Re: [PATCH v2 4/5] audit: fix filename matching in __audit_inode() and __audit_inode_child()

Richard Guy Briggs
2015-01-22T16:04:05Z

On 15/01/22, Paul Moore wrote:
> In all likelihood there were some subtle, and perhaps not so subtle,
> bugs with filename matching in audit_inode() and audit_inode_child()
> for some time, however, recent changes to the audit filename code have
> definitely broken the filename matching code. The breakage could
> result in duplicate filenames in the audit log and other odd audit
> record entries. This patch fixes the filename matching code and
> restores some sanity to the filename audit records.
>
> CC: viro@zeniv.linux.org.uk
> CC: linux-fsdevel@vger.kernel.org
> Signed-off-by: Paul Moore <pmoore@redhat.com>

Noted change to use the iterator instead of the reference in the inode check.

Reviewed-by: Richard Guy Briggs <rgb@redhat.com>

> ---
> kernel/auditsc.c | 34 +++++++++++++++++++++++++---------
> 1 file changed, 25 insertions(+), 9 deletions(-)
>
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index c967ffc..c54b5f0 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -1846,6 +1846,7 @@ void __audit_inode(struct filename *name, const struct dentry *dentry,
> /* The struct filename _must_ have a populated ->name */
> BUG_ON(!name->name);
> #endif
> +
> /*
> * If we have a pointer to an audit_names entry already, then we can
> * just use it directly if the type is correct.
> @@ -1863,7 +1864,17 @@ void __audit_inode(struct filename *name, const struct dentry *dentry,
> }
>
> list_for_each_entry_reverse(n, &context->names_list, list) {
> - if (!n->name || strcmp(n->name->name, name->name))
> + if (n->ino) {
> + /* valid inode number, use that for the comparison */
> + if (n->ino != inode->i_ino ||
> + n->dev != inode->i_sb->s_dev)
> + continue;
> + } else if (n->name) {
> + /* inode number has not been set, check the name */
> + if (strcmp(n->name->name, name->name))
> + continue;
> + } else
> + /* no inode and no name (?!) ... this is odd ... */
> continue;
>
> /* match the correct record type */
> @@ -1931,11 +1942,16 @@ void __audit_inode_child(const struct inode *parent,
>
> /* look for a parent entry first */
> list_for_each_entry(n, &context->names_list, list) {
> - if (!n->name || n->type != AUDIT_TYPE_PARENT)
> + if (!n->name ||
> + (n->type != AUDIT_TYPE_PARENT &&
> + n->type != AUDIT_TYPE_UNKNOWN))
> continue;
>
> - if (n->ino == parent->i_ino &&
> - !audit_compare_dname_path(dname, n->name->name, n->name_len)) {
> + if (n->ino == parent->i_ino && n->dev == parent->i_sb->s_dev &&
> + !audit_compare_dname_path(dname,
> + n->name->name, n->name_len)) {
> + if (n->type == AUDIT_TYPE_UNKNOWN)
> + n->type = AUDIT_TYPE_PARENT;
> found_parent = n;
> break;
> }
> @@ -1944,11 +1960,8 @@ void __audit_inode_child(const struct inode *parent,
> /* is there a matching child entry? */
> list_for_each_entry(n, &context->names_list, list) {
> /* can only match entries that have a name */
> - if (!n->name || n->type != type)
> - continue;
> -
> - /* if we found a parent, make sure this one is a child of it */
> - if (found_parent && (n->name != found_parent->name))
> + if (!n->name ||
> + (n->type != type && n->type != AUDIT_TYPE_UNKNOWN))
> continue;
>
> if (!strcmp(dname, n->name->name) ||
> @@ -1956,6 +1969,8 @@ void __audit_inode_child(const struct inode *parent,
> found_parent ?
> found_parent->name_len :
> AUDIT_NAME_FULL)) {
> + if (n->type == AUDIT_TYPE_UNKNOWN)
> + n->type = type;
> found_child = n;
> break;
> }
> @@ -1984,6 +1999,7 @@ void __audit_inode_child(const struct inode *parent,
> found_child->name_put = false;
> }
> }
> +
> if (inode)
> audit_copy_inode(found_child, dentry, inode);
> else
>

- RGB

--
Richard Guy Briggs <rbriggs@redhat.com>
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545