Merge tag 'modules-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux

Pull module updates from Petr Pavlu:

 - Make .static_call_sites in modules read-only after init

   The .static_call_sites sections in modules have been made read-only
   after init to avoid any (non-)accidental modifications, similarly to
   how they are read-only after init in vmlinux

 - The rest are minor cleanups

* tag 'modules-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux:
  module: Remove outdated comment about text_size
  module: Make .static_call_sites read-only after init
  module: Add a separate function to mark sections as read-only after init
  module: Constify parameters of module_enforce_rwx_sections()

3 files changed, 57 insertions, 24 deletions

diff --git a/kernel/module/internal.h b/kernel/module/internal.h
index 626cf8668a7e..8d74b0a21c82 100644
--- a/kernel/module/internal.h
+++ b/kernel/module/internal.h
@@ -322,8 +322,11 @@ int module_enable_rodata_ro(const struct module *mod);
 int module_enable_rodata_ro_after_init(const struct module *mod);
 int module_enable_data_nx(const struct module *mod);
 int module_enable_text_rox(const struct module *mod);
-int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
-				char *secstrings, struct module *mod);
+int module_enforce_rwx_sections(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
+				const char *secstrings,
+				const struct module *mod);
+void module_mark_ro_after_init(const Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+			       const char *secstrings);
 
 #ifdef CONFIG_MODULE_SIG
 int module_sig_check(struct load_info *info, int flags);
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 5c6ab20240a6..3d64e69cc03e 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -1562,12 +1562,11 @@ static void __layout_sections(struct module *mod, struct load_info *info, bool i
 {
 	unsigned int m, i;
 
+	/*
+	 * { Mask of required section header flags,
+	 *   Mask of excluded section header flags }
+	 */
 	static const unsigned long masks[][2] = {
-		/*
-		 * NOTE: all executable code must be the first section
-		 * in this array; otherwise modify the text_size
-		 * finder in the two loops below
-		 */
 		{ SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL },
 		{ SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL },
 		{ SHF_RO_AFTER_INIT | SHF_ALLOC, ARCH_SHF_SMALL },
@@ -2768,7 +2767,6 @@ core_param(module_blacklist, module_blacklist, charp, 0400);
 static struct module *layout_and_allocate(struct load_info *info, int flags)
 {
 	struct module *mod;
-	unsigned int ndx;
 	int err;
 
 	/* Allow arches to frob section contents and sizes.  */
@@ -2786,22 +2784,11 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
 	info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC;
 
 	/*
-	 * Mark ro_after_init section with SHF_RO_AFTER_INIT so that
-	 * layout_sections() can put it in the right place.
+	 * Mark relevant sections as SHF_RO_AFTER_INIT so layout_sections() can
+	 * put them in the right place.
 	 * Note: ro_after_init sections also have SHF_{WRITE,ALLOC} set.
 	 */
-	ndx = find_sec(info, ".data..ro_after_init");
-	if (ndx)
-		info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
-	/*
-	 * Mark the __jump_table section as ro_after_init as well: these data
-	 * structures are never modified, with the exception of entries that
-	 * refer to code in the __init section, which are annotated as such
-	 * at module load time.
-	 */
-	ndx = find_sec(info, "__jump_table");
-	if (ndx)
-		info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
+	module_mark_ro_after_init(info->hdr, info->sechdrs, info->secstrings);
 
 	/*
 	 * Determine total sizes, and put offsets in sh_entsize.  For now
diff --git a/kernel/module/strict_rwx.c b/kernel/module/strict_rwx.c
index 03f4142cfbf4..8fd438529fbc 100644
--- a/kernel/module/strict_rwx.c
+++ b/kernel/module/strict_rwx.c
@@ -87,8 +87,9 @@ int module_enable_data_nx(const struct module *mod)
 	return 0;
 }
 
-int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
-				char *secstrings, struct module *mod)
+int module_enforce_rwx_sections(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
+				const char *secstrings,
+				const struct module *mod)
 {
 	const unsigned long shf_wx = SHF_WRITE | SHF_EXECINSTR;
 	int i;
@@ -106,3 +107,45 @@ int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
 
 	return 0;
 }
+
+static const char *const ro_after_init[] = {
+	/*
+	 * Section .data..ro_after_init holds data explicitly annotated by
+	 * __ro_after_init.
+	 */
+	".data..ro_after_init",
+
+	/*
+	 * Section __jump_table holds data structures that are never modified,
+	 * with the exception of entries that refer to code in the __init
+	 * section, which are marked as such at module load time.
+	 */
+	"__jump_table",
+
+#ifdef CONFIG_HAVE_STATIC_CALL_INLINE
+	/*
+	 * Section .static_call_sites holds data structures that need to be
+	 * sorted and processed at module load time but are never modified
+	 * afterwards.
+	 */
+	".static_call_sites",
+#endif
+};
+
+void module_mark_ro_after_init(const Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+			       const char *secstrings)
+{
+	int i, j;
+
+	for (i = 1; i < hdr->e_shnum; i++) {
+		Elf_Shdr *shdr = &sechdrs[i];
+
+		for (j = 0; j < ARRAY_SIZE(ro_after_init); j++) {
+			if (strcmp(secstrings + shdr->sh_name,
+				   ro_after_init[j]) == 0) {
+				shdr->sh_flags |= SHF_RO_AFTER_INIT;
+				break;
+			}
+		}
+	}
+}