3.2.102-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Eric Biggers <ebiggers@xxxxxxxxxx>
commit a208fa8f33031b9e0aba44c7d1b7e68eb0cbd29e upstream.
We need to consistently enforce that keyed hashes cannot be used without
setting the key. To do this we need a reliable way to determine whether
a given hash algorithm is keyed or not. AF_ALG currently does this by
checking for the presence of a ->setkey() method. However, this is
actually slightly broken because the CRC-32 algorithms implement
->setkey() but can also be used without a key. (The CRC-32 "key" is not
actually a cryptographic key but rather represents the initial state.
If not overridden, then a default initial state is used.)
Prepare to fix this by introducing a flag CRYPTO_ALG_OPTIONAL_KEY which
indicates that the algorithm has a ->setkey() method, but it is not
required to be called. Then set it on all the CRC-32 algorithms.
The same also applies to the Adler-32 implementation in Lustre.
Also, the cryptd and mcryptd templates have to pass through the flag
from their underlying algorithm.
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
[bwh: Backported to 3.2:
- Drop changes to nonexistent drivers
- There's no CRYPTO_ALG_INTERNAL flag
- Adjust filenames]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/arch/x86/crypto/crc32c-intel.c
+++ b/arch/x86/crypto/crc32c-intel.c
@@ -166,6 +166,7 @@ static struct shash_alg alg = {
.cra_name = "crc32c",
.cra_driver_name = "crc32c-intel",
.cra_priority = 200,
+ .cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
.cra_blocksize = CHKSUM_BLOCK_SIZE,
.cra_ctxsize = sizeof(u32),
.cra_module = THIS_MODULE,
--- a/crypto/crc32c.c
+++ b/crypto/crc32c.c
@@ -234,6 +234,7 @@ static struct shash_alg alg = {
.cra_name = "crc32c",
.cra_driver_name = "crc32c-generic",
.cra_priority = 100,
+ .cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
.cra_blocksize = CHKSUM_BLOCK_SIZE,
.cra_alignmask = 3,
.cra_ctxsize = sizeof(struct chksum_ctx),
--- a/crypto/cryptd.c
+++ b/crypto/cryptd.c
@@ -603,7 +603,8 @@ static int cryptd_create_hash(struct cry
if (err)
goto out_free_inst;
- inst->alg.halg.base.cra_flags = CRYPTO_ALG_ASYNC;
+ inst->alg.halg.base.cra_flags = CRYPTO_ALG_ASYNC |
+ (alg->cra_flags & CRYPTO_ALG_OPTIONAL_KEY);
inst->alg.halg.digestsize = salg->digestsize;
inst->alg.halg.base.cra_ctxsize = sizeof(struct cryptd_hash_ctx);
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -89,6 +89,12 @@
#define CRYPTO_ALG_INSTANCE 0x00000800
/*
+ * Set if the algorithm has a ->setkey() method but can be used without
+ * calling it first, i.e. there is a default key.
+ */
+#define CRYPTO_ALG_OPTIONAL_KEY 0x00004000
+
+/*
* Transform masks and values (for crt_flags).
*/
#define CRYPTO_TFM_REQ_MASK 0x000fff00
