x86, tls: Off by one limit check

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@oracle.com>
Link: http://lkml.kernel.org/r/20120324075250.GA28258@elgon.mountain
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/kernel/tls.c b/arch/x86/kernel/tls.c
index 6bb7b8579e70e0a73a67ddcb9f69c01696bb6413..bcfec2d23769338f55a8f3c4f6c4be26d80230fc 100644 (file)
--- 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;