linux-kernel - [PATCH v5 09/16] module: Group section index calculations together

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Message-ID: <20240925233854.90072-10-mmaurer@google.com>
Date: Wed, 25 Sep 2024 23:38:24 +0000
From: Matthew Maurer <mmaurer@...gle.com>
To: masahiroy@...nel.org, ndesaulniers@...gle.com, ojeda@...nel.org, 
	gary@...yguo.net, mcgrof@...nel.org, Alex Gaynor <alex.gaynor@...il.com>
Cc: rust-for-linux@...r.kernel.org, linux-kbuild@...r.kernel.org, 
	linux-kernel@...r.kernel.org, neal@...pa.dev, marcan@...can.st, j@...nau.net, 
	asahi@...ts.linux.dev, linux-modules@...r.kernel.org, 
	Matthew Maurer <mmaurer@...gle.com>, Petr Pavlu <petr.pavlu@...e.com>, 
	Sami Tolvanen <samitolvanen@...gle.com>, Daniel Gomez <da.gomez@...sung.com>, 
	Boqun Feng <boqun.feng@...il.com>, 
	"Björn Roy Baron" <bjorn3_gh@...tonmail.com>, Benno Lossin <benno.lossin@...ton.me>, 
	Andreas Hindborg <a.hindborg@...nel.org>, Alice Ryhl <aliceryhl@...gle.com>, 
	Trevor Gross <tmgross@...ch.edu>
Subject: [PATCH v5 09/16] module: Group section index calculations together

Group all the index detection together to make the parent function
easier to read.

Signed-off-by: Matthew Maurer <mmaurer@...gle.com>
---
 kernel/module/main.c | 68 +++++++++++++++++++++++++++++++++-----------
 1 file changed, 51 insertions(+), 17 deletions(-)

diff --git a/kernel/module/main.c b/kernel/module/main.c
index 43140475aac0..e04a228c694a 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2039,6 +2039,56 @@ static int elf_validity_cache_index_str(struct load_info *info)
 	return 0;
 }
 
+/**
+ * elf_validity_cache_index() - Resolve, validate, cache section indices
+ * @info:  Load info to read from and update.
+ *         &load_info->sechdrs and &load_info->secstrings must be populated.
+ * @flags: Load flags, relevant to suppress version loading, see
+ *         uapi/linux/module.h
+ *
+ * Populates &load_info->index, validating as it goes.
+ * See child functions for per-field validation:
+ *
+ * * elf_validity_cache_index_info()
+ * * elf_validity_cache_index_mod()
+ * * elf_validity_cache_index_sym()
+ * * elf_validity_cache_index_str()
+ *
+ * If versioning is not suppressed via flags, load the version index from
+ * a section called "__versions" with no validation.
+ *
+ * If CONFIG_SMP is enabled, load the percpu section by name with no
+ * validation.
+ *
+ * Return: 0 on success, negative error code if an index failed validation.
+ */
+static int elf_validity_cache_index(struct load_info *info, int flags)
+{
+	int err;
+
+	err = elf_validity_cache_index_info(info);
+	if (err < 0)
+		return err;
+	err = elf_validity_cache_index_mod(info);
+	if (err < 0)
+		return err;
+	err = elf_validity_cache_index_sym(info);
+	if (err < 0)
+		return err;
+	err = elf_validity_cache_index_str(info);
+	if (err < 0)
+		return err;
+
+	if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
+		info->index.vers = 0; /* Pretend no __versions section! */
+	else
+		info->index.vers = find_sec(info, "__versions");
+
+	info->index.pcpu = find_pcpusec(info);
+
+	return 0;
+}
+
 /*
  * Check userspace passed ELF module against our expectations, and cache
  * useful variables for further processing as we go.
@@ -2069,16 +2119,7 @@ static int elf_validity_cache_copy(struct load_info *info, int flags)
 	err = elf_validity_cache_secstrings(info);
 	if (err < 0)
 		return err;
-	err = elf_validity_cache_index_info(info);
-	if (err < 0)
-		return err;
-	err = elf_validity_cache_index_mod(info);
-	if (err < 0)
-		return err;
-	err = elf_validity_cache_index_sym(info);
-	if (err < 0)
-		return err;
-	err = elf_validity_cache_index_str(info);
+	err = elf_validity_cache_index(info, flags);
 	if (err < 0)
 		return err;
 
@@ -2095,13 +2136,6 @@ static int elf_validity_cache_copy(struct load_info *info, int flags)
 	if (!info->name)
 		info->name = info->mod->name;
 
-	if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
-		info->index.vers = 0; /* Pretend no __versions section! */
-	else
-		info->index.vers = find_sec(info, "__versions");
-
-	info->index.pcpu = find_pcpusec(info);
-
 	return 0;
 }
 
-- 
2.46.1.824.gd892dcdcdd-goog