* [PATCH] x86/mpx: Fix off-by-one comparison with nr_registers
@ 2016-02-26 18:55 Colin King
2016-02-26 19:08 ` Dave Hansen
2016-02-26 21:15 ` [tip:x86/urgent] " tip-bot for Colin Ian King
0 siblings, 2 replies; 3+ messages in thread
From: Colin King @ 2016-02-26 18:55 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, H . Peter Anvin, x86, Dave Hansen,
Borislav Petkov, Kirill A . Shutemov
Cc: linux-kernel
From: Colin Ian King <colin.king@canonical.com>
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.
Signed-off-by: Colin Ian King <colin.king@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 5584397..8047687 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;
}
--
2.7.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] x86/mpx: Fix off-by-one comparison with nr_registers
2016-02-26 18:55 [PATCH] x86/mpx: Fix off-by-one comparison with nr_registers Colin King
@ 2016-02-26 19:08 ` Dave Hansen
2016-02-26 21:15 ` [tip:x86/urgent] " tip-bot for Colin Ian King
1 sibling, 0 replies; 3+ messages in thread
From: Dave Hansen @ 2016-02-26 19:08 UTC (permalink / raw)
To: Colin King, Thomas Gleixner, Ingo Molnar, H . Peter Anvin, x86,
Borislav Petkov, Kirill A . Shutemov
Cc: linux-kernel
On 02/26/2016 10:55 AM, Colin King wrote:
> 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.
Oh, the irony of an overrun in the MPX code! Thanks for catching this.
Acked-by: Dave Hansen <dave.hansen@intel.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* [tip:x86/urgent] x86/mpx: Fix off-by-one comparison with nr_registers
2016-02-26 18:55 [PATCH] x86/mpx: Fix off-by-one comparison with nr_registers Colin King
2016-02-26 19:08 ` Dave Hansen
@ 2016-02-26 21:15 ` tip-bot for Colin Ian King
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot for Colin Ian King @ 2016-02-26 21:15 UTC (permalink / raw)
To: linux-tip-commits
Cc: kirill.shutemov, bp, hpa, mingo, linux-kernel, colin.king, tglx,
dave.hansen
Commit-ID: 9bf148cb0812595bfdf5100bd2c07e9bec9c6ef5
Gitweb: http://git.kernel.org/tip/9bf148cb0812595bfdf5100bd2c07e9bec9c6ef5
Author: Colin Ian King <colin.king@canonical.com>
AuthorDate: Fri, 26 Feb 2016 18:55:31 +0000
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 26 Feb 2016 22:12:47 +0100
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 <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>
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 <tglx@linutronix.de>
---
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 b2fd67d..ef05755 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;
}
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2016-02-26 19:08 ` Dave Hansen
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