linux-kernel - [PATCH 01/15] crypto - Avoid free() namespace collision

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Date:   Thu, 30 Apr 2020 23:30:43 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     linux-kernel@...r.kernel.org,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>
Cc:     Arnd Bergmann <arnd@...db.de>, Eric Biggers <ebiggers@...gle.com>,
        Ard Biesheuvel <ardb@...nel.org>, linux-crypto@...r.kernel.org
Subject: [PATCH 01/15] crypto - Avoid free() namespace collision

gcc-10 complains about using the name of a standard library
function in the kernel, as we are not building with -ffreestanding:

crypto/xts.c:325:13: error: conflicting types for built-in function 'free'; expected 'void(void *)' [-Werror=builtin-declaration-mismatch]
  325 | static void free(struct skcipher_instance *inst)
      |             ^~~~
crypto/lrw.c:290:13: error: conflicting types for built-in function 'free'; expected 'void(void *)' [-Werror=builtin-declaration-mismatch]
  290 | static void free(struct skcipher_instance *inst)
      |             ^~~~
crypto/lrw.c:27:1: note: 'free' is declared in header '<stdlib.h>'

The xts and lrw cipher implementations run into this because they do
not use the conventional namespaced function names.

It might be better to rename all local functions in those files to
help with things like 'ctags' and 'grep', but just renaming these two
avoids the build issue. I picked the more verbose crypto_xts_free()
and crypto_lrw_free() names for consistency with several other drivers
that do use namespaced function names.

Fixes: f1c131b45410 ("crypto: xts - Convert to skcipher")
Fixes: 700cb3f5fe75 ("crypto: lrw - Convert to skcipher")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 crypto/lrw.c | 6 +++---
 crypto/xts.c | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/crypto/lrw.c b/crypto/lrw.c
index 376d7ed3f1f8..5b07a7c09296 100644
--- a/crypto/lrw.c
+++ b/crypto/lrw.c
@@ -287,7 +287,7 @@ static void exit_tfm(struct crypto_skcipher *tfm)
 	crypto_free_skcipher(ctx->child);
 }
 
-static void free(struct skcipher_instance *inst)
+static void crypto_lrw_free(struct skcipher_instance *inst)
 {
 	crypto_drop_skcipher(skcipher_instance_ctx(inst));
 	kfree(inst);
@@ -400,12 +400,12 @@ static int create(struct crypto_template *tmpl, struct rtattr **tb)
 	inst->alg.encrypt = encrypt;
 	inst->alg.decrypt = decrypt;
 
-	inst->free = free;
+	inst->free = crypto_lrw_free;
 
 	err = skcipher_register_instance(tmpl, inst);
 	if (err) {
 err_free_inst:
-		free(inst);
+		crypto_lrw_free(inst);
 	}
 	return err;
 }
diff --git a/crypto/xts.c b/crypto/xts.c
index dbdd8af629e6..3565f3b863a6 100644
--- a/crypto/xts.c
+++ b/crypto/xts.c
@@ -322,7 +322,7 @@ static void exit_tfm(struct crypto_skcipher *tfm)
 	crypto_free_cipher(ctx->tweak);
 }
 
-static void free(struct skcipher_instance *inst)
+static void crypto_xts_free(struct skcipher_instance *inst)
 {
 	crypto_drop_skcipher(skcipher_instance_ctx(inst));
 	kfree(inst);
@@ -434,12 +434,12 @@ static int create(struct crypto_template *tmpl, struct rtattr **tb)
 	inst->alg.encrypt = encrypt;
 	inst->alg.decrypt = decrypt;
 
-	inst->free = free;
+	inst->free = crypto_xts_free;
 
 	err = skcipher_register_instance(tmpl, inst);
 	if (err) {
 err_free_inst:
-		free(inst);
+		crypto_xts_free(inst);
 	}
 	return err;
 }
-- 
2.26.0