* Re: + bsdacct-switch-credentials-for-writing-to-the-accounting-file.patch added to -mm tree
2009-08-21 15:57 ` + bsdacct-switch-credentials-for-writing-to-the-accounting-file.patch added to -mm tree Serge E. Hallyn
@ 2009-08-24 1:34 ` James Morris
0 siblings, 0 replies; 2+ messages in thread
From: James Morris @ 2009-08-24 1:34 UTC (permalink / raw)
To: Serge E. Hallyn; +Cc: linux-kernel, mm-commits, mschmidt, dhowells, sds
Applied to
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6#next
On Fri, 21 Aug 2009, Serge E. Hallyn wrote:
> Quoting akpm@linux-foundation.org (akpm@linux-foundation.org):
> >
> > The patch titled
> > bsdacct: switch credentials for writing to the accounting file
> > has been added to the -mm tree. Its filename is
> > bsdacct-switch-credentials-for-writing-to-the-accounting-file.patch
> >
> > Before you just go and hit "reply", please:
> > a) Consider who else should be cc'ed
> > b) Prefer to cc a suitable mailing list as well
> > c) Ideally: find the original patch on the mailing list and do a
> > reply-to-all to that, adding suitable additional cc's
> >
> > *** Remember to use Documentation/SubmitChecklist when testing your code ***
> >
> > See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
> > out what to do about this
> >
> > The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
> >
> > ------------------------------------------------------
> > Subject: bsdacct: switch credentials for writing to the accounting file
> > From: Michal Schmidt <mschmidt@redhat.com>
> >
> > When process accounting is enabled, every exiting process writes a log to
> > the account file. In addition, every once in a while one of the exiting
> > processes checks whether there's enough free space for the log.
> >
> > SELinux policy may or may not allow the exiting process to stat the fs.
> > So unsuspecting processes start generating AVC denials just because
> > someone enabled process accounting.
> >
> > For these filesystem operations, the exiting process's credentials should
> > be temporarily switched to that of the process which enabled accounting,
> > because it's really that process which wanted to have the accounting
> > information logged.
> >
> > Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
> > Acked-by: David Howells <dhowells@redhat.com>
>
> Acked-by: Serge Hallyn <serue@us.ibm.com>
>
> > Cc: James Morris <jmorris@namei.org>
> > Cc: Serge Hallyn <serue@us.ibm.com>
> > Cc: Stephen Smalley <sds@tycho.nsa.gov>
> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > ---
> >
> > kernel/acct.c | 8 +++++++-
> > 1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff -puN kernel/acct.c~bsdacct-switch-credentials-for-writing-to-the-accounting-file kernel/acct.c
> > --- a/kernel/acct.c~bsdacct-switch-credentials-for-writing-to-the-accounting-file
> > +++ a/kernel/acct.c
> > @@ -491,13 +491,17 @@ static void do_acct_process(struct bsd_a
> > u64 run_time;
> > struct timespec uptime;
> > struct tty_struct *tty;
> > + const struct cred *orig_cred;
> > +
> > + /* Perform file operations on behalf of whoever enabled accounting */
> > + orig_cred = override_creds(file->f_cred);
> >
> > /*
> > * First check to see if there is enough free_space to continue
> > * the process accounting system.
> > */
> > if (!check_free_space(acct, file))
> > - return;
> > + goto out;
> >
> > /*
> > * Fill the accounting struct with the needed info as recorded
> > @@ -578,6 +582,8 @@ static void do_acct_process(struct bsd_a
> > sizeof(acct_t), &file->f_pos);
> > current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim;
> > set_fs(fs);
> > +out:
> > + revert_creds(orig_cred);
> > }
> >
> > /**
> > _
> >
> > Patches currently in -mm which might be from mschmidt@redhat.com are
> >
> > bsdacct-switch-credentials-for-writing-to-the-accounting-file.patch
> >
> > --
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--
James Morris
<jmorris@namei.org>
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