Trivial renaming diff that adds a bit of documentation. As already
mentioned, ta_parse() doesn't parse the TA, it deserializes the TAL's
SPKI and compares internal representations. This isn't quite right but
libcrypto often makes things that should be easy almost impossible.
Since I forgot this and wasted a lot of time at least twice in this
specific instance, leave an explicit comment on this in ta_check_pubkey().

Index: usr.sbin/rpki-client/cert.c
===================================================================
RCS file: /cvs/src/usr.sbin/rpki-client/cert.c,v
diff -u -p -r1.218 cert.c
--- usr.sbin/rpki-client/cert.c	27 Jan 2026 08:40:29 -0000	1.218
+++ usr.sbin/rpki-client/cert.c	28 Jan 2026 07:30:56 -0000
@@ -1991,7 +1991,11 @@ ta_check_pubkey(const char *fn, struct c
 	EVP_PKEY	*cert_pkey, *tal_pkey;
 	int		 rv = 0;
 
-	/* first check pubkey against the one from the TAL */
+	/*
+	 * We should really verify that the TAL's SPKI is byte-identical with
+	 * the cert's SPKI. There's no sane way to access the original DER, so
+	 * comparing internal representations is the best we can do.
+	 */
 	tal_pkey = d2i_PUBKEY(NULL, &spki, spkisz);
 	if (tal_pkey == NULL) {
 		warnx("%s: RFC 6487 (trust anchor): bad TAL pubkey", fn);
@@ -2039,9 +2043,15 @@ ta_check_validity(const char *fn, struct
 	return 1;
 }
 
+/*
+ * Validate a TA against the subjectPublicKeyInfo from the TAL.
+ * Check that the SPKIs match, and that the cert is self-signed
+ * and currently valid.
+ * Returns cert passed in on success or NULL on failure.
+ */
 struct cert *
-ta_parse(const char *fn, struct cert *p, const unsigned char *spki,
-    size_t spkisz)
+ta_validate(const char *fn, struct cert *p, const unsigned char *spki,
+     size_t spkisz)
 {
 	if (p == NULL)
 		return NULL;
@@ -2082,7 +2092,7 @@ cert_parse_ta(const char *fn, const unsi
 	if ((cert = cert_deserialize_and_parse(fn, der, len)) == NULL)
 		return NULL;
 
-	return ta_parse(fn, cert, spki, spkisz);
+	return ta_validate(fn, cert, spki, spkisz);
 }
 
 /*
Index: usr.sbin/rpki-client/extern.h
===================================================================
RCS file: /cvs/src/usr.sbin/rpki-client/extern.h,v
diff -u -p -r1.275 extern.h
--- usr.sbin/rpki-client/extern.h	27 Jan 2026 08:40:29 -0000	1.275
+++ usr.sbin/rpki-client/extern.h	28 Jan 2026 07:30:56 -0000
@@ -720,7 +720,7 @@ struct cert	*cert_parse_ee_cert(const ch
 struct cert	*cert_parse_ta(const char *, const unsigned char *, size_t,
 		    const unsigned char *, size_t);
 struct cert	*cert_parse(const char *, const unsigned char *, size_t);
-struct cert	*ta_parse(const char *, struct cert *, const unsigned char *,
+struct cert	*ta_validate(const char *, struct cert *, const unsigned char *,
 		    size_t);
 struct cert	*cert_read(struct ibuf *);
 void		 cert_insert_brks(struct brk_tree *, struct cert *);
Index: usr.sbin/rpki-client/filemode.c
===================================================================
RCS file: /cvs/src/usr.sbin/rpki-client/filemode.c,v
diff -u -p -r1.79 filemode.c
--- usr.sbin/rpki-client/filemode.c	27 Jan 2026 08:40:29 -0000	1.79
+++ usr.sbin/rpki-client/filemode.c	28 Jan 2026 07:30:56 -0000
@@ -612,7 +612,7 @@ proc_parser_file(char *file, unsigned ch
 		expires = NULL;
 		notafter = NULL;
 		if ((tal = find_tal(cert)) != NULL) {
-			cert = ta_parse(file, cert, tal->spki, tal->spkisz);
+			cert = ta_validate(file, cert, tal->spki, tal->spkisz);
 			status = (cert != NULL);
 			if (status) {
 				expires = &cert->expires;
Index: regress/usr.sbin/rpki-client/test-cert.c
===================================================================
RCS file: /cvs/src/regress/usr.sbin/rpki-client/test-cert.c,v
diff -u -p -r1.28 test-cert.c
--- regress/usr.sbin/rpki-client/test-cert.c	20 Jan 2026 16:49:44 -0000	1.28
+++ regress/usr.sbin/rpki-client/test-cert.c	28 Jan 2026 07:30:56 -0000
@@ -85,7 +85,7 @@ main(int argc, char *argv[])
 			free(buf);
 			if (p == NULL)
 				break;
-			p = ta_parse(cert_path, p, tal->spki, tal->spkisz);
+			p = ta_validate(cert_path, p, tal->spki, tal->spkisz);
 			tal_free(tal);
 			if (p == NULL)
 				break;