From 820dcc1db9f2130a21fdaf721217034376eb8e38 Mon Sep 17 00:00:00 2001
Message-Id: <820dcc1db9f2130a21fdaf721217034376eb8e38.1544785848.git.pmatilai@redhat.com>
From: Panu Matilainen <pmatilai@redhat.com>
Date: Fri, 30 Nov 2018 13:10:44 +0200
Subject: [PATCH] Add support for logging audit events for package installs as
 per OSPP v4.2

If enabled at build-time, log audit events for package install, update
and remove. The log includes the operation, package nevra, signature
check result, whether signatures are being enforced enforced and overall
success result. Package install/update/remove are logged as such,
obsoletion is logged as install + remove (whereas the erasure element
on updates is silent)

Loosely based on initial RHEL 7-8 implementations by Pavlina Moravcova
Varekova and Florian Festi (RhBug:1555326, RhBug:1607612)

(cherry picked from commit cfc9dde70fe65e91c83e03e9a9441e627b741489)
---
 configure.ac         |  21 +++++++++
 lib/Makefile.am      |   1 +
 lib/rpmte.c          |  11 +++++
 lib/rpmte_internal.h |   6 +++
 lib/transaction.c    | 104 +++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 143 insertions(+)

diff --git a/configure.ac b/configure.ac
index 34ea85f9f..ab8a368d3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -312,6 +312,27 @@ fi
 AC_SUBST(WITH_BEECRYPT_LIB)
 AC_SUBST(WITH_BEECRYPT_INCLUDE)
 
+
+#=================
+# Check for audit library.
+AC_ARG_WITH(audit,
+AS_HELP_STRING([--with-audit],[log results using Linux Audit]),
+with_audit=$withval,
+with_audit=auto)
+
+WITH_AUDIT_LIB=
+AS_IF([test "x$with_audit" != xno],[
+    AC_SEARCH_LIBS([audit_open],[audit],[
+    WITH_AUDIT_LIB="$ac_res"
+    AC_DEFINE(WITH_AUDIT, 1, [libaudit support])
+    ],
+       [if test "x$with_audit" != xauto; then
+		AC_MSG_ERROR([missing audit library])
+	fi
+    ])
+])
+AC_SUBST(WITH_AUDIT_LIB)
+
 #=================
 # Check for OpenSSL library.
 # We need evp.h from OpenSSL.
diff --git a/lib/Makefile.am b/lib/Makefile.am
index baf3238ee..c055962a3 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -51,6 +51,7 @@ librpm_la_LIBADD = \
 	@WITH_POPT_LIB@ \
 	@WITH_CAP_LIB@ \
 	@WITH_ACL_LIB@ \
+	@WITH_AUDIT_LIB@ \
 	@LIBINTL@
 
 if WITH_LUA
diff --git a/lib/rpmte.c b/lib/rpmte.c
index d980a37a4..bd5d53edc 100644
--- a/lib/rpmte.c
+++ b/lib/rpmte.c
@@ -69,6 +69,7 @@ struct rpmte_s {
     int nrelocs;		/*!< (TR_ADDED) No. of relocations. */
     uint8_t *badrelocs;		/*!< (TR_ADDED) Bad relocations (or NULL) */
     FD_t fd;			/*!< (TR_ADDED) Payload file descriptor. */
+    int verified;		/*!< (TR_ADDED) Verification status */
 
 #define RPMTE_HAVE_PRETRANS	(1 << 0)
 #define RPMTE_HAVE_POSTTRANS	(1 << 1)
@@ -753,6 +754,16 @@ rpmfs rpmteGetFileStates(rpmte te)
     return te->fs;
 }
 
+void rpmteSetVerified(rpmte te, int verified)
+{
+    te->verified = verified;
+}
+
+int rpmteGetVerified(rpmte te)
+{
+    return te->verified;
+}
+
 int rpmteProcess(rpmte te, pkgGoal goal, int num)
 {
     /* Only install/erase resets pkg file info */
diff --git a/lib/rpmte_internal.h b/lib/rpmte_internal.h
index a5a991ec5..2895925ce 100644
--- a/lib/rpmte_internal.h
+++ b/lib/rpmte_internal.h
@@ -86,6 +86,12 @@ int rpmteHaveTransScript(rpmte te, rpmTagVal tag);
 /* XXX should be internal too but build code needs for now... */
 rpmfs rpmteGetFileStates(rpmte te);
 
+RPM_GNUC_INTERNAL
+void rpmteSetVerified(rpmte te, int verified);
+
+RPM_GNUC_INTERNAL
+int rpmteGetVerified(rpmte te);
+
 /** \ingroup rpmte
  * Retrieve size in bytes of package header.
  * @param te		transaction element
diff --git a/lib/transaction.c b/lib/transaction.c
index 67b9db579..866e87fc2 100644
--- a/lib/transaction.c
+++ b/lib/transaction.c
@@ -7,6 +7,10 @@
 #include <inttypes.h>
 #include <libgen.h>
 
+#if WITH_AUDIT
+#include <libaudit.h>
+#endif
+
 #include <rpm/rpmlib.h>		/* rpmMachineScore, rpmReadPackageFile */
 #include <rpm/rpmmacro.h>	/* XXX for rpmExpand */
 #include <rpm/rpmlog.h>
@@ -1195,12 +1199,17 @@ static rpm_loff_t countPkgs(rpmts ts, rpmElementTypes types)
 
 struct vfydata_s {
     char *msg;
+    int signature;
     int vfylevel;
 };
 
 static int vfyCb(struct rpmsinfo_s *sinfo, void *cbdata)
 {
     struct vfydata_s *vd = cbdata;
+
+    if (sinfo->type == RPMSIG_SIGNATURE_TYPE && sinfo->rc == RPMRC_OK)
+	vd->signature = RPMRC_OK;
+
     switch (sinfo->rc) {
     case RPMRC_OK:
 	break;
@@ -1241,6 +1250,7 @@ static int verifyPackageFiles(rpmts ts, rpm_loff_t total)
 	struct rpmvs_s *vs = rpmvsCreate(vfylevel, vsflags, keyring);
 	struct vfydata_s vd = {
 	    .msg = NULL,
+	    .signature = RPMRC_NOTFOUND,
 	    .vfylevel = vfylevel,
 	};
 	rpmRC prc = RPMRC_FAIL;
@@ -1255,6 +1265,9 @@ static int verifyPackageFiles(rpmts ts, rpm_loff_t total)
 	if (prc == RPMRC_OK)
 	    prc = rpmvsVerify(vs, RPMSIG_VERIFIABLE_TYPE, vfyCb, &vd);
 
+	/* Record verify result, signatures only for now */
+	rpmteSetVerified(p, vd.signature == RPMRC_OK);
+
 	if (prc)
 	    rpmteAddProblem(p, RPMPROB_VERIFY, NULL, vd.msg, 0);
 
@@ -1619,6 +1632,95 @@ rpmRC runScript(rpmts ts, rpmte te, Header h, ARGV_const_t prefixes,
     return rc;
 }
 
+#if WITH_AUDIT
+struct teop {
+    rpmte te;
+    const char *op;
+};
+
+/*
+ * Figure out the actual operations:
+ * Install and remove are straightforward. Updates need to discovered 
+ * via their erasure element: locate the updating element, adjust it's
+ * op to update and silence the erasure part. Obsoletion is handled as
+ * as install + remove, which it technically is.
+ */
+static void getAuditOps(rpmts ts, struct teop *ops, int nelem)
+{
+    rpmtsi pi = rpmtsiInit(ts);
+    rpmte p;
+    int i = 0;
+    while ((p = rpmtsiNext(pi, 0)) != NULL) {
+	const char *op = NULL;
+	if (rpmteType(p) == TR_ADDED) {
+	    op = "install";
+	} else {
+	    op = "remove";
+	    rpmte d = rpmteDependsOn(p);
+	    /* Fixup op on updating elements, silence the cleanup stage */
+	    if (d != NULL && rstreq(rpmteN(d), rpmteN(p))) {
+		/* Linear lookup, but we're only dealing with a few thousand */
+		for (int x = 0; x < i; x++) {
+		    if (ops[x].te == d) {
+			ops[x].op = "update";
+			op = NULL;
+			break;
+		    }
+		}
+	    }
+	}
+	ops[i].te = p;
+	ops[i].op = op;
+	i++;
+    }
+    rpmtsiFree(pi);
+}
+
+/*
+ * If enabled, log audit events for the operations in this transaction.
+ * In the event values, 1 means true/success and 0 false/failure. Shockingly.
+ */
+static void rpmtsAudit(rpmts ts)
+{
+    int auditFd = audit_open();
+    if (auditFd < 0)
+	return;
+
+    int nelem = rpmtsNElements(ts);
+    struct teop *ops = xcalloc(nelem, sizeof(*ops));
+    char *dir = audit_encode_nv_string("root_dir", rpmtsRootDir(ts), 0);
+    int enforce = (rpmtsVfyLevel(ts) & RPMSIG_SIGNATURE_TYPE) != 0;
+
+    getAuditOps(ts, ops, nelem);
+
+    for (int i = 0; i < nelem; i++) {
+	const char *op = ops[i].op;
+	if (op) {
+	    rpmte p = ops[i].te;
+	    char *nevra = audit_encode_nv_string("sw", rpmteNEVRA(p), 0);
+	    char eventTxt[256];
+	    int verified = rpmteGetVerified(p);
+	    int result = (rpmteFailed(p) == 0);
+
+	    snprintf(eventTxt, sizeof(eventTxt),
+		    "op=%s %s sw_type=rpm key_enforce=%u gpg_res=%u %s",
+		    op, nevra, enforce, verified, dir);
+	    audit_log_user_comm_message(auditFd, AUDIT_SOFTWARE_UPDATE,
+				    eventTxt, NULL, NULL, NULL, NULL, result);
+	    free(nevra);
+	}
+    }
+
+    free(dir);
+    free(ops);
+    audit_close(auditFd);
+}
+#else
+static void rpmtsAudit(rpmts ts)
+{
+}
+#endif
+
 int rpmtsRun(rpmts ts, rpmps okProbs, rpmprobFilterFlags ignoreSet)
 {
     int rc = -1; /* assume failure */
@@ -1732,6 +1834,8 @@ exit:
 	rpmpluginsCallTsmPost(rpmtsPlugins(ts), ts, rc);
 
     /* Finish up... */
+    if (!(rpmtsFlags(ts) & (RPMTRANS_FLAG_TEST|RPMTRANS_FLAG_BUILD_PROBS)))
+	rpmtsAudit(ts);
     (void) umask(oldmask);
     (void) rpmtsFinish(ts);
     rpmpsFree(tsprobs);
-- 
2.19.2