From: Andy Lutomirski <luto@kernel.org>
To: x86@kernel.org
Cc: LKML <linux-kernel@vger.kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Brian Gerst <brgerst@gmail.com>,
Andy Lutomirski <luto@kernel.org>
Subject: [PATCH v4 1/9] x86/dumpstack: Remove unnecessary range check fetching opcode bytes
Date: Wed, 17 Mar 2021 11:12:40 -0700 [thread overview]
Message-ID: <0a7892ea337e40d464ff291b264e40fbcd39f4af.1616004689.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1616004689.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
--
2.30.2
next prev parent reply other threads:[~2021-03-17 18:13 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-17 18:12 [PATCH v4 0/9] kentry: A stable bugfix and a bunch of improvements Andy Lutomirski
2021-03-17 18:12 ` Andy Lutomirski [this message]
2021-03-17 18:12 ` [PATCH v4 2/9] x86/kthread,dumpstack: Set task_pt_regs->cs.RPL=3 for kernel threads Andy Lutomirski
2021-03-18 0:36 ` Josh Poimboeuf
2021-03-17 18:12 ` [PATCH v4 3/9] x86/entry: Convert ret_from_fork to C Andy Lutomirski
2021-03-18 0:38 ` Josh Poimboeuf
2021-03-19 16:05 ` Thomas Gleixner
2021-03-17 18:12 ` [PATCH v4 4/9] kentry: Simplify the common syscall API Andy Lutomirski
2021-03-19 16:09 ` Thomas Gleixner
2021-03-19 18:07 ` Thomas Gleixner
2021-03-17 18:12 ` [PATCH v4 5/9] kentry: Remove enter_from/exit_to_user_mode() Andy Lutomirski
2021-03-19 18:08 ` Thomas Gleixner
2021-03-17 18:12 ` [PATCH v4 6/9] entry: Make CONFIG_DEBUG_ENTRY available outside x86 Andy Lutomirski
2021-03-17 18:12 ` [PATCH v4 7/9] kentry: Add debugging checks for proper kentry API usage Andy Lutomirski
2021-03-19 16:17 ` Thomas Gleixner
2021-03-19 18:16 ` Thomas Gleixner
2021-03-17 18:12 ` [PATCH v4 8/9] kentry: Check that syscall entries and syscall exits match Andy Lutomirski
2021-03-17 18:12 ` [PATCH v4 9/9] kentry: Verify kentry state in instrumentation_begin/end() Andy Lutomirski
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