selinux: fix a double free in cond_read_node()/cond_read_list()

Clang static analysis reports this double free error

security/selinux/ss/conditional.c:139:2: warning: Attempt to free released memory [unix.Malloc]
        kfree(node->expr.nodes);
        ^~~~~~~~~~~~~~~~~~~~~~~

When cond_read_node fails, it calls cond_node_destroy which frees the
node but does not poison the entry in the node list.  So when it
returns to its caller cond_read_list, cond_read_list deletes the
partial list.  The latest entry in the list will be deleted twice.

So instead of freeing the node in cond_read_node, let list freeing in
code_read_list handle the freeing the problem node along with all of the
earlier nodes.

Because cond_read_node no longer does any error handling, the goto's
the error case are redundant.  Instead just return the error code.

Cc: [email protected]
Fixes: 60abd3181db2 ("selinux: convert cond_list to array")
Signed-off-by: Tom Rix <[email protected]>
Reviewed-by: Ondrej Mosnacek <[email protected]>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <[email protected]>

0 files changed, 0 insertions, 0 deletions