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[Qemu-devel] [PULL 11/11] crypto: avoid undefined behavior in nettle cal
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PULL 11/11] crypto: avoid undefined behavior in nettle calls |
Date: |
Thu, 16 Jul 2015 18:55:58 +0200 |
From: Radim Krčmář <address@hidden>
Calling a function pointer that was cast from an incompatible function
results in undefined behavior. 'void *' isn't compatible with 'struct
XXX *', so we can't cast to nettle_cipher_func, but have to provide a
wrapper. (Conversion from 'void *' to 'struct XXX *' might require
computation, which won't be done if we drop argument's true type, and
pointers can have different sizes so passing arguments on stack would
bug.)
Having two different prototypes based on nettle version doesn't make
this solution any nicer.
Reported-by: Peter Maydell <address@hidden>
Signed-off-by: Radim Krčmář <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
crypto/cipher-nettle.c | 43 +++++++++++++++++++++++++++++++++++++++----
1 file changed, 39 insertions(+), 4 deletions(-)
diff --git a/crypto/cipher-nettle.c b/crypto/cipher-nettle.c
index e61aaa2..a55a8e8 100644
--- a/crypto/cipher-nettle.c
+++ b/crypto/cipher-nettle.c
@@ -25,8 +25,43 @@
#if CONFIG_NETTLE_VERSION_MAJOR < 3
typedef nettle_crypt_func nettle_cipher_func;
+
+typedef void * cipher_ctx_t;
+typedef unsigned cipher_length_t;
+#else
+typedef const void * cipher_ctx_t;
+typedef size_t cipher_length_t;
#endif
+static nettle_cipher_func aes_encrypt_wrapper;
+static nettle_cipher_func aes_decrypt_wrapper;
+static nettle_cipher_func des_encrypt_wrapper;
+static nettle_cipher_func des_decrypt_wrapper;
+
+static void aes_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+ uint8_t *dst, const uint8_t *src)
+{
+ aes_encrypt(ctx, length, dst, src);
+}
+
+static void aes_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+ uint8_t *dst, const uint8_t *src)
+{
+ aes_encrypt(ctx, length, dst, src);
+}
+
+static void des_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+ uint8_t *dst, const uint8_t *src)
+{
+ des_encrypt(ctx, length, dst, src);
+}
+
+static void des_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+ uint8_t *dst, const uint8_t *src)
+{
+ des_decrypt(ctx, length, dst, src);
+}
+
typedef struct QCryptoCipherNettle QCryptoCipherNettle;
struct QCryptoCipherNettle {
void *ctx_encrypt;
@@ -87,8 +122,8 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
des_set_key(ctx->ctx_encrypt, rfbkey);
g_free(rfbkey);
- ctx->alg_encrypt = (nettle_cipher_func *)des_encrypt;
- ctx->alg_decrypt = (nettle_cipher_func *)des_decrypt;
+ ctx->alg_encrypt = des_encrypt_wrapper;
+ ctx->alg_decrypt = des_decrypt_wrapper;
ctx->niv = DES_BLOCK_SIZE;
break;
@@ -102,8 +137,8 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm
alg,
aes_set_encrypt_key(ctx->ctx_encrypt, nkey, key);
aes_set_decrypt_key(ctx->ctx_decrypt, nkey, key);
- ctx->alg_encrypt = (nettle_cipher_func *)aes_encrypt;
- ctx->alg_decrypt = (nettle_cipher_func *)aes_decrypt;
+ ctx->alg_encrypt = aes_encrypt_wrapper;
+ ctx->alg_decrypt = aes_decrypt_wrapper;
ctx->niv = AES_BLOCK_SIZE;
break;
--
2.4.3
- [Qemu-devel] [PULL 01/11] mips/kvm: Fix Big endian 32-bit register access, (continued)
- [Qemu-devel] [PULL 01/11] mips/kvm: Fix Big endian 32-bit register access, Paolo Bonzini, 2015/07/16
- [Qemu-devel] [PULL 02/11] mips/kvm: Sign extend registers written to KVM, Paolo Bonzini, 2015/07/16
- [Qemu-devel] [PULL 03/11] ppc/spapr_drc: fix memory leak, Paolo Bonzini, 2015/07/16
- [Qemu-devel] [PULL 04/11] arm/xlnx-zynqmp: fix memory leak, Paolo Bonzini, 2015/07/16
- [Qemu-devel] [PULL 05/11] RDMA: Fix error exits, Paolo Bonzini, 2015/07/16
- [Qemu-devel] [PULL 07/11] rcu: actually register threads that have RCU read-side critical sections, Paolo Bonzini, 2015/07/16
- [Qemu-devel] [PULL 06/11] rcu: automatically unregister threads when they exit, Paolo Bonzini, 2015/07/16
- [Qemu-devel] [PULL 08/11] rcu: detect missing rcu_register_thread(), Paolo Bonzini, 2015/07/16
- [Qemu-devel] [PULL 10/11] crypto: fix build with nettle >= 3.0.0, Paolo Bonzini, 2015/07/16
- [Qemu-devel] [PULL 09/11] memory: fix refcount leak in memory_region_present, Paolo Bonzini, 2015/07/16
- [Qemu-devel] [PULL 11/11] crypto: avoid undefined behavior in nettle calls,
Paolo Bonzini <=
- Re: [Qemu-devel] [PULL 00/11] RCU, KVM, memory API, crypto, Coverity fixes for 2.4.0-rc1, Peter Maydell, 2015/07/16