cosmopolitan/tool/build/lib/machine.h
Justine Tunney 7cf66bc161 Prevent Make from talking to public Internet
This change introduces the nointernet() function which may be called to
prevent a process and its descendants from communicating with publicly
routable Internet addresses. GNU Make has been modified to always call
this function. In the future Landlock Make will have a way to whitelist
subnets to override this behavior, or disable it entirely. Support is
available for Linux only. Our firewall does not require root access.

Calling nointernet() will return control to the caller inside a new
process that has a SECCOMP BPF filter installed, which traps network
related system calls. Your original process then becomes a permanent
ptrace() supervisor that monitors all processes and threads descending
from the returned child. Whenever a networking system call happens the
kernel will stop the process and wakes up the monitor, which then peeks
into the child memory to read the sockaddr_in to determine if it's ok.

The downside to doing this is that there can be only one supervisor at a
time using ptrace() on a process. So this firewall won't be enabled if
you run make under strace or inside gdb. It also makes testing tricky.
2022-08-12 21:51:39 -07:00

206 lines
5.4 KiB
C

#ifndef COSMOPOLITAN_TOOL_BUILD_LIB_MACHINE_H_
#define COSMOPOLITAN_TOOL_BUILD_LIB_MACHINE_H_
#include "libc/runtime/runtime.h"
#include "third_party/xed/x86.h"
#include "tool/build/lib/bits.h"
#include "tool/build/lib/fds.h"
#define kMachineHalt -1
#define kMachineDecodeError -2
#define kMachineUndefinedInstruction -3
#define kMachineSegmentationFault -4
#define kMachineExit -5
#define kMachineDivideError -6
#define kMachineFpuException -7
#define kMachineProtectionFault -8
#define kMachineSimdException -9
#define kMachineOverflow -10
#if !(__ASSEMBLER__ + __LINKER__ + 0)
COSMOPOLITAN_C_START_
struct Machine {
struct XedDecodedInst *xedd;
uint64_t ip;
uint8_t cs[8];
uint8_t ss[8];
uint64_t codevirt;
uint8_t *codehost;
uint32_t mode;
uint32_t flags;
uint32_t tlbindex;
uint32_t stashsize;
int64_t stashaddr;
int64_t readaddr;
int64_t writeaddr;
uint32_t readsize;
uint32_t writesize;
union {
uint8_t reg[16][8];
struct {
uint8_t ax[8];
uint8_t cx[8];
uint8_t dx[8];
uint8_t bx[8];
uint8_t sp[8];
uint8_t bp[8];
uint8_t si[8];
uint8_t di[8];
uint8_t r8[8];
uint8_t r9[8];
uint8_t r10[8];
uint8_t r11[8];
uint8_t r12[8];
uint8_t r13[8];
uint8_t r14[8];
uint8_t r15[8];
};
};
struct MachineTlb {
int64_t virt;
uint64_t entry;
} tlb[16];
struct MachineReal {
size_t i, n;
uint8_t *p;
} real;
uint64_t cr3;
uint8_t xmm[16][16];
uint8_t es[8];
uint8_t ds[8];
uint8_t fs[8];
uint8_t gs[8];
struct MachineFpu {
long double st[8];
union {
uint32_t cw;
struct {
unsigned im : 1; // invalid operation mask
unsigned dm : 1; // denormal operand mask
unsigned zm : 1; // zero divide mask
unsigned om : 1; // overflow mask
unsigned um : 1; // underflow mask
unsigned pm : 1; // precision mask
unsigned _p1 : 2; // reserved
unsigned pc : 2; // precision: 32,∅,64,80
unsigned rc : 2; // rounding: even,→-∞,→+∞,→0
};
};
union {
uint32_t sw;
struct {
unsigned ie : 1; // invalid operation
unsigned de : 1; // denormalized operand
unsigned ze : 1; // zero divide
unsigned oe : 1; // overflow
unsigned ue : 1; // underflow
unsigned pe : 1; // precision
unsigned sf : 1; // stack fault
unsigned es : 1; // exception summary status
unsigned c0 : 1; // condition 0
unsigned c1 : 1; // condition 1
unsigned c2 : 1; // condition 2
unsigned sp : 3; // top stack
unsigned c3 : 1; // condition 3
unsigned bf : 1; // busy flag
};
};
int tw;
int op;
int64_t ip;
int64_t dp;
} fpu;
struct MachineSse {
union {
uint32_t mxcsr;
struct {
unsigned ie : 1; // invalid operation flag
unsigned de : 1; // denormal flag
unsigned ze : 1; // divide by zero flag
unsigned oe : 1; // overflow flag
unsigned ue : 1; // underflow flag
unsigned pe : 1; // precision flag
unsigned daz : 1; // denormals are zeros
unsigned im : 1; // invalid operation mask
unsigned dm : 1; // denormal mask
unsigned zm : 1; // divide by zero mask
unsigned om : 1; // overflow mask
unsigned um : 1; // underflow mask
unsigned pm : 1; // precision mask
unsigned rc : 2; // rounding control
unsigned ftz : 1; // flush to zero
};
};
} sse;
uint64_t cr0;
uint64_t cr2;
uint64_t cr4;
uint64_t gdt_base;
uint64_t idt_base;
uint16_t gdt_limit;
uint16_t idt_limit;
uint32_t mxcsr;
struct MachineRealFree {
uint64_t i;
uint64_t n;
struct MachineRealFree *next;
} * realfree;
struct FreeList {
uint32_t i;
void *p[6];
} freelist;
struct MachineMemstat {
int freed;
int resizes;
int reserved;
int committed;
int allocated;
int reclaimed;
int pagetables;
} memstat;
int64_t brk;
int64_t bofram[2];
jmp_buf onhalt;
int64_t faultaddr;
bool dlab;
bool isfork;
bool ismetal;
struct MachineFds fds;
uint8_t stash[4096];
uint8_t icache[1024][40];
void (*onbinbase)(struct Machine *);
void (*onlongbranch)(struct Machine *);
void (*redraw)(void);
struct sigaction_bits sighand[28];
uint8_t sigmask[8];
int sig;
uint64_t siguc;
uint64_t sigfp;
struct {
int i, n;
struct {
int sig;
int code;
} p[64];
} signals;
} forcealign(64);
struct Machine *NewMachine(void) dontdiscard;
void FreeMachine(struct Machine *);
void ResetMem(struct Machine *);
void ResetCpu(struct Machine *);
void ResetTlb(struct Machine *);
void ResetInstructionCache(struct Machine *);
void LoadInstruction(struct Machine *);
void ExecuteInstruction(struct Machine *);
long AllocateLinearPage(struct Machine *);
long AllocateLinearPageRaw(struct Machine *);
int ReserveReal(struct Machine *, size_t);
int ReserveVirtual(struct Machine *, int64_t, size_t, uint64_t);
char *FormatPml4t(struct Machine *) dontdiscard;
int64_t FindVirtual(struct Machine *, int64_t, size_t);
int FreeVirtual(struct Machine *, int64_t, size_t);
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* COSMOPOLITAN_TOOL_BUILD_LIB_MACHINE_H_ */