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129 lines
4.9 KiB
129 lines
4.9 KiB
From 3f90090e70a5fa81bced17792fe08d9c46324da9 Mon Sep 17 00:00:00 2001
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From: "Ted X. Toth" <txtoth@flycast.org>
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Date: Thu, 13 Oct 2022 12:58:26 -0700
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Subject: [PATCH] manager: use target process context to set socket context
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Use target process context to set socket context when using SELinuxContextFromNet
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not systemd's context. Currently when using the SELinuxContextFromNet option for
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a socket activated services, systemd calls getcon_raw which returns init_t and
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uses the resulting context to compute the context to be passed to the
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setsockcreatecon call. A socket of type init_t is created and listened on and
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this means that SELinux policy cannot be written to control which processes
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(SELinux types) can connect to the socket since the ref policy allows all
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'types' to connect to sockets of the type init_t. When security accessors see
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that any process can connect to a socket this raises serious concerns. I have
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spoken with SELinux contributors in person and on the mailing list and the
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consensus is that the best solution is to use the target executables context
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when computing the sockets context in all cases.
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[zjs review/comment:
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This removes the branch that was added in 16115b0a7b7cdf08fb38084d857d572d8a9088dc.
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16115b0a7b7cdf08fb38084d857d572d8a9088dc did two things: it had the branch here
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in 'socket_determine_selinux_label()' and a code in 'exec_child()' to call
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'label_get_child_mls_label(socket_fd, command->path, &label)'.
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Before this patch, the flow was:
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'''
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mac_selinux_get_child_mls_label:
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peercon = getpeercon_raw(socket_fd);
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if (!exec_label)
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exec_label = getfilecon_raw(exe);
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socket_open_fds:
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if (params->selinux_context_net) #
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label = mac_selinux_get_our_label(); # this part is removed
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else #
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label = mac_selinux_get_create_label_from_exe(path);
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socket_address_listen_in_cgroup(s, &p->address, label);
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exec_child():
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exec_context = mac_selinux_get_child_mls_label(fd, executable, context->selinux_context);
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setexeccon(exec_context);
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'''
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]
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(cherry picked from commit 29dbc62d74f7b7881dc3136e68e03a03ea055b36)
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Resolves: #2136738
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---
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src/core/socket.c | 58 ++++++++++++++++++++---------------------------
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1 file changed, 24 insertions(+), 34 deletions(-)
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diff --git a/src/core/socket.c b/src/core/socket.c
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index d1ca0a07c5..8aa5463b25 100644
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--- a/src/core/socket.c
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+++ b/src/core/socket.c
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@@ -1434,47 +1434,37 @@ static int socket_determine_selinux_label(Socket *s, char **ret) {
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assert(s);
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assert(ret);
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- if (s->selinux_context_from_net) {
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- /* If this is requested, get label from the network label */
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-
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- r = mac_selinux_get_our_label(ret);
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- if (r == -EOPNOTSUPP)
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- goto no_label;
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-
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- } else {
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- /* Otherwise, get it from the executable we are about to start */
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- r = socket_instantiate_service(s);
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- if (r < 0)
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- return r;
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+ r = socket_instantiate_service(s);
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+ if (r < 0)
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+ return r;
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- if (!UNIT_ISSET(s->service))
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- goto no_label;
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- service = SERVICE(UNIT_DEREF(s->service));
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+ if (!UNIT_ISSET(s->service))
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+ goto no_label;
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+ service = SERVICE(UNIT_DEREF(s->service));
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- exec_context = service->exec_context.selinux_context;
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- if (exec_context) {
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- char *con;
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+ exec_context = service->exec_context.selinux_context;
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+ if (exec_context) {
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+ char *con;
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- con = strdup(exec_context);
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- if (!con)
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- return -ENOMEM;
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+ con = strdup(exec_context);
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+ if (!con)
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+ return -ENOMEM;
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- *ret = TAKE_PTR(con);
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- return 0;
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- }
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+ *ret = TAKE_PTR(con);
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+ return 0;
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+ }
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- c = service->exec_command[SERVICE_EXEC_START];
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- if (!c)
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- goto no_label;
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+ c = service->exec_command[SERVICE_EXEC_START];
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+ if (!c)
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+ goto no_label;
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- r = chase_symlinks(c->path, service->exec_context.root_directory, CHASE_PREFIX_ROOT, &path);
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- if (r < 0)
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- goto no_label;
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+ r = chase_symlinks(c->path, service->exec_context.root_directory, CHASE_PREFIX_ROOT, &path);
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+ if (r < 0)
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+ goto no_label;
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- r = mac_selinux_get_create_label_from_exe(path, ret);
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- if (IN_SET(r, -EPERM, -EOPNOTSUPP))
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- goto no_label;
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- }
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+ r = mac_selinux_get_create_label_from_exe(path, ret);
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+ if (IN_SET(r, -EPERM, -EOPNOTSUPP))
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+ goto no_label;
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return r;
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