[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, 17 insertions, 4 deletions

diff --git a/crypto/xcbc.c b/crypto/xcbc.c
index 9347eb6bcf69..317e9f08fc04 100644
--- a/crypto/xcbc.c
+++ b/crypto/xcbc.c
@@ -21,6 +21,7 @@
 
 #include <linux/crypto.h>
 #include <linux/err.h>
+#include <linux/hardirq.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/rtnetlink.h>
@@ -108,9 +109,9 @@ static int crypto_xcbc_digest_init(struct hash_desc *pdesc)
         return 0;
 }
 
-static int crypto_xcbc_digest_update(struct hash_desc *pdesc,
-                                     struct scatterlist *sg,
-                                     unsigned int nbytes)
+static int crypto_xcbc_digest_update2(struct hash_desc *pdesc,
+                                      struct scatterlist *sg,
+                                      unsigned int nbytes)
 {
         struct crypto_hash *parent = pdesc->tfm;
         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
@@ -183,6 +184,15 @@ static int crypto_xcbc_digest_update(struct hash_desc *pdesc,
         return 0;
 }
 
+static int crypto_xcbc_digest_update(struct hash_desc *pdesc,
+                                     struct scatterlist *sg,
+                                     unsigned int nbytes)
+{
+        if (WARN_ON_ONCE(in_irq()))
+                return -EDEADLK;
+        return crypto_xcbc_digest_update2(pdesc, sg, nbytes);
+}
+
 static int crypto_xcbc_digest_final(struct hash_desc *pdesc, u8 *out)
 {
         struct crypto_hash *parent = pdesc->tfm;
@@ -234,8 +244,11 @@ static int crypto_xcbc_digest_final(struct hash_desc *pdesc, u8 *out)
 static int crypto_xcbc_digest(struct hash_desc *pdesc,
                   struct scatterlist *sg, unsigned int nbytes, u8 *out)
 {
+        if (WARN_ON_ONCE(in_irq()))
+                return -EDEADLK;
+
         crypto_xcbc_digest_init(pdesc);
-        crypto_xcbc_digest_update(pdesc, sg, nbytes);
+        crypto_xcbc_digest_update2(pdesc, sg, nbytes);
         return crypto_xcbc_digest_final(pdesc, out);
 }