From 9bf148cb0812595bfdf5100bd2c07e9bec9c6ef5 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Fri, 26 Feb 2016 18:55:31 +0000 Subject: [PATCH] x86/mpx: Fix off-by-one comparison with nr_registers In the unlikely event that regno == nr_registers then we get an array overrun on regoff because the invalid register check is currently off-by-one. Fix this with a check that regno is >= nr_registers instead. Detected with static analysis using CoverityScan. Fixes: fcc7ffd67991 "x86, mpx: Decode MPX instruction to get bound violation information" Signed-off-by: Colin Ian King Acked-by: Dave Hansen Cc: Borislav Petkov Cc: "Kirill A . Shutemov" Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1456512931-3388-1-git-send-email-colin.king@canonical.com Signed-off-by: Thomas Gleixner --- arch/x86/mm/mpx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c index b2fd67da1701..ef05755a1900 100644 --- a/arch/x86/mm/mpx.c +++ b/arch/x86/mm/mpx.c @@ -123,7 +123,7 @@ static int get_reg_offset(struct insn *insn, struct pt_regs *regs, break; } - if (regno > nr_registers) { + if (regno >= nr_registers) { WARN_ONCE(1, "decoded an instruction with an invalid register"); return -EINVAL; } -- 2.20.1