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crypto: ansi_prng - Use just a BH lock

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The current code uses a mix of sping_lock() & spin_lock_irqsave(). This can
lead to deadlock with the correct timming & cprng_get_random() + cprng_reset()
sequence.
I've converted them to bottom half locks since all three user grab just a BH
lock so this runs probably in softirq :)

Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Sebastian Andrzej Siewior 2009-07-03 12:09:41 +08:00 committed by Herbert Xu
parent a68f6610d4
commit ed94070058
1 changed files with 4 additions and 5 deletions
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9
crypto/ansi_cprng.c
View file

@ -187,7 +187,6 @@ static int _get_more_prng_bytes(struct prng_context *ctx)
/* Our exported functions */
static int get_prng_bytes(char *buf, size_t nbytes, struct prng_context *ctx)
{
unsigned long flags;
unsigned char *ptr = buf;
unsigned int byte_count = (unsigned int)nbytes;
int err;
@ -196,7 +195,7 @@ static int get_prng_bytes(char *buf, size_t nbytes, struct prng_context *ctx)
if (nbytes < 0)
return -EINVAL;
spin_lock_irqsave(&ctx->prng_lock, flags);
spin_lock_bh(&ctx->prng_lock);
err = -EINVAL;
if (ctx->flags & PRNG_NEED_RESET)
@ -268,7 +267,7 @@ empty_rbuf:
goto remainder;
done:
spin_unlock_irqrestore(&ctx->prng_lock, flags);
spin_unlock_bh(&ctx->prng_lock);
dbgprint(KERN_CRIT "returning %d from get_prng_bytes in context %p\n",
err, ctx);
return err;
@ -287,7 +286,7 @@ static int reset_prng_context(struct prng_context *ctx,
int rc = -EINVAL;
unsigned char *prng_key;
spin_lock(&ctx->prng_lock);
spin_lock_bh(&ctx->prng_lock);
ctx->flags |= PRNG_NEED_RESET;
prng_key = (key != NULL) ? key : (unsigned char *)DEFAULT_PRNG_KEY;
@ -332,7 +331,7 @@ static int reset_prng_context(struct prng_context *ctx,
rc = 0;
ctx->flags &= ~PRNG_NEED_RESET;
out:
spin_unlock(&ctx->prng_lock);
spin_unlock_bh(&ctx->prng_lock);
return rc;