[PATCH 2/2] use use SEEK_MAX to validate user lseek arguments

["Chris Snook" <csnook@redhat.com>]

From: Chris Snook <csnook@redhat.com>

Add SEEK_MAX and use it to validate lseek arguments from userspace.

Signed-off-by: Chris Snook <csnook@redhat.com>
--
diff -urp b/fs/read_write.c c/fs/read_write.c
--- b/fs/read_write.c	2007-02-20 16:48:39.000000000 -0500
+++ c/fs/read_write.c	2007-02-20 16:55:46.000000000 -0500
@@ -139,7 +139,7 @@ asmlinkage off_t sys_lseek(unsigned int
 		goto bad;

 	retval = -EINVAL;
-	if (origin <= 2) {
+	if (origin <= SEEK_MAX) {
 		loff_t res = vfs_llseek(file, offset, origin);
 		retval = res;
 		if (res != (loff_t)retval)
@@ -166,7 +166,7 @@ asmlinkage long sys_llseek(unsigned int
 		goto bad;

 	retval = -EINVAL;
-	if (origin > 2)
+	if (origin > SEEK_MAX)
 		goto out_putf;

 	offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low,
diff -urp b/include/linux/fs.h c/include/linux/fs.h
--- b/include/linux/fs.h	2007-02-20 14:49:46.000000000 -0500
+++ c/include/linux/fs.h	2007-02-20 16:54:30.000000000 -0500
@@ -30,6 +30,7 @@
 #define SEEK_SET	0	/* seek relative to beginning of file */
 #define SEEK_CUR	1	/* seek relative to current file position */
 #define SEEK_END	2	/* seek relative to end of file */
+#define SEEK_MAX	SEEK_END

 /* And dynamically-tunable limits and defaults: */
 struct files_stat_struct {

-
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