| From | Kamal Mostafa <> | Subject | [PATCH 4.2.y-ckt 211/273] x86/mpx: Fix off-by-one comparison with nr_registers | Date | Mon, 7 Mar 2016 14:50:02 -0800 |
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4.2.8-ckt5 -stable review patch. If anyone has any objections, please let me know.
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From: Colin Ian King <colin.king@canonical.com>
commit 9bf148cb0812595bfdf5100bd2c07e9bec9c6ef5 upstream.
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 <colin.king@canonical.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Link: http://lkml.kernel.org/r/1456512931-3388-1-git-send-email-colin.king@canonical.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- 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 27f8393..b77009c 100644 --- a/arch/x86/mm/mpx.c +++ b/arch/x86/mm/mpx.c @@ -160,7 +160,7 @@ 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; } -- 2.7.0
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