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    Subject[PATCH 4.14 092/193] audit: fix a memory leak bug
    Date
    [ Upstream commit 70c4cf17e445264453bc5323db3e50aa0ac9e81f ]

    In audit_rule_change(), audit_data_to_entry() is firstly invoked to
    translate the payload data to the kernel's rule representation. In
    audit_data_to_entry(), depending on the audit field type, an audit tree may
    be created in audit_make_tree(), which eventually invokes kmalloc() to
    allocate the tree. Since this tree is a temporary tree, it will be then
    freed in the following execution, e.g., audit_add_rule() if the message
    type is AUDIT_ADD_RULE or audit_del_rule() if the message type is
    AUDIT_DEL_RULE. However, if the message type is neither AUDIT_ADD_RULE nor
    AUDIT_DEL_RULE, i.e., the default case of the switch statement, this
    temporary tree is not freed.

    To fix this issue, only allocate the tree when the type is AUDIT_ADD_RULE
    or AUDIT_DEL_RULE.

    Signed-off-by: Wenwen Wang <wang6495@umn.edu>
    Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
    Signed-off-by: Paul Moore <paul@paul-moore.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    kernel/auditfilter.c | 12 +++++++-----
    1 file changed, 7 insertions(+), 5 deletions(-)

    diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
    index 8dd4063647c2c..215c6e1ee026f 100644
    --- a/kernel/auditfilter.c
    +++ b/kernel/auditfilter.c
    @@ -1094,22 +1094,24 @@ int audit_rule_change(int type, int seq, void *data, size_t datasz)
    int err = 0;
    struct audit_entry *entry;

    - entry = audit_data_to_entry(data, datasz);
    - if (IS_ERR(entry))
    - return PTR_ERR(entry);
    -
    switch (type) {
    case AUDIT_ADD_RULE:
    + entry = audit_data_to_entry(data, datasz);
    + if (IS_ERR(entry))
    + return PTR_ERR(entry);
    err = audit_add_rule(entry);
    audit_log_rule_change("add_rule", &entry->rule, !err);
    break;
    case AUDIT_DEL_RULE:
    + entry = audit_data_to_entry(data, datasz);
    + if (IS_ERR(entry))
    + return PTR_ERR(entry);
    err = audit_del_rule(entry);
    audit_log_rule_change("remove_rule", &entry->rule, !err);
    break;
    default:
    - err = -EINVAL;
    WARN_ON(1);
    + return -EINVAL;
    }

    if (err || type == AUDIT_DEL_RULE) {
    --
    2.20.1


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