path: root/Add-digest-list-plugin.patch

From e49074a4e4bd0699d2c4a5bb3a0dc5ca45e19e12 Mon Sep 17 00:00:00 2001
From: Roberto Sassu <roberto.sassu@huawei.com>
Date: Wed, 26 Feb 2020 15:54:24 +0100
Subject: [PATCH 2/3] Add digest list plugin

---
 macros.in             |   1 +
 plugins/Makefile.am   |   4 +
 plugins/digest_list.c | 498 ++++++++++++++++++++++++++++++++++++++++++
 rpmio/digest.h        |   1 +
 rpmio/rpmpgp.c        |   3 +
 5 files changed, 507 insertions(+)
 create mode 100644 plugins/digest_list.c

diff --git a/macros.in b/macros.in
index 402749362..8619c1323 100644
--- a/macros.in
+++ b/macros.in
@@ -1184,6 +1184,7 @@ package or when debugging this package.\
 %__transaction_prioreset	%{__plugindir}/prioreset.so
 %__transaction_audit		%{__plugindir}/audit.so
 %__transaction_dbus_announce	%{__plugindir}/dbus_announce.so
+%__transaction_digest_list	%{__plugindir}/digest_list.so
 
 #------------------------------------------------------------------------------
 # Macros for further automated spec %setup and patch application
diff --git a/plugins/Makefile.am b/plugins/Makefile.am
index d4ef039ed..07aa3585b 100644
--- a/plugins/Makefile.am
+++ b/plugins/Makefile.am
@@ -48,3 +48,7 @@ audit_la_sources = audit.c
 audit_la_LIBADD = $(top_builddir)/lib/librpm.la $(top_builddir)/rpmio/librpmio.la @WITH_AUDIT_LIB@
 plugins_LTLIBRARIES += audit.la
 endif
+
+digest_list_la_sources = digest_list.c
+digest_list_la_LIBADD = $(top_builddir)/lib/librpm.la $(top_builddir)/rpmio/librpmio.la
+plugins_LTLIBRARIES += digest_list.la
diff --git a/plugins/digest_list.c b/plugins/digest_list.c
new file mode 100644
index 000000000..beb397309
--- /dev/null
+++ b/plugins/digest_list.c
@@ -0,0 +1,499 @@
+#include "system.h"
+#include "errno.h"
+
+#include <fcntl.h>
+#include <rpm/rpmlog.h>
+#include <rpm/rpmts.h>
+#include <rpm/header.h>
+#include <rpmio/digest.h>
+#include <rpmio/rpmpgp.h>
+#include <rpm/rpmfileutil.h>
+#include "lib/rpmplugin.h"
+#include <netinet/in.h>
+#include <sys/stat.h>
+#include <openssl/sha.h>
+#include <sys/xattr.h>
+#include <linux/xattr.h>
+#include <asm/byteorder.h>
+#include <sys/wait.h>
+
+#include "debug.h"
+
+#define IMA_DIR "/sys/kernel/security/ima"
+#define DIGEST_LIST_DATA_PATH IMA_DIR "/digest_list_data"
+#define DIGEST_LIST_DATA_DEL_PATH IMA_DIR "/digest_list_data_del"
+#define DIGEST_LIST_COUNT IMA_DIR "/digests_count"
+#define DIGEST_LIST_DEFAULT_PATH "/etc/ima/digest_lists"
+#define RPM_PARSER "/usr/libexec/rpm_parser"
+
+#define DIGEST_LIST_OP_ADD 0
+#define DIGEST_LIST_OP_DEL 1
+
+enum hash_algo {
+	HASH_ALGO_MD4,
+	HASH_ALGO_MD5,
+	HASH_ALGO_SHA1,
+	HASH_ALGO_RIPE_MD_160,
+	HASH_ALGO_SHA256,
+	HASH_ALGO_SHA384,
+	HASH_ALGO_SHA512,
+	HASH_ALGO_SHA224,
+	HASH_ALGO_RIPE_MD_128,
+	HASH_ALGO_RIPE_MD_256,
+	HASH_ALGO_RIPE_MD_320,
+	HASH_ALGO_WP_256,
+	HASH_ALGO_WP_384,
+	HASH_ALGO_WP_512,
+	HASH_ALGO_TGR_128,
+	HASH_ALGO_TGR_160,
+	HASH_ALGO_TGR_192,
+	HASH_ALGO_SM3_256,
+	HASH_ALGO__LAST
+};
+
+#define PGPHASHALGO__LAST PGPHASHALGO_SHA224 + 1
+enum hash_algo pgp_algo_mapping[PGPHASHALGO__LAST] = {
+	[PGPHASHALGO_MD5] = HASH_ALGO_MD5,
+	[PGPHASHALGO_SHA1] = HASH_ALGO_SHA1,
+	[PGPHASHALGO_SHA224] = HASH_ALGO_SHA224,
+	[PGPHASHALGO_SHA256] = HASH_ALGO_SHA256,
+	[PGPHASHALGO_SHA384] = HASH_ALGO_SHA384,
+	[PGPHASHALGO_SHA512] = HASH_ALGO_SHA512,
+};
+
+/* from integrity.h */
+enum evm_ima_xattr_type {
+	IMA_XATTR_DIGEST = 0x01,
+	EVM_XATTR_HMAC,
+	EVM_IMA_XATTR_DIGSIG,
+	IMA_XATTR_DIGEST_NG,
+	EVM_XATTR_PORTABLE_DIGSIG,
+	EVM_IMA_XATTR_DIGEST_LIST,
+	IMA_XATTR_LAST
+};
+
+struct evm_ima_xattr_data {
+	uint8_t type;
+	uint8_t digest[SHA512_DIGEST_LENGTH + 1];
+} __attribute__((packed));
+
+struct signature_v2_hdr {
+	uint8_t type;		/* xattr type */
+	uint8_t version;	/* signature format version */
+	uint8_t hash_algo;	/* Digest algorithm [enum hash_algo] */
+	__be32 keyid;		/* IMA key identifier - not X509/PGP specific */
+	__be16 sig_size;	/* signature size */
+	uint8_t sig[0];		/* signature payload */
+} __attribute__((packed));
+
+static int upload_digest_list(char *path, int type, int digest_list_signed)
+{
+	size_t size;
+	char buf[21];
+	const char *ima_path = DIGEST_LIST_DATA_PATH;
+	struct stat st;
+	pid_t pid;
+	int ret = 0, fd;
+
+	if (type == TR_REMOVED)
+		ima_path = DIGEST_LIST_DATA_DEL_PATH;
+
+	if (stat(ima_path, &st) == -1)
+		return 0;
+
+	/* First determine if kernel interface can accept new digest lists */
+	fd = open(DIGEST_LIST_COUNT, O_RDONLY);
+	if (fd < 0) {
+		rpmlog(RPMLOG_ERR, "digest_list: could not open IMA interface "
+		       "'%s': %s\n", DIGEST_LIST_COUNT, strerror(errno));
+		return -EACCES;
+	}
+
+	ret = read(fd, buf, sizeof(buf));
+	close(fd);
+
+	if (ret <= 0) {
+		rpmlog(RPMLOG_ERR, "digest_list: could not read from IMA "
+		       "interface '%s': %s\n", DIGEST_LIST_COUNT,
+		       strerror(errno));
+		return -EACCES;
+	}
+
+	/* Last character is newline */
+	buf[ret - 1] = '\0';
+
+	rpmlog(RPMLOG_DEBUG, "digest_list: digests count %s\n", buf);
+
+	if (*buf == '0') {
+		rpmlog(RPMLOG_DEBUG, "digest_list: not uploading '%s' to IMA "
+		       "interface '%s'\n", path, ima_path);
+		return RPMRC_OK;
+	}
+
+	/* If the digest list is not signed, execute the RPM parser */
+	if (!digest_list_signed) {
+		if ((pid = fork()) == 0) {
+			execlp(RPM_PARSER, RPM_PARSER, (type == TR_ADDED) ?
+			       "add" : "del", path, NULL);
+			_exit(EXIT_FAILURE);
+		}
+
+		waitpid(pid, &ret, 0);
+		if (ret != 0)
+			rpmlog(RPMLOG_ERR, "digest_list: %s returned %d\n",
+			       RPM_PARSER, ret);
+		return 0;
+	}
+
+	fd = open(ima_path, O_WRONLY);
+	if (fd < 0) {
+		rpmlog(RPMLOG_ERR, "digest_list: could not open IMA interface "
+		       "'%s': %s\n", ima_path, strerror(errno));
+		return -EACCES;
+	}
+
+	/* Write the path of the digest list to securityfs */
+	size = write(fd, path, strlen(path));
+	if (size != strlen(path)) {
+		rpmlog(RPMLOG_ERR, "digest_list: could not write '%s' to IMA "
+		       "interface '%s': %s\n", path, ima_path, strerror(errno));
+		ret = -EIO;
+		goto out;
+	}
+
+	rpmlog(RPMLOG_DEBUG, "digest_list: written '%s' to '%s'\n", path,
+	       ima_path);
+out:
+	close(fd);
+	return ret;
+}
+
+static int write_rpm_digest_list(rpmte te, char *path)
+{
+	FD_t fd;
+	ssize_t written;
+	Header rpm = rpmteHeader(te);
+	rpmtd immutable;
+	int ret = 0;
+
+	immutable = rpmtdNew();
+	headerGet(rpm, RPMTAG_HEADERIMMUTABLE, immutable, 0);
+
+	fd = Fopen(path, "w.ufdio");
+	if (fd == NULL || Ferror(fd)) {
+		ret = -EACCES;
+		goto out;
+	}
+
+	written = Fwrite(rpm_header_magic, sizeof(uint8_t),
+			 sizeof(rpm_header_magic), fd);
+
+	if (written != sizeof(rpm_header_magic)) {
+		ret = -EIO;
+		goto out;
+	}
+
+	written = Fwrite(immutable->data, sizeof(uint8_t),
+			 immutable->count, fd);
+	if (written != immutable->count || Ferror(fd))
+		ret = -EIO;
+out:
+	Fclose(fd);
+	rpmtdFree(immutable);
+	return ret;
+}
+
+static int write_rpm_digest_list_ima_xattr(rpmte te, char *path)
+{
+	rpmtd signature;
+	ssize_t written;
+	uint8_t sig[2048] = { 0 };
+	pgpDigParams sigp = NULL;
+	struct signature_v2_hdr *sig_hdr = (struct signature_v2_hdr *)sig;
+	Header rpm = rpmteHeader(te);
+	FD_t fd;
+	int ret = 0, sig_size, sig_size_rounded;
+
+	signature = rpmtdNew();
+	headerGet(rpm, RPMTAG_RSAHEADER, signature, 0);
+	ret = pgpPrtParams(signature->data, signature->count,
+			   PGPTAG_SIGNATURE, &sigp);
+
+	if (ret) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	fd = Fopen(path, "a.ufdio");
+	if (fd == NULL || Ferror(fd)) {
+		ret = -EACCES;
+		goto out;
+	}
+
+	written = Fwrite(sigp->hash, sizeof(uint8_t),
+			 sigp->hashlen, fd);
+	if (written != sigp->hashlen || Ferror(fd)) {
+		ret = -EIO;
+		goto out;
+	}
+
+	if (sigp->version == 4) {
+		/* V4 trailer is six octets long (rfc4880) */
+		uint8_t trailer[6];
+		uint32_t nb = sigp->hashlen;
+		nb = htonl(nb);
+		trailer[0] = sigp->version;
+		trailer[1] = 0xff;
+		memcpy(trailer+2, &nb, 4);
+
+		written = Fwrite(trailer, sizeof(uint8_t), sizeof(trailer), fd);
+		if (written != sizeof(trailer) || Ferror(fd)) {
+			ret = -EIO;
+			goto out;
+		}
+	}
+
+	Fclose(fd);
+
+	sig_hdr->type = EVM_IMA_XATTR_DIGSIG;
+	sig_hdr->version = 2;
+	sig_hdr->hash_algo = pgp_algo_mapping[sigp->hash_algo];
+	memcpy((void *)&sig_hdr->keyid, sigp->signid + sizeof(uint32_t),
+	       sizeof(uint32_t));
+
+	sig_size = (pgpMpiBits(sigp->data) + 7) >> 3;
+	if (sizeof(sig_hdr) + sig_size > sizeof(sig)) {
+		rpmlog(RPMLOG_ERR,
+		       "digest_list: signature in %s too big\n", path);
+		ret = -E2BIG;
+		goto out;
+	}
+
+	sig_size_rounded = ((sig_size + 7) >> 3) * 8;
+	sig_hdr->sig_size = __cpu_to_be16(sig_size_rounded);
+
+	memcpy(sig_hdr->sig + sig_size_rounded - sig_size,
+	       (uint8_t *)sigp->data + 2, sig_size);
+
+	ret = lsetxattr(path, XATTR_NAME_IMA,
+			sig, sizeof(*sig_hdr) + sig_size_rounded, 0);
+	if (ret < 0)
+		rpmlog(RPMLOG_ERR, "digest_list: could not apply security.ima "
+		       "on '%s': %s\n", path, strerror(errno));
+	else
+		rpmlog(RPMLOG_DEBUG, "digest_list: security.ima successfully "
+		       "applied on '%s'\n", path);
+out:
+	pgpDigParamsFree(sigp);
+	rpmtdFree(signature);
+	return ret;
+}
+
+static int write_digest_list_ima_xattr(rpmte te, char *path, char *path_sig)
+{
+	rpmtd signature;
+	uint8_t sig[2048] = { 0 };
+	pgpDigParams sigp = NULL;
+	struct signature_v2_hdr *sig_hdr = (struct signature_v2_hdr *)sig;
+	Header rpm = rpmteHeader(te);
+	FD_t fd;
+	struct stat st;
+	int ret = 0, sig_size;
+
+	signature = rpmtdNew();
+	headerGet(rpm, RPMTAG_RSAHEADER, signature, 0);
+	ret = pgpPrtParams(signature->data, signature->count,
+			   PGPTAG_SIGNATURE, &sigp);
+
+	if (ret) {
+		ret = -ENOENT;
+		goto out;
+	}
+
+	sig_hdr->type = EVM_IMA_XATTR_DIGSIG;
+	sig_hdr->version = 2;
+	sig_hdr->hash_algo = HASH_ALGO_SHA256;
+	memcpy((void *)&sig_hdr->keyid, sigp->signid + sizeof(uint32_t),
+	       sizeof(uint32_t));
+
+	if (stat(path_sig, &st) == -1) {
+		ret = -EACCES;
+		goto out;
+	}
+
+	if (sizeof(sig_hdr) + st.st_size > sizeof(sig)) {
+		rpmlog(RPMLOG_ERR, "digest_list: signature in %s too big\n",
+		       path);
+		ret = -E2BIG;
+		goto out;
+	}
+
+	fd = Fopen(path_sig, "r.ufdio");
+	if (fd < 0) {
+		rpmlog(RPMLOG_ERR, "digest_list: could not open '%s': %s\n",
+		       path_sig, strerror(errno));
+		ret = -EACCES;
+		goto out;
+	}
+
+	sig_size = Fread(sig_hdr->sig, sizeof(uint8_t), st.st_size, fd);
+	if (sig_size != st.st_size || Ferror(fd)) {
+		rpmlog(RPMLOG_ERR, "digest_list: could not read '%s': %s\n",
+		       path_sig, strerror(errno));
+		Fclose(fd);
+		ret = -EIO;
+		goto out;
+	}
+
+	sig_hdr->sig_size = __cpu_to_be16(sig_size);
+
+	rpmlog(RPMLOG_DEBUG,
+	       "digest_list: read signature of %d bytes from '%s'\n",
+	       sig_size, path_sig);
+
+	ret = lsetxattr(path, XATTR_NAME_IMA,
+			sig, sizeof(*sig_hdr) + sig_size, 0);
+	if (ret < 0)
+		rpmlog(RPMLOG_ERR, "digest_list: could not apply security.ima "
+		       "on '%s': %s\n", path, strerror(errno));
+	else
+		rpmlog(RPMLOG_DEBUG, "digest_list: security.ima successfully "
+		       "applied on '%s'\n", path);
+out:
+	pgpDigParamsFree(sigp);
+	rpmtdFree(signature);
+	return ret;
+}
+
+static int process_digest_list(rpmte te, int parser)
+{
+	char *path = NULL, *path_sig = NULL;
+	int digest_list_signed = 0;
+	struct stat st;
+	ssize_t size;
+	rpmRC ret = RPMRC_OK;
+
+	path = malloc(PATH_MAX);
+	if (!path) {
+		ret = RPMRC_FAIL;
+		goto out;
+	}
+
+	path_sig = malloc(PATH_MAX);
+	if (!path_sig) {
+		ret = RPMRC_FAIL;
+		goto out;
+	}
+
+	if (parser)
+		snprintf(path_sig, PATH_MAX,
+			 "%s.sig/0-parser_list-compact-libexec.sig",
+			 DIGEST_LIST_DEFAULT_PATH);
+	else
+		snprintf(path_sig, PATH_MAX,
+			"%s.sig/0-metadata_list-compact-%s-%s-%s.%s.sig",
+			 DIGEST_LIST_DEFAULT_PATH, rpmteN(te), rpmteV(te),
+			 rpmteR(te), rpmteA(te));
+
+	if (!stat(path_sig, &st))
+		digest_list_signed = 1;
+
+	if (parser && !digest_list_signed)
+		goto out;
+
+	if (parser)
+		snprintf(path, PATH_MAX, "%s/0-parser_list-compact-libexec",
+			 DIGEST_LIST_DEFAULT_PATH);
+	else
+		snprintf(path, PATH_MAX,
+			 "%s/0-metadata_list-compact-%s-%s-%s.%s",
+			 DIGEST_LIST_DEFAULT_PATH, rpmteN(te), rpmteV(te),
+			 rpmteR(te), rpmteA(te));
+
+	if (stat(path, &st) == -1)
+		goto out;
+
+	if (!parser && !digest_list_signed)
+		snprintf(path, PATH_MAX, "%s/0-metadata_list-rpm-%s-%s-%s.%s",
+			 DIGEST_LIST_DEFAULT_PATH, rpmteN(te), rpmteV(te),
+			 rpmteR(te), rpmteA(te));
+
+	size = lgetxattr(path, XATTR_NAME_IMA, NULL, 0);
+
+	/* Don't upload again if digest list was already processed */
+	if ((rpmteType(te) == TR_ADDED && size > 0) ||
+	    (rpmteType(te) == TR_REMOVED && size < 0)) {
+		rpmlog(RPMLOG_DEBUG, "digest_list: '%s' already processed, "
+		       "nothing to do\n", path);
+		goto out;
+	}
+
+	if (rpmteType(te) == TR_ADDED) {
+		if (!digest_list_signed) {
+			/* Write RPM header to the disk */
+			ret = write_rpm_digest_list(te, path);
+			if (ret < 0) {
+				ret = RPMRC_FAIL;
+				goto out;
+			}
+
+			/* Write RPM header sig to security.ima */
+			ret = write_rpm_digest_list_ima_xattr(te, path);
+		} else {
+			ret = write_digest_list_ima_xattr(te, path, path_sig);
+		}
+
+		if (ret < 0) {
+			ret = RPMRC_FAIL;
+			goto out;
+		}
+	}
+
+	/* Upload digest list to securityfs */
+	upload_digest_list(path, rpmteType(te), digest_list_signed);
+
+	if (rpmteType(te) == TR_REMOVED) {
+		if (!digest_list_signed) {
+			unlink(path);
+			goto out;
+		}
+
+		ret = lremovexattr(path, XATTR_NAME_IMA);
+		if (ret < 0)
+			rpmlog(RPMLOG_ERR, "digest_list: cannot remove "
+			       "security.ima from '%s'\n", path);
+		else
+			rpmlog(RPMLOG_DEBUG, "digest_list: security.ima "
+			       "successfully removed from '%s'\n", path);
+	}
+out:
+	free(path);
+	free(path_sig);
+	return ret;
+}
+
+static rpmRC digest_list_psm_pre(rpmPlugin plugin, rpmte te)
+{
+	process_digest_list(te, 0);
+	if (!strcmp(rpmteN(te), "digest-list-tools"))
+		process_digest_list(te, 1);
+
+	return RPMRC_OK;
+}
+
+static rpmRC digest_list_psm_post(rpmPlugin plugin, rpmte te, int res)
+{
+	if (res != RPMRC_OK)
+		return RPMRC_OK;
+
+	process_digest_list(te, 0);
+	if (!strcmp(rpmteN(te), "digest-list-tools"))
+		process_digest_list(te, 1);
+
+	return RPMRC_OK;
+}
+
+struct rpmPluginHooks_s digest_list_hooks = {
+	.psm_pre = digest_list_psm_pre,
+	.psm_post = digest_list_psm_post,
+};
diff --git a/rpmio/digest.h b/rpmio/digest.h
index 9e0cde3b9..01ca10d92 100644
--- a/rpmio/digest.h
+++ b/rpmio/digest.h
@@ -24,6 +24,7 @@ struct pgpDigAlg_s {
 struct pgpDigParams_s {
     char * userid;
     uint8_t * hash;
+    const uint8_t * data;
     uint8_t tag;
 
     uint8_t version;		/*!< version number. */
diff --git a/rpmio/rpmpgp.c b/rpmio/rpmpgp.c
index 46cd0f31a..3c6b18b53 100644
--- a/rpmio/rpmpgp.c
+++ b/rpmio/rpmpgp.c
@@ -600,6 +600,7 @@ static int pgpPrtSig(pgpTag tag, const uint8_t *h, size_t hlen,
 	}
 
 	p = ((uint8_t *)v) + sizeof(*v);
+	_digp->data = p;
 	rc = pgpPrtSigParams(tag, v->pubkey_algo, v->sigtype, p, h, hlen, _digp);
     }	break;
     case 4:
@@ -658,6 +659,7 @@ static int pgpPrtSig(pgpTag tag, const uint8_t *h, size_t hlen,
 	if (p > hend)
 	    return 1;
 
+	_digp->data = p;
 	rc = pgpPrtSigParams(tag, v->pubkey_algo, v->sigtype, p, h, hlen, _digp);
     }	break;
     default:
@@ -745,6 +747,7 @@ static int pgpPrtKey(pgpTag tag, const uint8_t *h, size_t hlen,
 	    }
 
 	    p = ((uint8_t *)v) + sizeof(*v);
+	    _digp->data = p;
 	    rc = pgpPrtPubkeyParams(v->pubkey_algo, p, h, hlen, _digp);
 	}
     }	break;
-- 
2.27.GIT