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Message-ID: <CAHC9VhTwyNsW5xVNsb+jXhgoLL86daZL1cWG9d+DVB0dQJAgMQ@mail.gmail.com>
Date: Wed, 2 Oct 2019 17:12:01 -0400
From: Paul Moore <paul@...l-moore.com>
To: Kees Cook <keescook@...omium.org>
Cc: linux-kernel@...r.kernel.org,
Jérémie Galarneau <jeremie.galarneau@...icios.com>,
s.mesoraca16@...il.com, viro@...iv.linux.org.uk, dan.carpenter@...cle.com,
akpm@...ux-foundation.org, Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
kernel-hardening@...ts.openwall.com, linux-audit@...hat.com,
Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH v2] audit: Report suspicious O_CREAT usage
On Tue, Oct 1, 2019 at 12:48 PM Kees Cook <keescook@...omium.org> wrote:
>
> This renames the very specific audit_log_link_denied() to
> audit_log_path_denied() and adds the AUDIT_* type as an argument. This
> allows for the creation of the new AUDIT_ANOM_CREAT that can be used to
> report the fifo/regular file creation restrictions that were introduced
> in commit 30aba6656f61 ("namei: allow restricted O_CREAT of FIFOs and
> regular files"). Additionally further clarifies the existing
> "operations" strings.
>
> Signed-off-by: Kees Cook <keescook@...omium.org>
> ---
> v2:
> - fix build failure typo in CONFIG_AUDIT=n case
> - improve operations naming (paul)
> ---
> fs/namei.c | 8 ++++++--
> include/linux/audit.h | 5 +++--
> include/uapi/linux/audit.h | 1 +
> kernel/audit.c | 11 ++++++-----
> 4 files changed, 16 insertions(+), 9 deletions(-)
Thanks for the update, but I think we need another respin, see below.
> diff --git a/fs/namei.c b/fs/namei.c
> index 671c3c1a3425..2d5d245ae723 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -925,7 +925,7 @@ static inline int may_follow_link(struct nameidata *nd)
> return -ECHILD;
>
> audit_inode(nd->name, nd->stack[0].link.dentry, 0);
> - audit_log_link_denied("follow_link");
> + audit_log_path_denied(AUDIT_ANOM_LINK, "sticky_follow_link");
Maybe I should have been more clear in the last patch thread, but my
suggested name change was only for the new records you are adding; we
don't want to change the operation/op names for existing records. In
the above change, "follow_link" should stay "follow_link".
> @@ -993,7 +993,7 @@ static int may_linkat(struct path *link)
> if (safe_hardlink_source(inode) || inode_owner_or_capable(inode))
> return 0;
>
> - audit_log_link_denied("linkat");
> + audit_log_path_denied(AUDIT_ANOM_LINK, "unowned_linkat");
See above, this should stay as "linkat".
> @@ -1031,6 +1031,10 @@ static int may_create_in_sticky(struct dentry * const dir,
> (dir->d_inode->i_mode & 0020 &&
> ((sysctl_protected_fifos >= 2 && S_ISFIFO(inode->i_mode)) ||
> (sysctl_protected_regular >= 2 && S_ISREG(inode->i_mode))))) {
> + const char *operation = S_ISFIFO(inode->i_mode) ?
> + "sticky_create_fifo" :
> + "sticky_create_regular";
> + audit_log_path_denied(AUDIT_ANOM_CREAT, operation);
This is a new record, so this is fine. Thanks for changing this.
--
paul moore
www.paul-moore.com
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