linux-kernel - [PATCH v4 12/17] module: Move signature splitting up

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Message-Id: <20260113-module-hashes-v4-12-0b932db9b56b@weissschuh.net>
Date: Tue, 13 Jan 2026 13:28:56 +0100
From: Thomas Weißschuh <linux@...ssschuh.net>
To: Nathan Chancellor <nathan@...nel.org>, Arnd Bergmann <arnd@...db.de>, 
 Luis Chamberlain <mcgrof@...nel.org>, Petr Pavlu <petr.pavlu@...e.com>, 
 Sami Tolvanen <samitolvanen@...gle.com>, 
 Daniel Gomez <da.gomez@...sung.com>, Paul Moore <paul@...l-moore.com>, 
 James Morris <jmorris@...ei.org>, "Serge E. Hallyn" <serge@...lyn.com>, 
 Jonathan Corbet <corbet@....net>, Madhavan Srinivasan <maddy@...ux.ibm.com>, 
 Michael Ellerman <mpe@...erman.id.au>, Nicholas Piggin <npiggin@...il.com>, 
 Naveen N Rao <naveen@...nel.org>, Mimi Zohar <zohar@...ux.ibm.com>, 
 Roberto Sassu <roberto.sassu@...wei.com>, 
 Dmitry Kasatkin <dmitry.kasatkin@...il.com>, 
 Eric Snowberg <eric.snowberg@...cle.com>, 
 Nicolas Schier <nicolas.schier@...ux.dev>, 
 Daniel Gomez <da.gomez@...nel.org>, Aaron Tomlin <atomlin@...mlin.com>, 
 "Christophe Leroy (CS GROUP)" <chleroy@...nel.org>, 
 Nicolas Schier <nsc@...nel.org>, 
 Nicolas Bouchinet <nicolas.bouchinet@....cyber.gouv.fr>, 
 Xiu Jianfeng <xiujianfeng@...wei.com>, Nicolas Schier <nsc@...nel.org>, 
 Christophe Leroy <chleroy@...nel.org>
Cc: Fabian Grünbichler <f.gruenbichler@...xmox.com>, 
 Arnout Engelen <arnout@...t.net>, Mattia Rizzolo <mattia@...reri.org>, 
 kpcyrd <kpcyrd@...hlinux.org>, Christian Heusel <christian@...sel.eu>, 
 Câju Mihai-Drosi <mcaju95@...il.com>, 
 Sebastian Andrzej Siewior <bigeasy@...utronix.de>, 
 linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-arch@...r.kernel.org, linux-modules@...r.kernel.org, 
 linux-security-module@...r.kernel.org, linux-doc@...r.kernel.org, 
 linuxppc-dev@...ts.ozlabs.org, linux-integrity@...r.kernel.org, 
 Thomas Weißschuh <linux@...ssschuh.net>
Subject: [PATCH v4 12/17] module: Move signature splitting up

The signature splitting will also be used by CONFIG_MODULE_HASHES.

Move it up the callchain, so the result can be reused.

Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
---
 kernel/module/internal.h |  2 +-
 kernel/module/main.c     | 13 ++++++++++++-
 kernel/module/signing.c  | 21 +++++++--------------
 3 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/kernel/module/internal.h b/kernel/module/internal.h
index e053c29a5d08..e2d49122c2a1 100644
--- a/kernel/module/internal.h
+++ b/kernel/module/internal.h
@@ -337,7 +337,7 @@ int module_enforce_rwx_sections(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
 void module_mark_ro_after_init(const Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
 			       const char *secstrings);

-int module_sig_check(struct load_info *info, int flags);
+int module_sig_check(struct load_info *info, const u8 *sig, size_t sig_len);

 #ifdef CONFIG_DEBUG_KMEMLEAK
 void kmemleak_load_module(const struct module *mod, const struct load_info *info);
diff --git a/kernel/module/main.c b/kernel/module/main.c
index c09b25c0166a..d65bc300a78c 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -3346,10 +3346,21 @@ static int early_mod_check(struct load_info *info, int flags)

 static int module_integrity_check(struct load_info *info, int flags)
 {
+	bool mangled_module = flags & (MODULE_INIT_IGNORE_MODVERSIONS |
+				       MODULE_INIT_IGNORE_VERMAGIC);
+	size_t sig_len;
+	const u8 *sig;
 	int err = 0;

+	if (IS_ENABLED(CONFIG_MODULE_SIG_POLICY)) {
+		err = mod_split_sig(info->hdr, &info->len, mangled_module,
+				    &sig_len, &sig, "module");
+		if (err)
+			return err;
+	}
+
 	if (IS_ENABLED(CONFIG_MODULE_SIG))
-		err = module_sig_check(info, flags);
+		err = module_sig_check(info, sig, sig_len);

 	if (err)
 		return err;
diff --git a/kernel/module/signing.c b/kernel/module/signing.c
index 8a5f66389116..86164761cac7 100644
--- a/kernel/module/signing.c
+++ b/kernel/module/signing.c
@@ -15,26 +15,19 @@
 #include <uapi/linux/module.h>
 #include "internal.h"

-int module_sig_check(struct load_info *info, int flags)
+int module_sig_check(struct load_info *info, const u8 *sig, size_t sig_len)
 {
 	int err;
 	const char *reason;
 	const void *mod = info->hdr;
-	size_t sig_len;
-	const u8 *sig;
-	bool mangled_module = flags & (MODULE_INIT_IGNORE_MODVERSIONS |
-				       MODULE_INIT_IGNORE_VERMAGIC);

-	err = mod_split_sig(info->hdr, &info->len, mangled_module, &sig_len, &sig, "module");
+	err = verify_pkcs7_signature(mod, info->len, sig, sig_len,
+				     VERIFY_USE_SECONDARY_KEYRING,
+				     VERIFYING_MODULE_SIGNATURE,
+				     NULL, NULL);
 	if (!err) {
-		err = verify_pkcs7_signature(mod, info->len, sig, sig_len,
-					     VERIFY_USE_SECONDARY_KEYRING,
-					     VERIFYING_MODULE_SIGNATURE,
-					     NULL, NULL);
-		if (!err) {
-			info->sig_ok = true;
-			return 0;
-		}
+		info->sig_ok = true;
+		return 0;
 	}

 	/*

-- 
2.52.0