Add go_abi_internal.h

tap/tlstapper/bpf/golang_uprobes.c

@@ -39,6 +39,7 @@ A Quick Guide to Go's Assembler: https://go.googlesource.com/go/+/refs/heads/dev
 #include "include/logger_messages.h"
 #include "include/pids.h"
 #include "include/common.h"
+#include "include/go_abi_internal.h"
 
 
 SEC("uprobe/golang_crypto_tls_write")
@@ -51,9 +52,8 @@ static int golang_crypto_tls_write_uprobe(struct pt_regs *ctx) {
 
     struct ssl_info info = lookup_ssl_info(ctx, &ssl_write_context, pid_tgid);
 
-    // TODO: Try to make these architecture independent using macros
-    info.buffer_len = ctx->rcx;
-    info.buffer = (void*)ctx->rbx;
+    info.buffer_len = GO_ABI_INTERNAL_PT_REGS_R2(ctx);
+    info.buffer = (void*)GO_ABI_INTERNAL_PT_REGS_R4(ctx);
 
     long err = bpf_map_update_elem(&ssl_write_context, &pid_tgid, &info, BPF_ANY);
 
@@ -74,9 +74,9 @@ static int golang_crypto_tls_read_uprobe(struct pt_regs *ctx) {
         return 0;
     }
 
-    void* stack_addr = (void*)ctx->rsp;
+    void* stack_addr = (void*)GO_ABI_INTERNAL_PT_REGS_SP(ctx);
     __u64 data_p;
-    // Address at ctx->rsp + 0xd8 holds the data
+    // Address at stack pointer + 0xd8 holds the data (*fragile* and probably specific to x86-64)
     __u32 status = bpf_probe_read(&data_p, sizeof(data_p), stack_addr + 0xd8);
     if (status < 0) {
         log_error(ctx, LOG_ERROR_GOLANG_READ_READING_DATA_POINTER, pid_tgid, status, 0l);
@@ -85,8 +85,7 @@ static int golang_crypto_tls_read_uprobe(struct pt_regs *ctx) {
 
     struct ssl_info info = lookup_ssl_info(ctx, &ssl_read_context, pid_tgid);
 
-    // TODO: Try to make these architecture independent using macros
-    info.buffer_len = ctx->rcx;
+    info.buffer_len = GO_ABI_INTERNAL_PT_REGS_R2(ctx);
     info.buffer = (void*)data_p;
 
     long err = bpf_map_update_elem(&ssl_read_context, &pid_tgid, &info, BPF_ANY);

tap/tlstapper/bpf/include/go_abi_internal.h

@@ -0,0 +1,126 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+#ifndef __GOLANG_ABI_INTERNAL__
+#define __GOLANG_ABI_INTERNAL__
+
+/*
+Go internal ABI specification
+https://go.googlesource.com/go/+/refs/heads/master/src/cmd/compile/abi-internal.md
+*/
+
+/* Scan the ARCH passed in from ARCH env variable */
+#if defined(__TARGET_ARCH_x86)
+	#define bpf_target_x86
+	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_s390)
+	#define bpf_target_s390
+	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_arm)
+	#define bpf_target_arm
+	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_arm64)
+	#define bpf_target_arm64
+	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_mips)
+	#define bpf_target_mips
+	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_powerpc)
+	#define bpf_target_powerpc
+	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_sparc)
+	#define bpf_target_sparc
+	#define bpf_target_defined
+#else
+	#undef bpf_target_defined
+#endif
+
+/* Fall back to what the compiler says */
+#ifndef bpf_target_defined
+#if defined(__x86_64__)
+	#define bpf_target_x86
+#elif defined(__s390__)
+	#define bpf_target_s390
+#elif defined(__arm__)
+	#define bpf_target_arm
+#elif defined(__aarch64__)
+	#define bpf_target_arm64
+#elif defined(__mips__)
+	#define bpf_target_mips
+#elif defined(__powerpc__)
+	#define bpf_target_powerpc
+#elif defined(__sparc__)
+	#define bpf_target_sparc
+#endif
+#endif
+
+#if defined(bpf_target_x86)
+
+#ifdef __i386__
+
+/*
+https://go.googlesource.com/go/+/refs/heads/dev.regabi/src/cmd/compile/internal-abi.md#amd64-architecture
+https://github.com/golang/go/blob/go1.17.6/src/cmd/compile/internal/ssa/gen/AMD64Ops.go#L100
+*/
+#define GO_ABI_INTERNAL_PT_REGS_R1(x) ((x)->eax)
+#define GO_ABI_INTERNAL_PT_REGS_P2(x) ((x)->ecx)
+#define GO_ABI_INTERNAL_PT_REGS_P3(x) ((x)->edx)
+#define GO_ABI_INTERNAL_PT_REGS_P4(x) 0
+#define GO_ABI_INTERNAL_PT_REGS_P5(x) 0
+#define GO_ABI_INTERNAL_PT_REGS_P6(x) 0
+#define GO_ABI_INTERNAL_PT_REGS_SP(x) ((x)->esp)
+
+#else
+
+#define GO_ABI_INTERNAL_PT_REGS_R1(x) ((x)->rax)
+#define GO_ABI_INTERNAL_PT_REGS_R2(x) ((x)->rcx)
+#define GO_ABI_INTERNAL_PT_REGS_R3(x) ((x)->rdx)
+#define GO_ABI_INTERNAL_PT_REGS_R4(x) ((x)->rbx)
+#define GO_ABI_INTERNAL_PT_REGS_R5(x) ((x)->rbp)
+#define GO_ABI_INTERNAL_PT_REGS_R6(x) ((x)->rsi)
+#define GO_ABI_INTERNAL_PT_REGS_SP(x) ((x)->rsp)
+
+#endif
+
+#elif defined(bpf_target_arm)
+
+/*
+https://go.googlesource.com/go/+/refs/heads/master/src/cmd/compile/abi-internal.md#arm64-architecture
+https://github.com/golang/go/blob/go1.17.6/src/cmd/compile/internal/ssa/gen/ARM64Ops.go#L129-L131
+*/
+#define GO_ABI_INTERNAL_PT_REGS_R1(x) ((x)->uregs[0])
+#define GO_ABI_INTERNAL_PT_REGS_R2(x) ((x)->uregs[1])
+#define GO_ABI_INTERNAL_PT_REGS_R3(x) ((x)->uregs[2])
+#define GO_ABI_INTERNAL_PT_REGS_R4(x) ((x)->uregs[3])
+#define GO_ABI_INTERNAL_PT_REGS_R5(x) ((x)->uregs[4])
+#define GO_ABI_INTERNAL_PT_REGS_R6(x) ((x)->uregs[5])
+#define GO_ABI_INTERNAL_PT_REGS_SP(x) ((x)->uregs[14])
+
+#elif defined(bpf_target_arm64)
+
+/* arm64 provides struct user_pt_regs instead of struct pt_regs to userspace */
+struct pt_regs;
+#define PT_REGS_ARM64 const volatile struct user_pt_regs
+#define GO_ABI_INTERNAL_PT_REGS_R1(x) (((PT_REGS_ARM64 *)(x))->regs[0])
+#define GO_ABI_INTERNAL_PT_REGS_R2(x) (((PT_REGS_ARM64 *)(x))->regs[1])
+#define GO_ABI_INTERNAL_PT_REGS_R3(x) (((PT_REGS_ARM64 *)(x))->regs[2])
+#define GO_ABI_INTERNAL_PT_REGS_R4(x) (((PT_REGS_ARM64 *)(x))->regs[3])
+#define GO_ABI_INTERNAL_PT_REGS_R5(x) (((PT_REGS_ARM64 *)(x))->regs[4])
+#define GO_ABI_INTERNAL_PT_REGS_R6(x) (((PT_REGS_ARM64 *)(x))->regs[5])
+#define GO_ABI_INTERNAL_PT_REGS_SP(x) (((PT_REGS_ARM64 *)(x))->regs[30])
+
+#elif defined(bpf_target_powerpc)
+
+/*
+https://go.googlesource.com/go/+/refs/heads/master/src/cmd/compile/abi-internal.md#ppc64-architecture
+https://github.com/golang/go/blob/go1.17.6/src/cmd/compile/internal/ssa/gen/PPC64Ops.go#L125-L127
+*/
+#define GO_ABI_INTERNAL_PT_REGS_R1(x) ((x)->gpr[3])
+#define GO_ABI_INTERNAL_PT_REGS_R2(x) ((x)->gpr[4])
+#define GO_ABI_INTERNAL_PT_REGS_R3(x) ((x)->gpr[5])
+#define GO_ABI_INTERNAL_PT_REGS_R4(x) ((x)->gpr[6])
+#define GO_ABI_INTERNAL_PT_REGS_R5(x) ((x)->gpr[7])
+#define GO_ABI_INTERNAL_PT_REGS_R6(x) ((x)->gpr[8])
+#define GO_ABI_INTERNAL_PT_REGS_SP(x) ((x)->sp)
+
+#endif
+
+#endif