Messages in this thread Patch in this message | | | From | David Laight <> | Subject | RE: Using memcpy instead of copy_to_user. xprtrdma code. | Date | Tue, 25 Jan 2022 22:21:31 +0000 |
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From: Aleksey Senin <aleksey-linux-kernel@senin.name> > Sent: 25 January 2022 18:04 > > This specific patch - - implements using memcpy instead of > copy_to_user. Why is it considered to be safe in this specific case? > All readings about how to copy data are mentioning to use > copy_to_user/copy_from_user. Why use direct copy here? What prevents > the kernel from failure if the page is not present or doesn't have > required access rights? > > @@ -103,8 +102,8 @@ static int read_reset_stat(struct ctl_table > *table, int write, > len -= *ppos; > if (len > *lenp) > len = *lenp; > - if (len && copy_to_user(buffer, str_buf, len)) > - return -EFAULT; > + if (len) > + memcpy(buffer, str_buf, len); > > Reference to the specific patch in the services of commits: > https://lkml.org/lkml/2020/4/17/60
Read the commit message.
> > Commit itself: > 32927393dc1ccd60fb2bdc05b9e8e88753761469
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