->len or X = skb->len */
case BPF_LD | BPF_W | BPF_LEN:
case BPF_LDX | BPF_W | BPF_LEN:
- insn->code = BPF_LDX | BPF_MEM | BPF_W;
- insn->a_reg = BPF_CLASS(fp->code) == BPF_LD ?
- BPF_REG_A : BPF_REG_X;
- insn->x_reg = BPF_REG_CTX;
- insn->off = offsetof(struct sk_buff, len);
+ *insn = BPF_LDX_MEM(BPF_W, BPF_CLASS(fp->code) == BPF_LD ?
+ BPF_REG_A : BPF_REG_X, BPF_REG_CTX,
+ offsetof(struct sk_buff, len));
break;
- /* access seccomp_data fields */
+ /* Access seccomp_data fields. */
case BPF_LDX | BPF_ABS | BPF_W:
/* A = *(u32 *) (ctx + K) */
*insn = BPF_LDX_MEM(BPF_W, BPF_REG_A, BPF_REG_CTX, fp->k);
break;
+ /* Unkown instruction. */
default:
goto err;
}
@@ -1101,7 +1051,6 @@ do_pass:
if (new_prog)
memcpy(new_insn, tmp_insns,
sizeof(*insn) * (insn - tmp_insns));
-
new_insn += insn - tmp_insns;
}
@@ -1116,7 +1065,6 @@ do_pass:
new_flen = new_insn - new_prog;
if (pass > 2)
goto err;
-
goto do_pass;
}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.