[OE-Core][master][kirkstone][PATCH] rng-tools: backport patch to adjust jitterentropy library to timeout/fail on long delay

[Xiangyu Chen <xiangyu.chen@eng.windriver.com>]

Backport patch from upstream[1] to adjust jitter to timeout on init after 5 seconds in the event it takes
to long to gether jitter entropy.This also fix rng-tools take full cpu usage with whole cores on ARM platforms.

[1] https://github.com/nhorman/rng-tools/pull/171/commits/c29424f10a0dcbd18ac25607fa1c81c18a960e81

Signed-off-by: Xiangyu Chen <xiangyu.chen@eng.windriver.com>
---
 ...ropy-library-to-timeout-fail-on-long.patch | 144 ++++++++++++++++++
 .../rng-tools/rng-tools_6.15.bb               |   1 +
 2 files changed, 145 insertions(+)
 create mode 100644 meta/recipes-support/rng-tools/rng-tools/0001-Adjust-jitterentropy-library-to-timeout-fail-on-long.patch

diff --git a/meta/recipes-support/rng-tools/rng-tools/0001-Adjust-jitterentropy-library-to-timeout-fail-on-long.patch b/meta/recipes-support/rng-tools/rng-tools/0001-Adjust-jitterentropy-library-to-timeout-fail-on-long.patch
new file mode 100644
index 0000000000..d70c6587aa
--- /dev/null
+++ b/meta/recipes-support/rng-tools/rng-tools/0001-Adjust-jitterentropy-library-to-timeout-fail-on-long.patch
@@ -0,0 +1,144 @@
+From 3f1d6e53985e40cbe4c7380ce503ca2778d4cd9d Mon Sep 17 00:00:00 2001
+From: Neil Horman <nhorman@tuxdriver.com>
+Date: Mon, 16 May 2022 13:38:54 -0400
+Subject: [PATCH] Adjust jitterentropy library to timeout/fail on long delay
+
+When running rngd -l its possible, on platforms that have low jitter
+entropy to block for long periods of time.  Adjust jitter to timeout on
+init after 5 seconds in the event it takes to long to gether jitter
+entropy
+
+Also while we're at it, I might have a build solution for the presence
+of internal timers.  When jitterentropy is built without internal
+timers, jent_notime_init is defined publically, but when it is built
+with timers, its declared as a static symbol, preenting resolution, so
+we can test to see if the function exists.  If it does we _don't_ have
+notime support. The logic is a bit backwards, but i think it works
+
+Upstream-Status: Backport from
+[https://github.com/nhorman/rng-tools/pull/171/commits/c29424f10a0dcbd18ac25607fa1c81c18a960e81]
+
+Signed-off-by: Xiangyu Chen <xiangyu.chen@eng.windriver.com>
+---
+ configure.ac  |  6 ++---
+ rngd_jitter.c | 61 +++++++++++++++++++++++++++++++++++++++------------
+ 2 files changed, 50 insertions(+), 17 deletions(-)
+
+diff --git a/configure.ac b/configure.ac
+index 40008ca..2e12308 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -94,9 +94,9 @@ AS_IF(
+ 		AC_SEARCH_LIBS(jent_version,jitterentropy,
+ 				[AM_CONDITIONAL([JITTER], [true])
+ 				AC_DEFINE([HAVE_JITTER],1,[Enable JITTER])
+-				AC_CHECK_LIB(jitterentropy, jent_entropy_switch_notime_impl,
+-				[AC_DEFINE([HAVE_JITTER_NOTIME],1,[Enable JITTER_NOTIME])],
+-				[],-lpthread)],
++				AC_CHECK_LIB(jitterentropy, jent_notime_init,
++				[],
++				[AC_DEFINE([HAVE_JITTER_NOTIME],1, [Enable JITTER_NOTIME])],-lpthread)],
+ 				AC_MSG_NOTICE([No Jitterentropy library found]),-lpthread)
+ 	], [AC_MSG_NOTICE([Disabling JITTER entropy source])]
+ )
+diff --git a/rngd_jitter.c b/rngd_jitter.c
+index d1b17ba..3647b7f 100644
+--- a/rngd_jitter.c
++++ b/rngd_jitter.c
+@@ -400,6 +400,8 @@ int init_jitter_entropy_source(struct rng *ent_src)
+ 	int entflags = 0;
+ 	int ret;
+ 	int core_id = 0;
++	struct timespec base, now;
++	int rc;
+ 
+ 	signal(SIGUSR1, jitter_thread_exit_signal);
+ 
+@@ -508,6 +510,10 @@ int init_jitter_entropy_source(struct rng *ent_src)
+ 	CPU_FREE(cpus);
+ 	cpus = NULL;
+ 
++	flags = fcntl(pipefds[0], F_GETFL, 0);
++	flags |= O_NONBLOCK;
++	fcntl(pipefds[0], F_SETFL, flags);
++
+ 	if (ent_src->rng_options[JITTER_OPT_USE_AES].int_val) {
+ 		/*
+ 		 * Temporarily disable aes so we don't try to use it during init
+@@ -516,32 +522,59 @@ int init_jitter_entropy_source(struct rng *ent_src)
+ 		message_entsrc(ent_src,LOG_CONS|LOG_INFO, "Initializing AES buffer\n");
+ 		aes_buf = malloc(tdata[0].buf_sz);
+ 		ent_src->rng_options[JITTER_OPT_USE_AES].int_val = 0;
+-		if (xread_jitter(key, AES_BLOCK, ent_src)) {
+-			message_entsrc(ent_src,LOG_CONS|LOG_INFO, "Unable to obtain AES key, disabling AES in JITTER source\n");
+-		} else if (xread_jitter(iv_buf, CHUNK_SIZE, ent_src)) {
+-			message_entsrc(ent_src,LOG_CONS|LOG_INFO, "Unable to obtain iv_buffer, disabling AES in JITTER source\n");
++		clock_gettime(CLOCK_REALTIME, &base);
++		do {
++			rc = xread_jitter(key, AES_BLOCK, ent_src);
++			clock_gettime(CLOCK_REALTIME, &now);
++		} while (rc && ((now.tv_sec - base.tv_sec) < 5));
++
++		if (rc) {
++			message_entsrc(ent_src,LOG_CONS|LOG_INFO, "Unable to obtain AES key, disabling JITTER source\n");
++			close_jitter_entropy_source(ent_src);
++			return 1;
++		}
++		do {
++			rc = xread_jitter(iv_buf, CHUNK_SIZE, ent_src);
++			clock_gettime(CLOCK_REALTIME, &now);
++		} while (rc && ((now.tv_sec - base.tv_sec) < 5));
++
++		if (rc) {
++			message_entsrc(ent_src,LOG_CONS|LOG_INFO, "Unable to obtain iv_buffer, disabling JITTER source\n");
++			close_jitter_entropy_source(ent_src);
++			return 1;
+ 		} else {
+ 			/* re-enable AES */
+ 			ent_src->rng_options[JITTER_OPT_USE_AES].int_val = 1;
+ 			ossl_ctx = ossl_aes_init(key, iv_buf);
+ 		}
+-		xread_jitter(aes_buf, tdata[0].buf_sz, ent_src);
++
++		do {
++			rc = xread_jitter(aes_buf, tdata[0].buf_sz, ent_src);
++			clock_gettime(CLOCK_REALTIME, &now);
++		} while (rc && ((now.tv_sec - base.tv_sec) < 5));
++		if (rc) {
++			message_entsrc(ent_src,LOG_CONS|LOG_INFO, "Unable to obtain aes buffer, disabling JITTER source\n");
++			close_jitter_entropy_source(ent_src);
++			return 1;
++		}
++
+ 	} else {
+ 		/*
+-		 * Make sure that an entropy gathering thread has generated
+-		 * at least some entropy before setting O_NONBLOCK and finishing
+-		 * the entropy source initialization.
+-		 *
+ 		 * This avoids "Entropy Generation is slow" log spamming that
+ 		 * would otherwise happen until jent_read_entropy() has run
+ 		 * for the first time.
+ 		 */
+-		xread_jitter(&i, 1, ent_src);
+-	}
++		do {
++			rc = xread_jitter(&i, 1, ent_src);
++			clock_gettime(CLOCK_REALTIME, &now);
++		} while (rc && ((now.tv_sec - base.tv_sec) < 5));
++		if (rc) {
++			message_entsrc(ent_src,LOG_CONS|LOG_INFO, "Unable to prime jitter source, disabling JITTER source\n");
++			close_jitter_entropy_source(ent_src);
++			return 1;
++		}
+ 
+-	flags = fcntl(pipefds[0], F_GETFL, 0);
+-	flags |= O_NONBLOCK;
+-	fcntl(pipefds[0], F_SETFL, flags);
++	}
+ 
+ 	message_entsrc(ent_src,LOG_DAEMON|LOG_INFO, "Enabling JITTER rng support\n");
+ 	return 0;
+-- 
+2.34.1
+
diff --git a/meta/recipes-support/rng-tools/rng-tools_6.15.bb b/meta/recipes-support/rng-tools/rng-tools_6.15.bb
index efc08b5e0a..c6284f0006 100644
--- a/meta/recipes-support/rng-tools/rng-tools_6.15.bb
+++ b/meta/recipes-support/rng-tools/rng-tools_6.15.bb
@@ -12,6 +12,7 @@ SRC_URI = "git://github.com/nhorman/rng-tools.git;branch=master;protocol=https \
            file://init \
            file://default \
            file://rng-tools.service \
+           file://0001-Adjust-jitterentropy-library-to-timeout-fail-on-long.patch \
            "
 SRCREV = "381f69828b782afda574f259c1b7549f48f9bb77"
 
-- 
2.34.1