From: Andy Lutomirski <luto@kernel.org>
To: x86@kernel.org
Cc: LKML <linux-kernel@vger.kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Andy Lutomirski <luto@kernel.org>
Subject: [PATCH v3 03/11] x86/dumpstack: Remove unnecessary range check fetching opcode bytes
Date: Thu, 4 Mar 2021 11:05:56 -0800 [thread overview]
Message-ID: <b2872f67cbfc649229ddc4e6c3418ec03d3707e3.1614884673.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1614884673.git.luto@kernel.org>
copy_from_user_nmi() validates that the pointer is in the user range,
so there is no need for an extra check in copy_code().
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/kernel/dumpstack.c | 6 ------
1 file changed, 6 deletions(-)
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 299c20f0a38b..55cf3c8325c6 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -81,12 +81,6 @@ static int copy_code(struct pt_regs *regs, u8 *buf, unsigned long src,
/* The user space code from other tasks cannot be accessed. */
if (regs != task_pt_regs(current))
return -EPERM;
- /*
- * Make sure userspace isn't trying to trick us into dumping kernel
- * memory by pointing the userspace instruction pointer at it.
- */
- if (__chk_range_not_ok(src, nbytes, TASK_SIZE_MAX))
- return -EINVAL;
/*
* Even if named copy_from_user_nmi() this can be invoked from
--
2.29.2
next prev parent reply other threads:[~2021-03-04 19:07 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-04 19:05 [PATCH v3 00/11] kentry: A stable bugfix and a bunch of improvements Andy Lutomirski
2021-03-04 19:05 ` [PATCH v3 01/11] x86/entry: Fix entry/exit mismatch on failed fast 32-bit syscalls Andy Lutomirski
2021-03-05 10:16 ` [tip: x86/urgent] " tip-bot2 for Andy Lutomirski
2021-03-06 10:44 ` tip-bot2 for Andy Lutomirski
2021-03-06 12:18 ` tip-bot2 for Andy Lutomirski
2021-03-04 19:05 ` [PATCH v3 02/11] kentry: Rename irqentry to kentry Andy Lutomirski
2021-03-08 9:45 ` Mark Rutland
2021-03-04 19:05 ` Andy Lutomirski [this message]
2021-03-04 19:05 ` [PATCH v3 04/11] x86/kthread,dumpstack: Set task_pt_regs->cs.RPL=3 for kernel threads Andy Lutomirski
2021-03-04 20:19 ` Ira Weiny
2021-03-04 19:05 ` [PATCH v3 05/11] x86/entry: Convert ret_from_fork to C Andy Lutomirski
2021-03-05 0:55 ` Brian Gerst
2021-03-04 19:05 ` [PATCH v3 06/11] kentry: Simplify the common syscall API Andy Lutomirski
2021-03-08 9:49 ` Mark Rutland
2021-03-04 19:06 ` [PATCH v3 07/11] kentry: Make entry/exit_to_user_mode() arm64-only Andy Lutomirski
2021-03-08 10:06 ` Mark Rutland
2021-03-14 1:18 ` Andy Lutomirski
2021-03-04 19:06 ` [PATCH v3 08/11] entry: Make CONFIG_DEBUG_ENTRY available outside x86 Andy Lutomirski
2021-03-08 10:13 ` Mark Rutland
2021-03-29 11:50 ` Sven Schnelle
2021-03-04 19:06 ` [PATCH v3 09/11] kentry: Add debugging checks for proper kentry API usage Andy Lutomirski
2021-03-04 19:06 ` [PATCH v3 10/11] kentry: Check that syscall entries and syscall exits match Andy Lutomirski
2021-03-04 19:06 ` [PATCH v3 11/11] kentry: Verify kentry state in instrumentation_begin/end() Andy Lutomirski
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