[PATCH]: 4/4GB: Incorrect bound check in do_getname()

[PATCH]: 4/4GB: Incorrect bound check in do_getname()

[Kirill Korotaev]

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This patch fixes incorrect address range check in do_getname().
Theoretically this can lead to do_getname() failure on kernel
address space string on the TASK_SIZE boundary addresses when
4GB split is ON.

Signed-Off-By: Kirill Korotaev <dev@sw.ru>

Kirill

P.S. These 4GB split patches are against modified 2.6.8.1 kernel, but 
should be appliable to last Fedora kernels

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--- linux-2.6.8.1.test/fs/namei.c.tasksize	2003-08-28 21:38:41.000000000 +0400
+++ linux-2.6.8.1.test/fs/namei.c	2003-09-11 16:02:04.000000000 +0400
@@ -106,11 +106,12 @@
 	int retval;
 	unsigned long len = PATH_MAX;
 
-	if ((unsigned long) filename >= TASK_SIZE) {
-		if (!segment_eq(get_fs(), KERNEL_DS))
+	if (!segment_eq(get_fs(), KERNEL_DS)) {
+		if ((unsigned long) filename >= TASK_SIZE)
 			return -EFAULT;
-	} else if (TASK_SIZE - (unsigned long) filename < PATH_MAX)
-		len = TASK_SIZE - (unsigned long) filename;
+		if (TASK_SIZE - (unsigned long) filename < PATH_MAX)
+			len = TASK_SIZE - (unsigned long) filename;
+	}
 
 	retval = strncpy_from_user((char *)page, filename, len);
 	if (retval > 0) {