[v2.6.34-stable 110/213] x86, tls: Off by one limit check

[Paul Gortmaker]

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit 8f0750f19789cf352d7e24a6cc50f2ab1b4f1372 upstream.

These are used as offsets into an array of GDT_ENTRY_TLS_ENTRIES members
so GDT_ENTRY_TLS_ENTRIES is one past the end of the array.

Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20120324075250.GA28258@xxxxxxxxxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 arch/x86/kernel/tls.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/tls.c b/arch/x86/kernel/tls.c
index 6bb7b8579e70..bcfec2d23769 100644
--- a/arch/x86/kernel/tls.c
+++ b/arch/x86/kernel/tls.c
@@ -163,7 +163,7 @@ int regset_tls_get(struct task_struct *target, const struct user_regset *regset,
 {
 	const struct desc_struct *tls;
 
-	if (pos > GDT_ENTRY_TLS_ENTRIES * sizeof(struct user_desc) ||
+	if (pos >= GDT_ENTRY_TLS_ENTRIES * sizeof(struct user_desc) ||
 	    (pos % sizeof(struct user_desc)) != 0 ||
 	    (count % sizeof(struct user_desc)) != 0)
 		return -EINVAL;
@@ -198,7 +198,7 @@ int regset_tls_set(struct task_struct *target, const struct user_regset *regset,
 	struct user_desc infobuf[GDT_ENTRY_TLS_ENTRIES];
 	const struct user_desc *info;
 
-	if (pos > GDT_ENTRY_TLS_ENTRIES * sizeof(struct user_desc) ||
+	if (pos >= GDT_ENTRY_TLS_ENTRIES * sizeof(struct user_desc) ||
 	    (pos % sizeof(struct user_desc)) != 0 ||
 	    (count % sizeof(struct user_desc)) != 0)
 		return -EINVAL;
-- 
1.8.5.2

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