From 47a92dfbe01f41bcbf359250ccb3caa589763abf Mon Sep 17 00:00:00 2001
From: Suren Baghdasaryan <surenb@google.com>
Date: Thu, 21 Mar 2024 09:36:34 -0700
Subject: lib: prevent module unloading if memory is not freed
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Skip freeing module's data section if there are non-zero allocation tags
because otherwise, once these allocations are freed, the access to their
code tag would cause UAF.

Link: https://lkml.kernel.org/r/20240321163705.3067592-13-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Tested-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Andreas Hindborg <a.hindborg@samsung.com>
Cc: Benno Lossin <benno.lossin@proton.me>
Cc: "Björn Roy Baron" <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Gary Guo <gary@garyguo.net>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 lib/codetag.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

(limited to 'lib/codetag.c')

diff --git a/lib/codetag.c b/lib/codetag.c
index 54d2828eba25..408062f722ce 100644
--- a/lib/codetag.c
+++ b/lib/codetag.c
@@ -5,6 +5,7 @@
 #include <linux/module.h>
 #include <linux/seq_buf.h>
 #include <linux/slab.h>
+#include <linux/vmalloc.h>
 
 struct codetag_type {
 	struct list_head link;
@@ -206,12 +207,13 @@ void codetag_load_module(struct module *mod)
 	mutex_unlock(&codetag_lock);
 }
 
-void codetag_unload_module(struct module *mod)
+bool codetag_unload_module(struct module *mod)
 {
 	struct codetag_type *cttype;
+	bool unload_ok = true;
 
 	if (!mod)
-		return;
+		return true;
 
 	mutex_lock(&codetag_lock);
 	list_for_each_entry(cttype, &codetag_types, link) {
@@ -228,7 +230,8 @@ void codetag_unload_module(struct module *mod)
 		}
 		if (found) {
 			if (cttype->desc.module_unload)
-				cttype->desc.module_unload(cttype, cmod);
+				if (!cttype->desc.module_unload(cttype, cmod))
+					unload_ok = false;
 
 			cttype->count -= range_size(cttype, &cmod->range);
 			idr_remove(&cttype->mod_idr, mod_id);
@@ -237,6 +240,8 @@ void codetag_unload_module(struct module *mod)
 		up_write(&cttype->mod_lock);
 	}
 	mutex_unlock(&codetag_lock);
+
+	return unload_ok;
 }
 
 #else /* CONFIG_MODULES */
-- 
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