[PATCHv2 1/4] actual sys_indirect code

[PATCHv2 1/4] actual sys_indirect code

[Ulrich Drepper]

This is the actual architecture-independent part of the system call
implementation.

 b/include/linux/indirect.h |   13 ++++++++++++
 b/include/linux/syscalls.h |    3 ++
 b/kernel/Makefile          |    2 -
 b/kernel/indirect.c        |   46 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/sched.h      |    4 +++
 5 files changed, 67 insertions(+), 1 deletion(-)

--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -80,6 +80,7 @@ struct sched_param {
 #include <linux/rcupdate.h>
 #include <linux/futex.h>
 #include <linux/rtmutex.h>
+#include <linux/indirect.h>
 
 #include <linux/time.h>
 #include <linux/param.h>
@@ -1174,6 +1175,9 @@ struct task_struct {
 	int make_it_fail;
 #endif
 	struct prop_local_single dirties;
+
+	/* Additional system call parameters.  */
+	union indirect_params indirect_params;
 };
 
 /*
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 61def7c..614ff36 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -54,6 +54,7 @@ struct compat_stat;
 struct compat_timeval;
 struct robust_list_head;
 struct getcpu_cache;
+struct indirect_registers;
 
 #include <linux/types.h>
 #include <linux/aio_abi.h>
@@ -611,6 +612,8 @@ asmlinkage long sys_timerfd(int ufd, int clockid, int flags,
 			    const struct itimerspec __user *utmr);
 asmlinkage long sys_eventfd(unsigned int count);
 asmlinkage long sys_fallocate(int fd, int mode, loff_t offset, loff_t len);
+asmlinkage long sys_indirect(struct indirect_registers __user *userregs,
+			     void __user *userparams, size_t paramslen);
 
 int kernel_execve(const char *filename, char *const argv[], char *const envp[]);
 
diff --git a/kernel/Makefile b/kernel/Makefile
index f60afe7..ef82be0 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -9,7 +9,7 @@ obj-y     = sched.o fork.o exec_domain.o panic.o printk.o profile.o \
 	    rcupdate.o extable.o params.o posix-timers.o \
 	    kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
 	    hrtimer.o rwsem.o latency.o nsproxy.o srcu.o \
-	    utsname.o notifier.o
+	    utsname.o notifier.o indirect.o
 
 obj-$(CONFIG_SYSCTL) += sysctl_check.o
 obj-$(CONFIG_STACKTRACE) += stacktrace.o
diff --git a/net/socket.c b/net/socket.c
index 74784df..e3a3a04 100644
--- /dev/null	2007-09-23 16:36:38.465394704 -0700
+++ b/include/linux/indirect.h	2007-11-14 17:53:18.000000000 -0800
@@ -0,0 +1,13 @@
+#ifndef _LINUX_INDIRECT_H
+#define _LINUX_INDIRECT_H
+
+#include <asm/indirect.h>
+
+
+union indirect_params {
+  struct {
+    int flags;
+  } file_flags;
+};
+
+#endif
--- /dev/null	2007-09-23 16:36:38.465394704 -0700
+++ b/kernel/indirect.c	2007-11-15 09:46:34.000000000 -0800
@@ -0,0 +1,46 @@
+#include <linux/sched.h>
+#include <linux/uaccess.h>
+#include <linux/unistd.h>
+#include <asm/asm-offsets.h>
+
+
+long sys_indirect(struct indirect_registers __user *userregs,
+		  void __user *userparams, size_t paramslen)
+{
+	struct indirect_registers regs;
+	long result;
+
+	if (copy_from_user(&regs, userregs, sizeof(regs)))
+		return -EFAULT;
+
+	switch (INDIRECT_SYSCALL (&regs))
+	{
+#ifdef __NR_accept
+	case __NR_accept:
+#endif
+#ifdef __NR_socketpair
+	case __NR_socketpair:
+#endif
+#ifdef __NR_socket
+	case __NR_socket:
+#endif
+#ifdef __NR_socketcall
+	case __NR_socketcall:
+#endif
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	if (paramslen > sizeof(union indirect_params))
+		return -EINVAL;
+	if (copy_from_user(&current->indirect_params, userparams, paramslen))
+		return -EFAULT;
+
+	result = CALL_INDIRECT(&regs);
+
+	memset(&current->indirect_params, '\0', paramslen);
+
+	return result;
+}

Re: [PATCHv2 1/4] actual sys_indirect code

[Eric Dumazet]

Ulrich Drepper a écrit :
> This is the actual architecture-independent part of the system call
> implementation.
> 

> +
> +long sys_indirect(struct indirect_registers __user *userregs,
> +		  void __user *userparams, size_t paramslen)
> +{
> +	struct indirect_registers regs;
> +	long result;
> +
> +	if (copy_from_user(&regs, userregs, sizeof(regs)))
> +		return -EFAULT;
> +
> +	switch (INDIRECT_SYSCALL (&regs))
> +	{
> +#ifdef __NR_accept
> +	case __NR_accept:
> +#endif
> +#ifdef __NR_socketpair
> +	case __NR_socketpair:
> +#endif
> +#ifdef __NR_socket
> +	case __NR_socket:
> +#endif
> +#ifdef __NR_socketcall
> +	case __NR_socketcall:
> +#endif
> +		break;
> +
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	if (paramslen > sizeof(union indirect_params))
> +		return -EINVAL;
> +	if (copy_from_user(&current->indirect_params, userparams, paramslen))

Here, you should clear current->indirect_params before returning -EFAULT
                 {
                 memset(&current->indirect_params, 0, paramslen);
> +		return -EFAULT;
                 }
copy_from_user could do a partial copy (so dirty first bytes of 
indirect_params) and all furthers calls to socket()/open() and so on could be 
broken.

> +
> +	result = CALL_INDIRECT(&regs);
> +
> +	memset(&current->indirect_params, '\0', paramslen);
> +
> +	return result;
> +}
> -