[CRYPTO] all: Check for usage in hard IRQ context

Using blkcipher/hash crypto operations in hard IRQ context can lead
to random memory corruption due to the reuse of kmap_atomic slots.
Since crypto operations were never meant to be used in hard IRQ
contexts, this patch checks for such usage and returns an error
before kmap_atomic is performed.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 4 insertions, 0 deletions

diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c
index 6e93004f2181..cbb4c4e5c229 100644
--- a/crypto/blkcipher.c
+++ b/crypto/blkcipher.c
@@ -16,6 +16,7 @@
 
 #include <linux/crypto.h>
 #include <linux/errno.h>
+#include <linux/hardirq.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/scatterlist.h>
@@ -313,6 +314,9 @@ static int blkcipher_walk_first(struct blkcipher_desc *desc,
         struct crypto_blkcipher *tfm = desc->tfm;
         unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
 
+        if (WARN_ON_ONCE(in_irq()))
+                return -EDEADLK;
+
         walk->nbytes = walk->total;
         if (unlikely(!walk->total))
                 return 0;