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authorEric Biggers <ebiggers@google.com>2018-07-23 20:54:58 +0300
committerHerbert Xu <herbert@gondor.apana.org.au>2018-08-03 13:06:04 +0300
commit318abdfbe708aaaa652c79fb500e9bd60521f9dc (patch)
tree37e2e89d56b6d5e057ee515c50ade51e4406b3b2
parent0868def3e4100591e7a1fdbf3eed1439cc8f7ca3 (diff)
downloadlinux-318abdfbe708aaaa652c79fb500e9bd60521f9dc.tar.xz
crypto: ablkcipher - fix crash flushing dcache in error path
Like the skcipher_walk and blkcipher_walk cases: scatterwalk_done() is only meant to be called after a nonzero number of bytes have been processed, since scatterwalk_pagedone() will flush the dcache of the *previous* page. But in the error case of ablkcipher_walk_done(), e.g. if the input wasn't an integer number of blocks, scatterwalk_done() was actually called after advancing 0 bytes. This caused a crash ("BUG: unable to handle kernel paging request") during '!PageSlab(page)' on architectures like arm and arm64 that define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE, provided that the input was page-aligned as in that case walk->offset == 0. Fix it by reorganizing ablkcipher_walk_done() to skip the scatterwalk_advance() and scatterwalk_done() if an error has occurred. Reported-by: Liu Chao <liuchao741@huawei.com> Fixes: bf06099db18a ("crypto: skcipher - Add ablkcipher_walk interfaces") Cc: <stable@vger.kernel.org> # v2.6.35+ Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r--crypto/ablkcipher.c57
1 files changed, 26 insertions, 31 deletions
diff --git a/crypto/ablkcipher.c b/crypto/ablkcipher.c
index 1edb5000d783..8882e90e868e 100644
--- a/crypto/ablkcipher.c
+++ b/crypto/ablkcipher.c
@@ -71,11 +71,9 @@ static inline u8 *ablkcipher_get_spot(u8 *start, unsigned int len)
return max(start, end_page);
}
-static inline unsigned int ablkcipher_done_slow(struct ablkcipher_walk *walk,
- unsigned int bsize)
+static inline void ablkcipher_done_slow(struct ablkcipher_walk *walk,
+ unsigned int n)
{
- unsigned int n = bsize;
-
for (;;) {
unsigned int len_this_page = scatterwalk_pagelen(&walk->out);
@@ -87,17 +85,13 @@ static inline unsigned int ablkcipher_done_slow(struct ablkcipher_walk *walk,
n -= len_this_page;
scatterwalk_start(&walk->out, sg_next(walk->out.sg));
}
-
- return bsize;
}
-static inline unsigned int ablkcipher_done_fast(struct ablkcipher_walk *walk,
- unsigned int n)
+static inline void ablkcipher_done_fast(struct ablkcipher_walk *walk,
+ unsigned int n)
{
scatterwalk_advance(&walk->in, n);
scatterwalk_advance(&walk->out, n);
-
- return n;
}
static int ablkcipher_walk_next(struct ablkcipher_request *req,
@@ -107,39 +101,40 @@ int ablkcipher_walk_done(struct ablkcipher_request *req,
struct ablkcipher_walk *walk, int err)
{
struct crypto_tfm *tfm = req->base.tfm;
- 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 & ABLKCIPHER_WALK_SLOW)))
- n = ablkcipher_done_fast(walk, n);
- else if (WARN_ON(err)) {
- err = -EINVAL;
- goto err;
- } else
- n = ablkcipher_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 & ABLKCIPHER_WALK_SLOW))) {
+ ablkcipher_done_fast(walk, n);
+ } else {
+ if (WARN_ON(err)) {
+ /* unexpected case; didn't process all bytes */
+ err = -EINVAL;
+ goto finish;
+ }
+ ablkcipher_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(req->base.flags);
return ablkcipher_walk_next(req, walk);
}
-
+ err = 0;
+finish:
+ walk->nbytes = 0;
if (walk->iv != req->info)
memcpy(req->info, walk->iv, tfm->crt_ablkcipher.ivsize);
kfree(walk->iv_buffer);
-
return err;
}
EXPORT_SYMBOL_GPL(ablkcipher_walk_done);