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author | Eric Biggers <ebiggers@google.com> | 2018-07-23 10:54:58 -0700 |
---|---|---|
committer | Herbert Xu <herbert@gondor.apana.org.au> | 2018-08-03 18:06:04 +0800 |
commit | 318abdfbe708aaaa652c79fb500e9bd60521f9dc (patch) | |
tree | 37e2e89d56b6d5e057ee515c50ade51e4406b3b2 | |
parent | 0868def3e4100591e7a1fdbf3eed1439cc8f7ca3 (diff) | |
download | linux-stable-318abdfbe708aaaa652c79fb500e9bd60521f9dc.tar.gz linux-stable-318abdfbe708aaaa652c79fb500e9bd60521f9dc.tar.bz2 linux-stable-318abdfbe708aaaa652c79fb500e9bd60521f9dc.zip |
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.c | 57 |
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); |