Always show the OpenSSL error queue after failure.

Any failed OpenSSL function may have pushed errors onto the error queue.
Thus, after any failed OpenSSL function it needs to be cleared otherwise
it may leave errors on the queue for future operations.

Signed-off-by: Adam Langley <agl@chromium.org>
(EB: made error_msg_openssl() call do_error_msg())
Signed-off-by: Eric Biggers <ebiggers@google.com>

3 files changed, 27 insertions, 25 deletions

diff --git a/sign.c b/sign.c
index 13a3f3d..d7bf078 100644
--- a/sign.c
+++ b/sign.c
@@ -20,8 +20,15 @@
 #include "fsveritysetup.h"
 #include "hash_algs.h"
 
-static void display_openssl_errors(void)
+static void __printf(1, 2) __cold
+error_msg_openssl(const char *format, ...)
 {
+	va_list va;
+
+	va_start(va, format);
+	do_error_msg(format, va, 0);
+	va_end(va);
+
 	if (ERR_peek_error() == 0)
 		return;
 
@@ -41,7 +48,7 @@ static BIO *new_mem_buf(const void *buf, size_t size)
 	 */
 	bio = BIO_new_mem_buf((void *)buf, size);
 	if (!bio)
-		error_msg("out of memory");
+		error_msg_openssl("out of memory");
 	return bio;
 }
 
@@ -53,16 +60,15 @@ static EVP_PKEY *read_private_key(const char *keyfile)
 
 	bio = BIO_new_file(keyfile, "r");
 	if (!bio) {
-		error_msg_errno("can't open '%s' for reading", keyfile);
+		error_msg_openssl("can't open '%s' for reading", keyfile);
 		return NULL;
 	}
 
 	pkey = PEM_read_bio_PrivateKey(bio, NULL, NULL, NULL);
 	if (!pkey) {
-		error_msg("Failed to parse private key file '%s'.\n"
-			  "       Note: it must be in PEM PKCS#8 format.",
-			  keyfile);
-		display_openssl_errors();
+		error_msg_openssl("Failed to parse private key file '%s'.\n"
+				  "       Note: it must be in PEM PKCS#8 format.",
+				  keyfile);
 	}
 	BIO_free(bio);
 	return pkey;
@@ -76,15 +82,14 @@ static X509 *read_certificate(const char *certfile)
 
 	bio = BIO_new_file(certfile, "r");
 	if (!bio) {
-		error_msg_errno("can't open '%s' for reading", certfile);
+		error_msg_openssl("can't open '%s' for reading", certfile);
 		return NULL;
 	}
 	cert = PEM_read_bio_X509(bio, NULL, NULL, NULL);
 	if (!cert) {
-		error_msg("Failed to parse X.509 certificate file '%s'.\n"
-			  "       Note: it must be in PEM format.",
-			  certfile);
-		display_openssl_errors();
+		error_msg_openssl("Failed to parse X.509 certificate file '%s'.\n"
+				  "       Note: it must be in PEM format.",
+				  certfile);
 	}
 	BIO_free(bio);
 	return cert;
@@ -181,33 +186,29 @@ static bool sign_data(const void *data_to_sign, size_t data_size,
 
 	p7 = PKCS7_sign(NULL, NULL, NULL, bio, pkcs7_flags);
 	if (!p7) {
-		error_msg("failed to initialize PKCS#7 signature object");
-		display_openssl_errors();
+		error_msg_openssl("failed to initialize PKCS#7 signature object");
 		goto out;
 	}
 
 	if (!PKCS7_sign_add_signer(p7, cert, pkey, md, pkcs7_flags)) {
-		error_msg("failed to add signer to PKCS#7 signature object");
-		display_openssl_errors();
+		error_msg_openssl("failed to add signer to PKCS#7 signature object");
 		goto out;
 	}
 
 	if (PKCS7_final(p7, bio, pkcs7_flags) != 1) {
-		error_msg("failed to finalize PKCS#7 signature");
-		display_openssl_errors();
+		error_msg_openssl("failed to finalize PKCS#7 signature");
 		goto out;
 	}
 
 	BIO_free(bio);
 	bio = BIO_new(BIO_s_mem());
 	if (!bio) {
-		error_msg("out of memory");
+		error_msg_openssl("out of memory");
 		goto out;
 	}
 
 	if (i2d_PKCS7_bio(bio, p7) != 1) {
-		error_msg("failed to DER-encode PKCS#7 signature object");
-		display_openssl_errors();
+		error_msg_openssl("failed to DER-encode PKCS#7 signature object");
 		goto out;
 	}
 
@@ -263,9 +264,8 @@ static bool read_signature(const char *signature_file,
 
 	p7 = d2i_PKCS7_bio(bio, NULL);
 	if (!p7) {
-		error_msg("failed to decode PKCS#7 signature from '%s'",
-			  signature_file);
-		display_openssl_errors();
+		error_msg_openssl("failed to decode PKCS#7 signature from '%s'",
+				  signature_file);
 		goto out;
 	}
 
diff --git a/util.c b/util.c
index cc5c4d4..58a2a60 100644
--- a/util.c
+++ b/util.c
@@ -67,7 +67,7 @@ char *xasprintf(const char *format, ...)
 
 /* ========== Error messages and assertions ========== */
 
-static void do_error_msg(const char *format, va_list va, int err)
+void do_error_msg(const char *format, va_list va, int err)
 {
 	fputs("ERROR: ", stderr);
 	vfprintf(stderr, format, va);
diff --git a/util.h b/util.h
index b2b18ef..049d770 100644
--- a/util.h
+++ b/util.h
@@ -8,6 +8,7 @@
 #define UTIL_H
 
 #include <inttypes.h>
+#include <stdarg.h>
 #include <stdbool.h>
 #include <stddef.h>
 
@@ -99,6 +100,7 @@ __printf(1, 2) char *xasprintf(const char *format, ...);
 
 /* ========== Error messages and assertions ========== */
 
+__cold void do_error_msg(const char *format, va_list va, int err);
 __printf(1, 2) __cold void error_msg(const char *format, ...);
 __printf(1, 2) __cold void error_msg_errno(const char *format, ...);
 __printf(1, 2) __cold __noreturn void fatal_error(const char *format, ...);