[patch 40/56] openmosix/mig_do_receive-size-checking.patch

[patch @num@/@total@] @name@ mig_do_receive* sanity check and NACK returns

This patch add the size checking on the mig_do_receive calls, and send NACKS
to deputy if packets seems corrupted for the remote system ... 

Affected functions are :
- mig_do_receive_mm
- mig_do_receive_vma
- mig_do_receive_fp
- mig_do_receive_page
- mig_do_receive_proc_context
Index: linux/hpc/migrecv.c
===================================================================
--- linux.orig/hpc/migrecv.c	2006-11-02 22:52:19.000000000 +0100
+++ linux/hpc/migrecv.c	2006-11-02 22:52:35.000000000 +0100
@@ -206,18 +206,28 @@
  * Description:
  *    Receives the process mmap info.
  **/
-KCOMD_NSTATIC void mig_do_receive_mm(task_t *p, struct kcom_pkt *pkt)
+KCOMD_NSTATIC int mig_do_receive_mm(task_t *p, struct kcom_pkt *pkt)
 {
 
 	OMDEBUG_MIG(2, "MIG_MM\n");
 
+
+	if (!pkt || sizeof(struct omp_mig_mm) != pkt->len) goto error_packet;
+
 	down_write(&p->mm->mmap_sem);
 	memcpy(&p->mm->start_code, pkt->data, pkt->len);
 	p->mm->exec_vm=0; /* MSD debug*/
 	up_write(&p->mm->mmap_sem);
 
+
+
 	kcom_send_ack(p, pkt);
+	return 0;
 
+error_packet:
+	printk(KERN_ERR "openMosix: (mm receive) packet NULL or size mismatched\n");
+	kcom_send_nack(p, pkt);
+	return -1;
 
 }
 EXPORT_SYMBOL_GPL(mig_do_receive_mm);
@@ -235,7 +245,9 @@
 	struct file *file = NULL;
 	extern asmlinkage long sys_madvise(unsigned long, size_t, int);
 
+	int ret = 0;
 
+	if (!pkt || sizeof(struct omp_mig_vma) != pkt->len) goto error_packet;
 
 	a = (struct omp_mig_vma *)pkt->data;
 
@@ -268,23 +280,29 @@
 							flags, a->vm_pgoff);
 		up_write(&p->mm->mmap_sem);
 
-		if (IS_ERR((const void *) result))
-			return PTR_ERR((const void *) result);
+		if (IS_ERR((const void *) result)) {
+			ret = PTR_ERR((const void *) result);
+			goto error_packet;
+		}
 
 		if (a->vm_flags & VM_READHINTMASK) {
+
 			int behavior = (a->vm_flags & VM_SEQ_READ)
 					? MADV_RANDOM
 					: MADV_SEQUENTIAL;
-			result=sys_madvise(a->vm_start, a->vm_size, behavior);
-			if (result)
-				kcom_send_nack(p, pkt);
-				return result;
-		}
 
+			ret=sys_madvise(a->vm_start, a->vm_size, behavior);
+			if (result) goto error_packet;
+
+		}
 
 	kcom_send_ack(p, pkt);
+	return ret;
 
-	return 0;
+error_packet:
+	printk(KERN_ERR "openMosix:(vma receive) packet NULL, size mismatched, or corrupted\n");
+	kcom_send_nack(p, pkt);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(mig_do_receive_vma);
 
@@ -302,7 +320,7 @@
 	struct mm_struct *mm = p->mm;
 	struct vm_area_struct *vma;
 	struct page *recv_page = NULL;
-	unsigned long addr;
+	unsigned long addr = 0xdeadc0de;
 	void *kmpage;
 
  	/*
@@ -310,15 +328,15 @@
  	Must be done from process context.
  	*/
 
-
+	if (!pkt || PAGE_SIZE != pkt->len) goto error_packet_size;
 
 	addr=pkt->addr;
 	vma = find_vma(mm, addr);
 	if (!vma) {
 		OMBUG("vma not found (addr: %p)\n", (void *) addr);
-		kcom_send_nack(p, pkt);
-		return -1;
+		goto error_packet;
 	}
+
 	recv_page=alloc_zeroed_user_highpage(vma, addr);
 	kmpage=kmap(recv_page);
 	memcpy(kmpage, pkt->data, pkt->len);
@@ -332,13 +350,19 @@
 	up_write(&mm->mmap_sem);
 
 	kcom_send_ack(p, pkt);
-
 	return 0;
 
-/*out:*/
+error_packet_size:
+	printk(KERN_ERR "openMosix: (page receive) packet NULL or size mismatch\n");
+
+error_packet:
+
 	printk(KERN_ERR "receive page failed at addr %p\n", (void *) addr);
 	OMBUG("receive page failed at addr %p\n", (void *) addr);
-	__free_page(recv_page);
+	if (recv_page) __free_page(recv_page);
+
+	kcom_send_nack(p, pkt);
+
 	return -1;
 
 }
@@ -355,16 +379,24 @@
 {
 	struct omp_mig_fp *fp;
 
+	if (!pkt || sizeof(struct omp_mig_fp) != pkt->len) goto error_packet;
+
 	fp=(void *)pkt->data;
 
 	OMDEBUG_MIG(2, "MIG_FP\n");
 	set_used_math();
+
 	arch_mig_receive_fp(p, fp);
 
 	kcom_send_ack(p, pkt);
 
 
 	return 0;
+
+error_packet:
+	printk(KERN_ERR "openMosix:(fp receive) packet NULL or size mismatched\n");
+	kcom_send_nack(p, pkt);
+	return -1;
 }
 
 /**
@@ -382,6 +414,8 @@
 {
 	struct omp_mig_task *m;
 
+	if (!pkt || sizeof(struct omp_mig_task) != pkt->len) goto error_packet;
+
 	m=(struct omp_mig_task *)pkt->data;
 
 	OMDEBUG_MIG(1, "MIG_TASK\n");
@@ -419,6 +453,11 @@
 	kcom_send_ack(p, pkt);
 
 	return 0;
+
+error_packet:
+	printk(KERN_ERR "openMosix:(proc_context receive) packet NULL or size mismatched\n");
+	kcom_send_nack(p, pkt);
+	return -1;
 }
 
 /**
@@ -461,9 +500,11 @@
 				switch (pkt->type & MIG_MASK) {
 
 					case MIG_MM:
-						mig_do_receive_mm(p, pkt);
+						ret =  mig_do_receive_mm(p, pkt);
 						list_del(&pkt->list);
 						kmem_cache_free(kcom_pkt_cachep, pkt);
+						if (ret)
+							return ret;
 						break;
 
 					case MIG_VMA: