LSM: Better reporting of actual LSMs at boot

Enhance the details reported by "lsm.debug" in several ways:

- report contents of "security="
- report contents of "CONFIG_LSM"
- report contents of "lsm="
- report any early LSM details
- whitespace-align the output of similar phases for easier visual parsing
- change "disabled" to more accurate "skipped"
- explain what "skipped" and "ignored" mean in a parenthetical

Upgrade the "security= is ignored" warning from pr_info to pr_warn,
and include full arguments list to make the cause even more clear.

Replace static "Security Framework initializing" pr_info with specific
list of the resulting order of enabled LSMs.

For example, if the kernel is built with:

CONFIG_SECURITY_SELINUX=y
CONFIG_SECURITY_APPARMOR=y
CONFIG_SECURITY_LOADPIN=y
CONFIG_SECURITY_YAMA=y
CONFIG_SECURITY_SAFESETID=y
CONFIG_SECURITY_LOCKDOWN_LSM=y
CONFIG_SECURITY_LANDLOCK=y
CONFIG_INTEGRITY=y
CONFIG_BPF_LSM=y
CONFIG_DEFAULT_SECURITY_APPARMOR=y
CONFIG_LSM="landlock,lockdown,yama,loadpin,safesetid,integrity,selinux,
            smack,tomoyo,apparmor,bpf"

Booting without options will show:

LSM: initializing lsm=lockdown,capability,landlock,yama,loadpin,
     safesetid,integrity,selinux,bpf
landlock: Up and running.
Yama: becoming mindful.
LoadPin: ready to pin (currently not enforcing)
SELinux:  Initializing.
LSM support for eBPF active

Boot with "lsm.debug" will show:

LSM: legacy security= *unspecified*
LSM: CONFIG_LSM=landlock,lockdown,yama,loadpin,safesetid,integrity,
                selinux,smack,tomoyo,apparmor,bpf
LSM: boot arg lsm= *unspecified*
LSM:   early started: lockdown (enabled)
LSM:   first ordered: capability (enabled)
LSM: builtin ordered: landlock (enabled)
LSM: builtin ignored: lockdown (not built into kernel)
LSM: builtin ordered: yama (enabled)
LSM: builtin ordered: loadpin (enabled)
LSM: builtin ordered: safesetid (enabled)
LSM: builtin ordered: integrity (enabled)
LSM: builtin ordered: selinux (enabled)
LSM: builtin ignored: smack (not built into kernel)
LSM: builtin ignored: tomoyo (not built into kernel)
LSM: builtin ordered: apparmor (enabled)
LSM: builtin ordered: bpf (enabled)
LSM: exclusive chosen:   selinux
LSM: exclusive disabled: apparmor
LSM: initializing lsm=lockdown,capability,landlock,yama,loadpin,
                      safesetid,integrity,selinux,bpf
LSM: cred blob size       = 32
LSM: file blob size       = 16
LSM: inode blob size      = 72
LSM: ipc blob size        = 8
LSM: msg_msg blob size    = 4
LSM: superblock blob size = 80
LSM: task blob size       = 8
LSM: initializing capability
LSM: initializing landlock
landlock: Up and running.
LSM: initializing yama
Yama: becoming mindful.
LSM: initializing loadpin
LoadPin: ready to pin (currently not enforcing)
LSM: initializing safesetid
LSM: initializing integrity
LSM: initializing selinux
SELinux:  Initializing.
LSM: initializing bpf
LSM support for eBPF active

And some examples of how the lsm.debug ordering report changes...

With "lsm.debug security=selinux":

LSM: legacy security=selinux
LSM: CONFIG_LSM=landlock,lockdown,yama,loadpin,safesetid,integrity,
                selinux,smack,tomoyo,apparmor,bpf
LSM: boot arg lsm= *unspecified*
LSM:   early started: lockdown (enabled)
LSM:   first ordered: capability (enabled)
LSM: security=selinux disabled: apparmor (only one legacy major LSM)
LSM: builtin ordered: landlock (enabled)
LSM: builtin ignored: lockdown (not built into kernel)
LSM: builtin ordered: yama (enabled)
LSM: builtin ordered: loadpin (enabled)
LSM: builtin ordered: safesetid (enabled)
LSM: builtin ordered: integrity (enabled)
LSM: builtin ordered: selinux (enabled)
LSM: builtin ignored: smack (not built into kernel)
LSM: builtin ignored: tomoyo (not built into kernel)
LSM: builtin ordered: apparmor (disabled)
LSM: builtin ordered: bpf (enabled)
LSM: exclusive chosen:   selinux
LSM: initializing lsm=lockdown,capability,landlock,yama,loadpin,
		      safesetid,integrity,selinux,bpf

With "lsm.debug lsm=integrity,selinux,loadpin,crabability,bpf,
                    loadpin,loadpin":

LSM: legacy security= *unspecified*
LSM: CONFIG_LSM=landlock,lockdown,yama,loadpin,safesetid,integrity,
                selinux,smack,tomoyo,apparmor,bpf
LSM: boot arg lsm=integrity,selinux,loadpin,capability,bpf,loadpin,
		  loadpin
LSM:   early started: lockdown (enabled)
LSM:   first ordered: capability (enabled)
LSM: cmdline ordered: integrity (enabled)
LSM: cmdline ordered: selinux (enabled)
LSM: cmdline ordered: loadpin (enabled)
LSM: cmdline ignored: crabability (not built into kernel)
LSM: cmdline ordered: bpf (enabled)
LSM: cmdline skipped: apparmor (not in requested order)
LSM: cmdline skipped: yama (not in requested order)
LSM: cmdline skipped: safesetid (not in requested order)
LSM: cmdline skipped: landlock (not in requested order)
LSM: exclusive chosen:   selinux
LSM: initializing lsm=lockdown,capability,integrity,selinux,loadpin,bpf

Cc: Paul Moore <paul@paul-moore.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-security-module@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Mickaël Salaün <mic@digikod.net>
[PM: line wrapped commit description]
Signed-off-by: Paul Moore <paul@paul-moore.com>

diff --git a/security/security.c b/security/security.c
index f27c885ee98db1315698f7eb9df928d6c79d8472..d713d84d82d6462e3ed8a0ab9df7cc98ff85fb67 100644 (file)
--- a/security/security.c
+++ b/security/security.c
@@ -161,8 +161,8 @@ static void __init append_ordered_lsm(struct lsm_info *lsm, const char *from)
                lsm->enabled = &lsm_enabled_true;
        ordered_lsms[last_lsm++] = lsm;
 
-       init_debug("%s ordering: %s (%sabled)\n", from, lsm->name,
-                  is_enabled(lsm) ? "en" : "dis");
+       init_debug("%s ordered: %s (%s)\n", from, lsm->name,
+                  is_enabled(lsm) ? "enabled" : "disabled");
 }
 
 /* Is an LSM allowed to be initialized? */
@@ -224,7 +224,7 @@ static void __init prepare_lsm(struct lsm_info *lsm)
        if (enabled) {
                if ((lsm->flags & LSM_FLAG_EXCLUSIVE) && !exclusive) {
                        exclusive = lsm;
-                       init_debug("exclusive chosen: %s\n", lsm->name);
+                       init_debug("exclusive chosen:   %s\n", lsm->name);
                }
 
                lsm_set_blob_sizes(lsm->blobs);
@@ -252,7 +252,7 @@ static void __init ordered_lsm_parse(const char *order, const char *origin)
        /* LSM_ORDER_FIRST is always first. */
        for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) {
                if (lsm->order == LSM_ORDER_FIRST)
-                       append_ordered_lsm(lsm, "first");
+                       append_ordered_lsm(lsm, "  first");
        }
 
        /* Process "security=", if given. */
@@ -270,7 +270,7 @@ static void __init ordered_lsm_parse(const char *order, const char *origin)
                        if ((major->flags & LSM_FLAG_LEGACY_MAJOR) &&
                            strcmp(major->name, chosen_major_lsm) != 0) {
                                set_enabled(major, false);
-                               init_debug("security=%s disabled: %s\n",
+                               init_debug("security=%s disabled: %s (only one legacy major LSM)\n",
                                           chosen_major_lsm, major->name);
                        }
                }
@@ -291,7 +291,8 @@ static void __init ordered_lsm_parse(const char *order, const char *origin)
                }
 
                if (!found)
-                       init_debug("%s ignored: %s\n", origin, name);
+                       init_debug("%s ignored: %s (not built into kernel)\n",
+                                  origin, name);
        }
 
        /* Process "security=", if given. */
@@ -309,7 +310,8 @@ static void __init ordered_lsm_parse(const char *order, const char *origin)
                if (exists_ordered_lsm(lsm))
                        continue;
                set_enabled(lsm, false);
-               init_debug("%s disabled: %s\n", origin, lsm->name);
+               init_debug("%s skipped: %s (not in requested order)\n",
+                          origin, lsm->name);
        }
 
        kfree(sep);
@@ -320,6 +322,24 @@ static void __init lsm_early_task(struct task_struct *task);
 
 static int lsm_append(const char *new, char **result);
 
+static void __init report_lsm_order(void)
+{
+       struct lsm_info **lsm, *early;
+       int first = 0;
+
+       pr_info("initializing lsm=");
+
+       /* Report each enabled LSM name, comma separated. */
+       for (early = __start_early_lsm_info; early < __end_early_lsm_info; early++)
+               if (is_enabled(early))
+                       pr_cont("%s%s", first++ == 0 ? "" : ",", early->name);
+       for (lsm = ordered_lsms; *lsm; lsm++)
+               if (is_enabled(*lsm))
+                       pr_cont("%s%s", first++ == 0 ? "" : ",", (*lsm)->name);
+
+       pr_cont("\n");
+}
+
 static void __init ordered_lsm_init(void)
 {
        struct lsm_info **lsm;
@@ -329,7 +349,8 @@ static void __init ordered_lsm_init(void)
 
        if (chosen_lsm_order) {
                if (chosen_major_lsm) {
-                       pr_info("security= is ignored because it is superseded by lsm=\n");
+                       pr_warn("security=%s is ignored because it is superseded by lsm=%s\n",
+                               chosen_major_lsm, chosen_lsm_order);
                        chosen_major_lsm = NULL;
                }
                ordered_lsm_parse(chosen_lsm_order, "cmdline");
@@ -339,6 +360,8 @@ static void __init ordered_lsm_init(void)
        for (lsm = ordered_lsms; *lsm; lsm++)
                prepare_lsm(*lsm);
 
+       report_lsm_order();
+
        init_debug("cred blob size       = %d\n", blob_sizes.lbs_cred);
        init_debug("file blob size       = %d\n", blob_sizes.lbs_file);
        init_debug("inode blob size      = %d\n", blob_sizes.lbs_inode);
@@ -395,13 +418,17 @@ int __init security_init(void)
 {
        struct lsm_info *lsm;
 
-       pr_info("Security Framework initializing\n");
+       init_debug("legacy security=%s\n", chosen_major_lsm ?: " *unspecified*");
+       init_debug("  CONFIG_LSM=%s\n", builtin_lsm_order);
+       init_debug("boot arg lsm=%s\n", chosen_lsm_order ?: " *unspecified*");
 
        /*
         * Append the names of the early LSM modules now that kmalloc() is
         * available
         */
        for (lsm = __start_early_lsm_info; lsm < __end_early_lsm_info; lsm++) {
+               init_debug("  early started: %s (%s)\n", lsm->name,
+                          is_enabled(lsm) ? "enabled" : "disabled");
                if (lsm->enabled)
                        lsm_append(lsm->name, &lsm_names);
        }