Re: cryptoapi highmem bug

[Christophe Saout <christophe@saout.de>]

On Wed, Feb 25, 2004 at 11:50:27AM -0800, Andrew Morton wrote:

> Or maybe it's sufficient for crypt() to pass a simple boolean down to the
> prfn() callout which says "this is in-place encryption".

Yes, this works. As usual I was simply thinking too complicated. ;)

It looks like this now. It's on top of Jean-Luc's patch. Jean-Luc, can
update your patch and use this one instead? It's much simpler this way
and it keeps the whole voodoo in cipher.c.

diff -ur linux.orig/crypto/cipher.c linux/crypto/cipher.c
--- linux.orig/crypto/cipher.c	2004-02-25 17:26:06.000000000 +0100
+++ linux/crypto/cipher.c	2004-02-25 22:11:03.000000000 +0100
@@ -26,7 +26,7 @@
 
 typedef void (cryptfn_t)(void *, u8 *, const u8 *);
 typedef void (procfn_t)(struct crypto_tfm *, u8 *,
-                        u8*, cryptfn_t, int enc, void *);
+                        u8*, cryptfn_t, int enc, void *, int);
 
 static inline void xor_64(u8 *a, const u8 *b)
 {
@@ -81,7 +81,9 @@
 
 		scatterwalk_copychunks(src_p, &walk_in, bsize, 0);
 
-		prfn(tfm, dst_p, src_p, crfn, enc, info);
+		prfn(tfm, dst_p, src_p, crfn, enc, info,
+		     scatterwalk_samebuf(&walk_in, &walk_out,
+					 src_p, dst_p));
 
 		scatterwalk_done(&walk_in, 0, nbytes);
 
@@ -185,8 +187,8 @@
 }
 #endif /* CONFIG_CRYPTO_OMAC */
 
-static void cbc_process(struct crypto_tfm *tfm,
-                        u8 *dst, u8 *src, cryptfn_t fn, int enc, void *info)
+static void cbc_process(struct crypto_tfm *tfm, u8 *dst, u8 *src,
+			cryptfn_t fn, int enc, void *info, int in_place)
 {
 	u8 *iv = info;
 	
@@ -202,9 +204,8 @@
 		fn(crypto_tfm_ctx(tfm), dst, iv);
 		memcpy(iv, dst, crypto_tfm_alg_blocksize(tfm));
 	} else {
-		const int need_stack = (src == dst);
-		u8 stack[need_stack ? crypto_tfm_alg_blocksize(tfm) : 0];
-		u8 *buf = need_stack ? stack : dst;
+		u8 stack[in_place ? crypto_tfm_alg_blocksize(tfm) : 0];
+		u8 *buf = in_place ? stack : dst;
 		
 		fn(crypto_tfm_ctx(tfm), buf, src);
 		tfm->crt_u.cipher.cit_xor_block(buf, iv);
@@ -214,13 +215,12 @@
 	}
 }
 
-static void ctr_process(struct crypto_tfm *tfm,
-                        u8 *dst, u8 *src, cryptfn_t fn, int enc, void *info)
+static void ctr_process(struct crypto_tfm *tfm, u8 *dst, u8 *src,
+			cryptfn_t fn, int enc, void *info, int in_place)
 {
 	u8 *iv = info;
-	const int need_stack = (src == dst);
-	u8 stack[need_stack ? crypto_tfm_alg_blocksize(tfm) : 0];
-	u8 *buf = need_stack ? stack : dst;
+	u8 stack[in_place ? crypto_tfm_alg_blocksize(tfm) : 0];
+	u8 *buf = in_place ? stack : dst;
 	int i;
 
 	/* Null encryption */
@@ -255,7 +255,7 @@
 
 
 static void ecb_process(struct crypto_tfm *tfm, u8 *dst, u8 *src,
-                        cryptfn_t fn, int enc, void *info)
+			cryptfn_t fn, int enc, void *info, int in_place)
 {
 	/* we can use dst as scratch space since we overwrite it later */
 	omac_update(tfm, dst, src);
diff -ur linux.orig/crypto/scatterwalk.h linux/crypto/scatterwalk.h
--- linux.orig/crypto/scatterwalk.h	2004-02-25 17:26:06.000000000 +0100
+++ linux/crypto/scatterwalk.h	2004-02-25 22:10:15.000000000 +0100
@@ -38,6 +38,14 @@
 	return sg + 1;
 }
 
+static inline int scatterwalk_samebuf(struct scatter_walk *walk_in,
+				      struct scatter_walk *walk_out,
+				      void *src_p, void *dst_p)
+{
+	return walk_in->page == walk_out->page &&
+	       walk_in->data == src_p && walk_out->data == dst_p;
+}
+
 void *scatterwalk_whichbuf(struct scatter_walk *walk, unsigned int nbytes, void *scratch);
 void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
 int scatterwalk_copychunks(void *buf, struct scatter_walk *walk, size_t nbytes, int out);