kernel: usercopy functions

kernel-src/include/kernel/scheduler.h

@@ -51,6 +51,7 @@ typedef struct thread_t {
 	int wakeupreason;
 	bool shouldexit;
 	void *kernelarg;
+	context_t *usercopyctx;
 	struct {
 		spinlock_t lock;
 		stack_t stack;

kernel-src/include/kernel/sock.h

@@ -5,6 +5,7 @@
 #include <kernel/vfs.h>
 #include <mutex.h>
 #include <kernel/poll.h>
+#include <kernel/usercopy.h>
 
 #define SOCKET_STATE_UNBOUND 0
 #define SOCKET_STATE_BOUND 1
@@ -93,11 +94,16 @@ static inline int sock_addrtoabiaddr(int socktype, sockaddr_t *sockaddr, abisock
 }
 
 static inline int sock_copymsghdr(msghdr_t *khdr, msghdr_t *uhdr) {
-	memcpy(khdr, uhdr, sizeof(msghdr_t));
+	if (usercopy_fromuser(khdr, uhdr, sizeof(msghdr_t)))
+		return EFAULT;
+
 	iovec_t *iovectmp = alloc(sizeof(iovec_t) * khdr->iovcount);
 	if (iovectmp == NULL)
 		return ENOMEM;
-	memcpy(iovectmp, khdr->iov, sizeof(iovec_t) * khdr->iovcount);
+
+	if (usercopy_fromuser(iovectmp, khdr->iov, sizeof(iovec_t) * khdr->iovcount))
+		return EFAULT;
+
 	khdr->iov = iovectmp;
 
 	if (khdr->addr) {
@@ -106,7 +112,12 @@ static inline int sock_copymsghdr(msghdr_t *khdr, msghdr_t *uhdr) {
 			free(iovectmp);
 			return ENOMEM;
 		}
-		memcpy(addrtmp, khdr->addr, khdr->addrlen);
+
+		if (usercopy_fromuser(addrtmp, khdr->addr, khdr->addrlen)) {
+			free(iovectmp);
+			return EFAULT;
+		}
+
 		khdr->addr = addrtmp;
 	}
 

kernel-src/include/kernel/syscalls.h

@@ -6,6 +6,7 @@
 #include <kernel/vfs.h>
 #include <kernel/file.h>
 #include <kernel/scheduler.h>
+#include <kernel/usercopy.h>
 
 typedef struct {
 	uint64_t ret;

kernel-src/include/kernel/usercopy.h

@@ -0,0 +1,29 @@
+#ifndef _USERCOPY_H
+#define _USERCOPY_H
+
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+//IS_USER_ADDRESS(a) is provided by arch/mmu.h
+#include <arch/mmu.h>
+
+static inline int _usercopy_memcpy_wrapper(void *dst, void *src, size_t size) {
+	memcpy(dst, src, size);
+	return 0;
+}
+static inline int _usercopy_strlen_wrapper(void *str, size_t *size) {
+	*size = strlen(str);
+	return 0;
+}
+
+#define USERCOPY_POSSIBLY_FROM_USER(kernel, user, size) (IS_USER_ADDRESS(user) ? usercopy_fromuser(kernel, user, size) : _usercopy_memcpy_wrapper(kernel, user, size))
+#define USERCOPY_POSSIBLY_TO_USER(user, kernel, size) (IS_USER_ADDRESS(user) ? usercopy_touser(user, kernel, size) : _usercopy_memcpy_wrapper(user, kernel, size))
+#define USERCOPY_POSSIBLY_STRLEN_FROM_USER(user, sizep) (IS_USER_ADDRESS(user) ? usercopy_strlen(user, sizep) : _usercopy_strlen_wrapper(user, sizep))
+
+int usercopy_touser(void *user, void *kernel, size_t size);
+int usercopy_fromuser(void *kernel, void *user, size_t size);
+int usercopy_fromuseratomic32(uint32_t *user32, uint32_t *value);
+int usercopy_strlen(const char *, size_t *size);
+
+#endif