summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
Diffstat
-rw-r--r--include/linux/filter.h44
-rw-r--r--net/core/filter.c215
2 files changed, 145 insertions, 114 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h
index b042d1db127f..ed1efab10b8f 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -40,16 +40,47 @@
/* Placeholder/dummy for 0 */
#define BPF_0 0
+/* Register numbers */
+enum {
+ BPF_REG_0 = 0,
+ BPF_REG_1,
+ BPF_REG_2,
+ BPF_REG_3,
+ BPF_REG_4,
+ BPF_REG_5,
+ BPF_REG_6,
+ BPF_REG_7,
+ BPF_REG_8,
+ BPF_REG_9,
+ BPF_REG_10,
+ __MAX_BPF_REG,
+};
+
/* BPF has 10 general purpose 64-bit registers and stack frame. */
-#define MAX_BPF_REG 11
+#define MAX_BPF_REG __MAX_BPF_REG
+
+/* ArgX, context and stack frame pointer register positions. Note,
+ * Arg1, Arg2, Arg3, etc are used as argument mappings of function
+ * calls in BPF_CALL instruction.
+ */
+#define BPF_REG_ARG1 BPF_REG_1
+#define BPF_REG_ARG2 BPF_REG_2
+#define BPF_REG_ARG3 BPF_REG_3
+#define BPF_REG_ARG4 BPF_REG_4
+#define BPF_REG_ARG5 BPF_REG_5
+#define BPF_REG_CTX BPF_REG_6
+#define BPF_REG_FP BPF_REG_10
+
+/* Additional register mappings for converted user programs. */
+#define BPF_REG_A BPF_REG_0
+#define BPF_REG_X BPF_REG_7
+#define BPF_REG_TMP BPF_REG_8
/* BPF program can access up to 512 bytes of stack space. */
#define MAX_BPF_STACK 512
-/* Arg1, context and stack frame pointer register positions. */
-#define ARG1_REG 1
-#define CTX_REG 6
-#define FP_REG 10
+/* Macro to invoke filter function. */
+#define SK_RUN_FILTER(filter, ctx) (*filter->bpf_func)(ctx, filter->insnsi)
struct sock_filter_int {
__u8 code; /* opcode */
@@ -100,9 +131,6 @@ static inline unsigned int sk_filter_size(unsigned int proglen)
#define sk_filter_proglen(fprog) \
(fprog->len * sizeof(fprog->filter[0]))
-#define SK_RUN_FILTER(filter, ctx) \
- (*filter->bpf_func)(ctx, filter->insnsi)
-
int sk_filter(struct sock *sk, struct sk_buff *skb);
u32 sk_run_filter_int_seccomp(const struct seccomp_data *ctx,
diff --git a/net/core/filter.c b/net/core/filter.c
index a1784e95b049..c93ca8d66f37 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -45,6 +45,27 @@
#include <linux/seccomp.h>
#include <linux/if_vlan.h>
+/* Registers */
+#define R0 regs[BPF_REG_0]
+#define R1 regs[BPF_REG_1]
+#define R2 regs[BPF_REG_2]
+#define R3 regs[BPF_REG_3]
+#define R4 regs[BPF_REG_4]
+#define R5 regs[BPF_REG_5]
+#define R6 regs[BPF_REG_6]
+#define R7 regs[BPF_REG_7]
+#define R8 regs[BPF_REG_8]
+#define R9 regs[BPF_REG_9]
+#define R10 regs[BPF_REG_10]
+
+/* Named registers */
+#define A regs[insn->a_reg]
+#define X regs[insn->x_reg]
+#define FP regs[BPF_REG_FP]
+#define ARG1 regs[BPF_REG_ARG1]
+#define CTX regs[BPF_REG_CTX]
+#define K insn->imm
+
/* No hurry in this branch
*
* Exported for the bpf jit load helper.
@@ -122,13 +143,6 @@ noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
return 0;
}
-/* Register mappings for user programs. */
-#define A_REG 0
-#define X_REG 7
-#define TMP_REG 8
-#define ARG2_REG 2
-#define ARG3_REG 3
-
/**
* __sk_run_filter - run a filter on a given context
* @ctx: buffer to run the filter on
@@ -142,17 +156,6 @@ unsigned int __sk_run_filter(void *ctx, const struct sock_filter_int *insn)
{
u64 stack[MAX_BPF_STACK / sizeof(u64)];
u64 regs[MAX_BPF_REG], tmp;
- void *ptr;
- int off;
-
-#define K insn->imm
-#define A regs[insn->a_reg]
-#define X regs[insn->x_reg]
-#define R0 regs[0]
-
-#define CONT ({insn++; goto select_insn; })
-#define CONT_JMP ({insn++; goto select_insn; })
-
static const void *jumptable[256] = {
[0 ... 255] = &&default_label,
/* Now overwrite non-defaults ... */
@@ -246,11 +249,18 @@ unsigned int __sk_run_filter(void *ctx, const struct sock_filter_int *insn)
DL(LD, IND, B),
#undef DL
};
+ void *ptr;
+ int off;
- regs[FP_REG] = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
- regs[ARG1_REG] = (u64) (unsigned long) ctx;
- regs[A_REG] = 0;
- regs[X_REG] = 0;
+#define CONT ({ insn++; goto select_insn; })
+#define CONT_JMP ({ insn++; goto select_insn; })
+
+ FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
+ ARG1 = (u64) (unsigned long) ctx;
+
+ /* Register for user BPF programs need to be reset first. */
+ regs[BPF_REG_A] = 0;
+ regs[BPF_REG_X] = 0;
select_insn:
goto *jumptable[insn->code];
@@ -375,8 +385,7 @@ select_insn:
/* Function call scratches R1-R5 registers, preserves R6-R9,
* and stores return value into R0.
*/
- R0 = (__bpf_call_base + insn->imm)(regs[1], regs[2], regs[3],
- regs[4], regs[5]);
+ R0 = (__bpf_call_base + insn->imm)(R1, R2, R3, R4, R5);
CONT;
/* JMP */
@@ -500,7 +509,7 @@ select_insn:
load_word:
/* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are only
* appearing in the programs where ctx == skb. All programs
- * keep 'ctx' in regs[CTX_REG] == R6, sk_convert_filter()
+ * keep 'ctx' in regs[BPF_REG_CTX] == R6, sk_convert_filter()
* saves it in R6, internal BPF verifier will check that
* R6 == ctx.
*
@@ -556,13 +565,6 @@ load_byte:
/* If we ever reach this, we have a bug somewhere. */
WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
return 0;
-#undef CONT_JMP
-#undef CONT
-
-#undef R0
-#undef X
-#undef A
-#undef K
}
u32 sk_run_filter_int_seccomp(const struct seccomp_data *ctx,
@@ -594,14 +596,14 @@ static unsigned int pkt_type_offset(void)
return -1;
}
-static u64 __skb_get_pay_offset(u64 ctx, u64 A, u64 X, u64 r4, u64 r5)
+static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
{
struct sk_buff *skb = (struct sk_buff *)(long) ctx;
return __skb_get_poff(skb);
}
-static u64 __skb_get_nlattr(u64 ctx, u64 A, u64 X, u64 r4, u64 r5)
+static u64 __skb_get_nlattr(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
{
struct sk_buff *skb = (struct sk_buff *)(long) ctx;
struct nlattr *nla;
@@ -612,17 +614,17 @@ static u64 __skb_get_nlattr(u64 ctx, u64 A, u64 X, u64 r4, u64 r5)
if (skb->len < sizeof(struct nlattr))
return 0;
- if (A > skb->len - sizeof(struct nlattr))
+ if (a > skb->len - sizeof(struct nlattr))
return 0;
- nla = nla_find((struct nlattr *) &skb->data[A], skb->len - A, X);
+ nla = nla_find((struct nlattr *) &skb->data[a], skb->len - a, x);
if (nla)
return (void *) nla - (void *) skb->data;
return 0;
}
-static u64 __skb_get_nlattr_nest(u64 ctx, u64 A, u64 X, u64 r4, u64 r5)
+static u64 __skb_get_nlattr_nest(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
{
struct sk_buff *skb = (struct sk_buff *)(long) ctx;
struct nlattr *nla;
@@ -633,27 +635,27 @@ static u64 __skb_get_nlattr_nest(u64 ctx, u64 A, u64 X, u64 r4, u64 r5)
if (skb->len < sizeof(struct nlattr))
return 0;
- if (A > skb->len - sizeof(struct nlattr))
+ if (a > skb->len - sizeof(struct nlattr))
return 0;
- nla = (struct nlattr *) &skb->data[A];
- if (nla->nla_len > skb->len - A)
+ nla = (struct nlattr *) &skb->data[a];
+ if (nla->nla_len > skb->len - a)
return 0;
- nla = nla_find_nested(nla, X);
+ nla = nla_find_nested(nla, x);
if (nla)
return (void *) nla - (void *) skb->data;
return 0;
}
-static u64 __get_raw_cpu_id(u64 ctx, u64 A, u64 X, u64 r4, u64 r5)
+static u64 __get_raw_cpu_id(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
{
return raw_smp_processor_id();
}
/* note that this only generates 32-bit random numbers */
-static u64 __get_random_u32(u64 ctx, u64 A, u64 X, u64 r4, u64 r5)
+static u64 __get_random_u32(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
{
return (u64)prandom_u32();
}
@@ -668,28 +670,28 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, protocol) != 2);
insn->code = BPF_LDX | BPF_MEM | BPF_H;
- insn->a_reg = A_REG;
- insn->x_reg = CTX_REG;
+ insn->a_reg = BPF_REG_A;
+ insn->x_reg = BPF_REG_CTX;
insn->off = offsetof(struct sk_buff, protocol);
insn++;
/* A = ntohs(A) [emitting a nop or swap16] */
insn->code = BPF_ALU | BPF_END | BPF_FROM_BE;
- insn->a_reg = A_REG;
+ insn->a_reg = BPF_REG_A;
insn->imm = 16;
break;
case SKF_AD_OFF + SKF_AD_PKTTYPE:
insn->code = BPF_LDX | BPF_MEM | BPF_B;
- insn->a_reg = A_REG;
- insn->x_reg = CTX_REG;
+ insn->a_reg = BPF_REG_A;
+ insn->x_reg = BPF_REG_CTX;
insn->off = pkt_type_offset();
if (insn->off < 0)
return false;
insn++;
insn->code = BPF_ALU | BPF_AND | BPF_K;
- insn->a_reg = A_REG;
+ insn->a_reg = BPF_REG_A;
insn->imm = PKT_TYPE_MAX;
break;
@@ -699,13 +701,13 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
insn->code = BPF_LDX | BPF_MEM | BPF_DW;
else
insn->code = BPF_LDX | BPF_MEM | BPF_W;
- insn->a_reg = TMP_REG;
- insn->x_reg = CTX_REG;
+ insn->a_reg = BPF_REG_TMP;
+ insn->x_reg = BPF_REG_CTX;
insn->off = offsetof(struct sk_buff, dev);
insn++;
insn->code = BPF_JMP | BPF_JNE | BPF_K;
- insn->a_reg = TMP_REG;
+ insn->a_reg = BPF_REG_TMP;
insn->imm = 0;
insn->off = 1;
insn++;
@@ -716,8 +718,8 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4);
BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, type) != 2);
- insn->a_reg = A_REG;
- insn->x_reg = TMP_REG;
+ 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;
@@ -732,8 +734,8 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
insn->code = BPF_LDX | BPF_MEM | BPF_W;
- insn->a_reg = A_REG;
- insn->x_reg = CTX_REG;
+ insn->a_reg = BPF_REG_A;
+ insn->x_reg = BPF_REG_CTX;
insn->off = offsetof(struct sk_buff, mark);
break;
@@ -741,8 +743,8 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
insn->code = BPF_LDX | BPF_MEM | BPF_W;
- insn->a_reg = A_REG;
- insn->x_reg = CTX_REG;
+ insn->a_reg = BPF_REG_A;
+ insn->x_reg = BPF_REG_CTX;
insn->off = offsetof(struct sk_buff, hash);
break;
@@ -750,8 +752,8 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, queue_mapping) != 2);
insn->code = BPF_LDX | BPF_MEM | BPF_H;
- insn->a_reg = A_REG;
- insn->x_reg = CTX_REG;
+ insn->a_reg = BPF_REG_A;
+ insn->x_reg = BPF_REG_CTX;
insn->off = offsetof(struct sk_buff, queue_mapping);
break;
@@ -760,8 +762,8 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
insn->code = BPF_LDX | BPF_MEM | BPF_H;
- insn->a_reg = A_REG;
- insn->x_reg = CTX_REG;
+ insn->a_reg = BPF_REG_A;
+ insn->x_reg = BPF_REG_CTX;
insn->off = offsetof(struct sk_buff, vlan_tci);
insn++;
@@ -769,16 +771,16 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
if (fp->k == SKF_AD_OFF + SKF_AD_VLAN_TAG) {
insn->code = BPF_ALU | BPF_AND | BPF_K;
- insn->a_reg = A_REG;
+ insn->a_reg = BPF_REG_A;
insn->imm = ~VLAN_TAG_PRESENT;
} else {
insn->code = BPF_ALU | BPF_RSH | BPF_K;
- insn->a_reg = A_REG;
+ insn->a_reg = BPF_REG_A;
insn->imm = 12;
insn++;
insn->code = BPF_ALU | BPF_AND | BPF_K;
- insn->a_reg = A_REG;
+ insn->a_reg = BPF_REG_A;
insn->imm = 1;
}
break;
@@ -790,20 +792,20 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
case SKF_AD_OFF + SKF_AD_RANDOM:
/* arg1 = ctx */
insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = ARG1_REG;
- insn->x_reg = CTX_REG;
+ insn->a_reg = BPF_REG_ARG1;
+ insn->x_reg = BPF_REG_CTX;
insn++;
/* arg2 = A */
insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = ARG2_REG;
- insn->x_reg = A_REG;
+ insn->a_reg = BPF_REG_ARG2;
+ insn->x_reg = BPF_REG_A;
insn++;
/* arg3 = X */
insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = ARG3_REG;
- insn->x_reg = X_REG;
+ insn->a_reg = BPF_REG_ARG3;
+ insn->x_reg = BPF_REG_X;
insn++;
/* Emit call(ctx, arg2=A, arg3=X) */
@@ -829,8 +831,8 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
case SKF_AD_OFF + SKF_AD_ALU_XOR_X:
insn->code = BPF_ALU | BPF_XOR | BPF_X;
- insn->a_reg = A_REG;
- insn->x_reg = X_REG;
+ insn->a_reg = BPF_REG_A;
+ insn->x_reg = BPF_REG_X;
break;
default:
@@ -880,7 +882,7 @@ int sk_convert_filter(struct sock_filter *prog, int len,
u8 bpf_src;
BUILD_BUG_ON(BPF_MEMWORDS * sizeof(u32) > MAX_BPF_STACK);
- BUILD_BUG_ON(FP_REG + 1 != MAX_BPF_REG);
+ BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
if (len <= 0 || len >= BPF_MAXINSNS)
return -EINVAL;
@@ -897,8 +899,8 @@ do_pass:
if (new_insn) {
new_insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- new_insn->a_reg = CTX_REG;
- new_insn->x_reg = ARG1_REG;
+ new_insn->a_reg = BPF_REG_CTX;
+ new_insn->x_reg = BPF_REG_ARG1;
}
new_insn++;
@@ -948,8 +950,8 @@ do_pass:
break;
insn->code = fp->code;
- insn->a_reg = A_REG;
- insn->x_reg = X_REG;
+ insn->a_reg = BPF_REG_A;
+ insn->x_reg = BPF_REG_X;
insn->imm = fp->k;
break;
@@ -983,16 +985,16 @@ do_pass:
* in compare insn.
*/
insn->code = BPF_ALU | BPF_MOV | BPF_K;
- insn->a_reg = TMP_REG;
+ insn->a_reg = BPF_REG_TMP;
insn->imm = fp->k;
insn++;
- insn->a_reg = A_REG;
- insn->x_reg = TMP_REG;
+ insn->a_reg = BPF_REG_A;
+ insn->x_reg = BPF_REG_TMP;
bpf_src = BPF_X;
} else {
- insn->a_reg = A_REG;
- insn->x_reg = X_REG;
+ insn->a_reg = BPF_REG_A;
+ insn->x_reg = BPF_REG_X;
insn->imm = fp->k;
bpf_src = BPF_SRC(fp->code);
}
@@ -1027,33 +1029,33 @@ do_pass:
/* ldxb 4 * ([14] & 0xf) is remaped into 6 insns. */
case BPF_LDX | BPF_MSH | BPF_B:
insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = TMP_REG;
- insn->x_reg = A_REG;
+ insn->a_reg = BPF_REG_TMP;
+ insn->x_reg = BPF_REG_A;
insn++;
insn->code = BPF_LD | BPF_ABS | BPF_B;
- insn->a_reg = A_REG;
+ insn->a_reg = BPF_REG_A;
insn->imm = fp->k;
insn++;
insn->code = BPF_ALU | BPF_AND | BPF_K;
- insn->a_reg = A_REG;
+ insn->a_reg = BPF_REG_A;
insn->imm = 0xf;
insn++;
insn->code = BPF_ALU | BPF_LSH | BPF_K;
- insn->a_reg = A_REG;
+ insn->a_reg = BPF_REG_A;
insn->imm = 2;
insn++;
insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = X_REG;
- insn->x_reg = A_REG;
+ insn->a_reg = BPF_REG_X;
+ insn->x_reg = BPF_REG_A;
insn++;
insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = A_REG;
- insn->x_reg = TMP_REG;
+ insn->a_reg = BPF_REG_A;
+ insn->x_reg = BPF_REG_TMP;
break;
/* RET_K, RET_A are remaped into 2 insns. */
@@ -1063,7 +1065,7 @@ do_pass:
(BPF_RVAL(fp->code) == BPF_K ?
BPF_K : BPF_X);
insn->a_reg = 0;
- insn->x_reg = A_REG;
+ insn->x_reg = BPF_REG_A;
insn->imm = fp->k;
insn++;
@@ -1074,8 +1076,9 @@ do_pass:
case BPF_ST:
case BPF_STX:
insn->code = BPF_STX | BPF_MEM | BPF_W;
- insn->a_reg = FP_REG;
- insn->x_reg = fp->code == BPF_ST ? A_REG : X_REG;
+ 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;
break;
@@ -1084,8 +1087,8 @@ do_pass:
case BPF_LDX | BPF_MEM:
insn->code = BPF_LDX | BPF_MEM | BPF_W;
insn->a_reg = BPF_CLASS(fp->code) == BPF_LD ?
- A_REG : X_REG;
- insn->x_reg = FP_REG;
+ BPF_REG_A : BPF_REG_X;
+ insn->x_reg = BPF_REG_FP;
insn->off = -(BPF_MEMWORDS - fp->k) * 4;
break;
@@ -1094,22 +1097,22 @@ do_pass:
case BPF_LDX | BPF_IMM:
insn->code = BPF_ALU | BPF_MOV | BPF_K;
insn->a_reg = BPF_CLASS(fp->code) == BPF_LD ?
- A_REG : X_REG;
+ BPF_REG_A : BPF_REG_X;
insn->imm = fp->k;
break;
/* X = A */
case BPF_MISC | BPF_TAX:
insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = X_REG;
- insn->x_reg = A_REG;
+ insn->a_reg = BPF_REG_X;
+ insn->x_reg = BPF_REG_A;
break;
/* A = X */
case BPF_MISC | BPF_TXA:
insn->code = BPF_ALU64 | BPF_MOV | BPF_X;
- insn->a_reg = A_REG;
- insn->x_reg = X_REG;
+ insn->a_reg = BPF_REG_A;
+ insn->x_reg = BPF_REG_X;
break;
/* A = skb->len or X = skb->len */
@@ -1117,16 +1120,16 @@ do_pass:
case BPF_LDX | BPF_W | BPF_LEN:
insn->code = BPF_LDX | BPF_MEM | BPF_W;
insn->a_reg = BPF_CLASS(fp->code) == BPF_LD ?
- A_REG : X_REG;
- insn->x_reg = CTX_REG;
+ BPF_REG_A : BPF_REG_X;
+ insn->x_reg = BPF_REG_CTX;
insn->off = offsetof(struct sk_buff, len);
break;
/* access seccomp_data fields */
case BPF_LDX | BPF_ABS | BPF_W:
insn->code = BPF_LDX | BPF_MEM | BPF_W;
- insn->a_reg = A_REG;
- insn->x_reg = CTX_REG;
+ insn->a_reg = BPF_REG_A;
+ insn->x_reg = BPF_REG_CTX;
insn->off = fp->k;
break;
generated by cgit v1.2.3 (git 2.25.1) at 2024-10-16 18:45:07 +0000