BACKPORT: crypto: chacha20 - Fix keystream alignment for chacha20_block()
When chacha20_block() outputs the keystream block, it uses 'u32' stores
directly. However, the callers (crypto/chacha20_generic.c and
drivers/char/random.c) declare the keystream buffer as a 'u8' array,
which is not guaranteed to have the needed alignment.
Fix it by having both callers declare the keystream as a 'u32' array.
For now this is preferable to switching over to the unaligned access
macros because chacha20_block() is only being used in cases where we can
easily control the alignment (stack buffers).
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
(cherry picked from commit 9f480faec58cd6197a007ea1dcac6b7c3daf1139)
Conflicts:
drivers/char/random.c
Bug: 112008522
Test: As series, see Ic61c13b53facfd2173065be715a7ee5f3af8760b
Change-Id: I7557b2ca2ace0e19e97e997659857b3fa7a2b540
Signed-off-by: Eric Biggers <ebiggers@google.com>
diff --git a/crypto/chacha20_generic.c b/crypto/chacha20_generic.c
index 8c8befb..1a48d3a 100644
--- a/crypto/chacha20_generic.c
+++ b/crypto/chacha20_generic.c
@@ -19,20 +19,20 @@
static void chacha20_docrypt(u32 *state, u8 *dst, const u8 *src,
unsigned int bytes)
{
- u8 stream[CHACHA20_BLOCK_SIZE];
+ u32 stream[CHACHA20_BLOCK_WORDS];
if (dst != src)
memcpy(dst, src, bytes);
while (bytes >= CHACHA20_BLOCK_SIZE) {
chacha20_block(state, stream);
- crypto_xor(dst, stream, CHACHA20_BLOCK_SIZE);
+ crypto_xor(dst, (const u8 *)stream, CHACHA20_BLOCK_SIZE);
bytes -= CHACHA20_BLOCK_SIZE;
dst += CHACHA20_BLOCK_SIZE;
}
if (bytes) {
chacha20_block(state, stream);
- crypto_xor(dst, stream, bytes);
+ crypto_xor(dst, (const u8 *)stream, bytes);
}
}
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 81b65d0..4fc600d 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -440,9 +440,9 @@
static unsigned long crng_global_init_time = 0;
#define CRNG_INIT_CNT_THRESH (2*CHACHA20_KEY_SIZE)
static void _extract_crng(struct crng_state *crng,
- __u8 out[CHACHA20_BLOCK_SIZE]);
+ __u32 out[CHACHA20_BLOCK_WORDS]);
static void _crng_backtrack_protect(struct crng_state *crng,
- __u8 tmp[CHACHA20_BLOCK_SIZE], int used);
+ __u32 tmp[CHACHA20_BLOCK_WORDS], int used);
static void process_random_ready_list(void);
static struct ratelimit_state unseeded_warning =
@@ -868,7 +868,7 @@
unsigned long flags;
int i, num;
union {
- __u8 block[CHACHA20_BLOCK_SIZE];
+ __u32 block[CHACHA20_BLOCK_WORDS];
__u32 key[8];
} buf;
@@ -926,7 +926,7 @@
}
static void _extract_crng(struct crng_state *crng,
- __u8 out[CHACHA20_BLOCK_SIZE])
+ __u32 out[CHACHA20_BLOCK_WORDS])
{
unsigned long v, flags;
@@ -943,7 +943,7 @@
spin_unlock_irqrestore(&crng->lock, flags);
}
-static void extract_crng(__u8 out[CHACHA20_BLOCK_SIZE])
+static void extract_crng(__u32 out[CHACHA20_BLOCK_WORDS])
{
struct crng_state *crng = NULL;
@@ -961,7 +961,7 @@
* enough) to mutate the CRNG key to provide backtracking protection.
*/
static void _crng_backtrack_protect(struct crng_state *crng,
- __u8 tmp[CHACHA20_BLOCK_SIZE], int used)
+ __u32 tmp[CHACHA20_BLOCK_WORDS], int used)
{
unsigned long flags;
__u32 *s, *d;
@@ -973,14 +973,14 @@
used = 0;
}
spin_lock_irqsave(&crng->lock, flags);
- s = (__u32 *) &tmp[used];
+ s = &tmp[used / sizeof(__u32)];
d = &crng->state[4];
for (i=0; i < 8; i++)
*d++ ^= *s++;
spin_unlock_irqrestore(&crng->lock, flags);
}
-static void crng_backtrack_protect(__u8 tmp[CHACHA20_BLOCK_SIZE], int used)
+static void crng_backtrack_protect(__u32 tmp[CHACHA20_BLOCK_WORDS], int used)
{
struct crng_state *crng = NULL;
@@ -996,7 +996,7 @@
static ssize_t extract_crng_user(void __user *buf, size_t nbytes)
{
ssize_t ret = 0, i = CHACHA20_BLOCK_SIZE;
- __u8 tmp[CHACHA20_BLOCK_SIZE];
+ __u32 tmp[CHACHA20_BLOCK_WORDS];
int large_request = (nbytes > 256);
while (nbytes) {
@@ -1564,7 +1564,7 @@
*/
void get_random_bytes(void *buf, int nbytes)
{
- __u8 tmp[CHACHA20_BLOCK_SIZE];
+ __u32 tmp[CHACHA20_BLOCK_WORDS];
#if DEBUG_RANDOM_BOOT > 0
if (!crng_ready())
@@ -2132,7 +2132,7 @@
batch = &get_cpu_var(batched_entropy_long);
if (batch->position % ARRAY_SIZE(batch->entropy_long) == 0) {
- extract_crng((u8 *)batch->entropy_long);
+ extract_crng((__u32 *)batch->entropy_long);
batch->position = 0;
}
ret = batch->entropy_long[batch->position++];
@@ -2158,7 +2158,7 @@
batch = &get_cpu_var(batched_entropy_int);
if (batch->position % ARRAY_SIZE(batch->entropy_int) == 0) {
- extract_crng((u8 *)batch->entropy_int);
+ extract_crng((__u32 *)batch->entropy_int);
batch->position = 0;
}
ret = batch->entropy_int[batch->position++];
diff --git a/include/crypto/chacha20.h b/include/crypto/chacha20.h
index 20d20f68..254298b 100644
--- a/include/crypto/chacha20.h
+++ b/include/crypto/chacha20.h
@@ -11,12 +11,13 @@
#define CHACHA20_IV_SIZE 16
#define CHACHA20_KEY_SIZE 32
#define CHACHA20_BLOCK_SIZE 64
+#define CHACHA20_BLOCK_WORDS (CHACHA20_BLOCK_SIZE / sizeof(u32))
struct chacha20_ctx {
u32 key[8];
};
-void chacha20_block(u32 *state, void *stream);
+void chacha20_block(u32 *state, u32 *stream);
void crypto_chacha20_init(u32 *state, struct chacha20_ctx *ctx, u8 *iv);
int crypto_chacha20_setkey(struct crypto_tfm *tfm, const u8 *key,
unsigned int keysize);
diff --git a/lib/chacha20.c b/lib/chacha20.c
index 250ceed..29d3801 100644
--- a/lib/chacha20.c
+++ b/lib/chacha20.c
@@ -21,7 +21,7 @@
return (v << n) | (v >> (sizeof(v) * 8 - n));
}
-extern void chacha20_block(u32 *state, void *stream)
+void chacha20_block(u32 *state, u32 *stream)
{
u32 x[16], *out = stream;
int i;