crypto: blkcipher - fix crash flushing dcache in error path

[mirror_ubuntu-bionic-kernel.git] / crypto / blkcipher.c

diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c
index a832426820e8ba5e912324153cea821083cd2b6a..d84c6920ada9fe0b814df033b066edcb1e06e22a 100644 (file)
--- a/crypto/blkcipher.c
+++ b/crypto/blkcipher.c
@@ -1,6 +1,6 @@
 /*
  * Block chaining cipher operations.
- * 
+ *
  * Generic encrypt/decrypt wrapper for ciphers, handles operations across
  * multiple page boundaries by using temporary blocks.  In user context,
  * the kernel is given a chance to schedule us once per page.
@@ -9,7 +9,7 @@
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the Free
- * Software Foundation; either version 2 of the License, or (at your option) 
+ * Software Foundation; either version 2 of the License, or (at your option)
  * any later version.
  *
  */
@@ -25,6 +25,7 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/cryptouser.h>
+#include <linux/compiler.h>
 #include <net/netlink.h>
 
 #include "internal.h"
@@ -70,19 +71,18 @@ static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len)
        return max(start, end_page);
 }
 
-static inline unsigned int blkcipher_done_slow(struct blkcipher_walk *walk,
-                                              unsigned int bsize)
+static inline void blkcipher_done_slow(struct blkcipher_walk *walk,
+                                      unsigned int bsize)
 {
        u8 *addr;
 
        addr = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
        addr = blkcipher_get_spot(addr, bsize);
        scatterwalk_copychunks(addr, &walk->out, bsize, 1);
-       return bsize;
 }
 
-static inline unsigned int blkcipher_done_fast(struct blkcipher_walk *walk,
-                                              unsigned int n)
+static inline void blkcipher_done_fast(struct blkcipher_walk *walk,
+                                      unsigned int n)
 {
        if (walk->flags & BLKCIPHER_WALK_COPY) {
                blkcipher_map_dst(walk);
@@ -96,49 +96,48 @@ static inline unsigned int blkcipher_done_fast(struct blkcipher_walk *walk,
 
        scatterwalk_advance(&walk->in, n);
        scatterwalk_advance(&walk->out, n);
-
-       return n;
 }
 
 int blkcipher_walk_done(struct blkcipher_desc *desc,
                        struct blkcipher_walk *walk, int err)
 {
-       unsigned int nbytes = 0;
+       unsigned int n; /* bytes processed */
+       bool more;
 
-       if (likely(err >= 0)) {
-               unsigned int n = walk->nbytes - err;
+       if (unlikely(err < 0))
+               goto finish;
 
-               if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW)))
-                       n = blkcipher_done_fast(walk, n);
-               else if (WARN_ON(err)) {
-                       err = -EINVAL;
-                       goto err;
-               } else
-                       n = blkcipher_done_slow(walk, n);
+       n = walk->nbytes - err;
+       walk->total -= n;
+       more = (walk->total != 0);
 
-               nbytes = walk->total - n;
-               err = 0;
+       if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW))) {
+               blkcipher_done_fast(walk, n);
+       } else {
+               if (WARN_ON(err)) {
+                       /* unexpected case; didn't process all bytes */
+                       err = -EINVAL;
+                       goto finish;
+               }
+               blkcipher_done_slow(walk, n);
        }
 
-       scatterwalk_done(&walk->in, 0, nbytes);
-       scatterwalk_done(&walk->out, 1, nbytes);
-
-err:
-       walk->total = nbytes;
-       walk->nbytes = nbytes;
+       scatterwalk_done(&walk->in, 0, more);
+       scatterwalk_done(&walk->out, 1, more);
 
-       if (nbytes) {
+       if (more) {
                crypto_yield(desc->flags);
                return blkcipher_walk_next(desc, walk);
        }
-
+       err = 0;
+finish:
+       walk->nbytes = 0;
        if (walk->iv != desc->info)
                memcpy(desc->info, walk->iv, walk->ivsize);
        if (walk->buffer != walk->page)
                kfree(walk->buffer);
        if (walk->page)
                free_page((unsigned long)walk->page);
-
        return err;
 }
 EXPORT_SYMBOL_GPL(blkcipher_walk_done);
@@ -534,7 +533,7 @@ static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 #endif
 
 static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
-       __attribute__ ((unused));
+       __maybe_unused;
 static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 {
        seq_printf(m, "type         : blkcipher\n");