From: Timo Sirainen <timo.sirainen@dovecot.fi>
Date: Mon, 13 Feb 2017 21:46:15 +0000 (+0200)
Subject: lib: Add pool_alloconly_create_clean()
X-Git-Tag: 2.3.0.rc1~2125
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c2664306fcea8bcaafd19a6d1b683ef0ad0ece91;p=thirdparty%2Fdovecot%2Fcore.git

lib: Add pool_alloconly_create_clean()

This partially reverts 2a2beae3a4c1e75b3aeff996781503138e6f24bc
---

diff --git a/src/lib/mempool-alloconly.c b/src/lib/mempool-alloconly.c
index 40594ff30b..5b0a5e9f55 100644
--- a/src/lib/mempool-alloconly.c
+++ b/src/lib/mempool-alloconly.c
@@ -24,6 +24,7 @@ struct alloconly_pool {
 	size_t base_size;
 	bool disable_warning;
 #endif
+	bool clean_frees;
 };
 
 struct pool_block {
@@ -159,6 +160,17 @@ pool_t pool_alloconly_create(const char *name ATTR_UNUSED, size_t size)
 	return &new_apool->pool;
 }
 
+pool_t pool_alloconly_create_clean(const char *name, size_t size)
+{
+	struct alloconly_pool *apool;
+	pool_t pool;
+
+	pool = pool_alloconly_create(name, size);
+	apool = (struct alloconly_pool *)pool;
+	apool->clean_frees = TRUE;
+	return pool;
+}
+
 static void pool_alloconly_destroy(struct alloconly_pool *apool)
 {
 	void *block;
@@ -170,7 +182,13 @@ static void pool_alloconly_destroy(struct alloconly_pool *apool)
 	block = apool->block;
 #ifdef DEBUG
 	safe_memset(block, CLEAR_CHR, SIZEOF_POOLBLOCK + apool->block->size);
+#else
+	if (apool->clean_frees) {
+		safe_memset(block, CLEAR_CHR,
+			    SIZEOF_POOLBLOCK + apool->block->size);
+	}
 #endif
+
 #ifndef USE_GC
 	free(block);
 #endif
@@ -362,6 +380,11 @@ static void pool_alloconly_clear(pool_t pool)
 
 #ifdef DEBUG
 		safe_memset(block, CLEAR_CHR, SIZEOF_POOLBLOCK + block->size);
+#else
+		if (apool->clean_frees) {
+			safe_memset(block, CLEAR_CHR,
+				    SIZEOF_POOLBLOCK + block->size);
+		}
 #endif
 #ifndef USE_GC
 		free(block);
diff --git a/src/lib/mempool.h b/src/lib/mempool.h
index c796a0a9e0..da7583d9ef 100644
--- a/src/lib/mempool.h
+++ b/src/lib/mempool.h
@@ -57,6 +57,11 @@ extern pool_t unsafe_data_stack_pool;
 /* Create a new alloc-only pool. Note that `size' specifies the initial
    malloc()ed block size, part of it is used internally. */
 pool_t pool_alloconly_create(const char *name, size_t size);
+/* Like alloconly pool, but clear the memory before freeing it. The idea is
+   that you could allocate memory for storing sensitive information from this
+   pool, and be sure that it gets cleared from the memory when it's no longer
+   needed. */
+pool_t pool_alloconly_create_clean(const char *name, size_t size);
 
 /* When allocating memory from returned pool, the data stack frame must be
    the same as it was when calling this function. pool_unref() also checks