Messages in this thread Patch in this message | | | From | Andy Lutomirski <> | Subject | [PATCH v4 1/9] x86/dumpstack: Remove unnecessary range check fetching opcode bytes | Date | Wed, 17 Mar 2021 11:12:40 -0700 |
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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
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