Commit 12aaa085 authored Aug 16, 2005 by Zachary Amsden Committed by Linus Torvalds Aug 16, 2005

[PATCH] i386 / desc_empty macro is incorrect



Chuck Ebbert noticed that the desc_empty macro is incorrect.  Fix it.

Thankfully, this is not used as a security check, but it can falsely
overwrite TLS segments with carefully chosen base / limits.  I do not
believe this is an issue in practice, but it is a kernel bug.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Chris Wright <chrisw@osdl.org>

[ x86-64 had the same problem, and the same fix. Linus ]

Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 5153f7e6

include/asm-i386/processor.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -29,7 +29,7 @@ struct desc_struct {
		};

		#define desc_empty(desc) \
		(!((desc)->a + (desc)->b))
		(!((desc)->a \| (desc)->b))

		#define desc_equal(desc1, desc2) \
		(((desc1)->a == (desc2)->a) && ((desc1)->b == (desc2)->b))

include/asm-x86_64/processor.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -32,7 +32,7 @@
		#define ID_MASK 0x00200000

		#define desc_empty(desc) \
		(!((desc)->a + (desc)->b))
		(!((desc)->a \| (desc)->b))

		#define desc_equal(desc1, desc2) \
		(((desc1)->a == (desc2)->a) && ((desc1)->b == (desc2)->b))