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crypto: skcipher - Unmap pages after an external error 

skcipher_walk_done may be called with an error by internal or
external callers.  For those internal callers we shouldn't unmap
pages but for external callers we must unmap any pages that are
in use.

This patch distinguishes between the two cases by checking whether
walk->nbytes is zero or not.  For internal callers, we now set
walk->nbytes to zero prior to the call.  For external callers,
walk->nbytes has always been non-zero (as zero is used to indicate
the termination of a walk).

Reported-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Fixes: 5cde0af2a9 ("[CRYPTO] cipher: Added block cipher type")
Cc: <stable@vger.kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Herbert Xu 2019-09-06 13:13:06 +10:00
parent 7b865ec15e
commit 0ba3c026e6
1 changed files with 23 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
crypto/skcipher.c
View File

@ -90,7 +90,7 @@ static inline u8 *skcipher_get_spot(u8 *start, unsigned int len)
return max(start, end_page); return max(start, end_page);
} }
static void skcipher_done_slow(struct skcipher_walk *walk, unsigned int bsize) static int skcipher_done_slow(struct skcipher_walk *walk, unsigned int bsize)
{ {
u8 *addr; u8 *addr;
@ -98,19 +98,21 @@ static void skcipher_done_slow(struct skcipher_walk *walk, unsigned int bsize)
addr = skcipher_get_spot(addr, bsize); addr = skcipher_get_spot(addr, bsize);
scatterwalk_copychunks(addr, &walk->out, bsize, scatterwalk_copychunks(addr, &walk->out, bsize,
(walk->flags & SKCIPHER_WALK_PHYS) ? 2 : 1); (walk->flags & SKCIPHER_WALK_PHYS) ? 2 : 1);
return 0;
} }
int skcipher_walk_done(struct skcipher_walk *walk, int err) int skcipher_walk_done(struct skcipher_walk *walk, int err)
{ {
unsigned int n; /* bytes processed */ unsigned int n = walk->nbytes;
bool more; unsigned int nbytes = 0;
if (unlikely(err < 0)) if (!n)
goto finish; goto finish;
n = walk->nbytes - err; if (likely(err >= 0)) {
walk->total -= n; n -= err;
more = (walk->total != 0); nbytes = walk->total - n;
}
if (likely(!(walk->flags & (SKCIPHER_WALK_PHYS | if (likely(!(walk->flags & (SKCIPHER_WALK_PHYS |
SKCIPHER_WALK_SLOW | SKCIPHER_WALK_SLOW |
@ -126,7 +128,7 @@ unmap_src:
memcpy(walk->dst.virt.addr, walk->page, n); memcpy(walk->dst.virt.addr, walk->page, n);
skcipher_unmap_dst(walk); skcipher_unmap_dst(walk);
} else if (unlikely(walk->flags & SKCIPHER_WALK_SLOW)) { } else if (unlikely(walk->flags & SKCIPHER_WALK_SLOW)) {
if (err) { if (err > 0) {
/* /*
* Didn't process all bytes. Either the algorithm is * Didn't process all bytes. Either the algorithm is
* broken, or this was the last step and it turned out * broken, or this was the last step and it turned out
@ -134,27 +136,29 @@ unmap_src:
* the algorithm requires it. * the algorithm requires it.
*/ */
err = -EINVAL; err = -EINVAL;
goto finish; nbytes = 0;
} } else
skcipher_done_slow(walk, n); n = skcipher_done_slow(walk, n);
goto already_advanced;
} }
if (err > 0)
err = 0;
walk->total = nbytes;
walk->nbytes = 0;
scatterwalk_advance(&walk->in, n); scatterwalk_advance(&walk->in, n);
scatterwalk_advance(&walk->out, n); scatterwalk_advance(&walk->out, n);
already_advanced: scatterwalk_done(&walk->in, 0, nbytes);
scatterwalk_done(&walk->in, 0, more); scatterwalk_done(&walk->out, 1, nbytes);
scatterwalk_done(&walk->out, 1, more);
if (more) { if (nbytes) {
crypto_yield(walk->flags & SKCIPHER_WALK_SLEEP ? crypto_yield(walk->flags & SKCIPHER_WALK_SLEEP ?
CRYPTO_TFM_REQ_MAY_SLEEP : 0); CRYPTO_TFM_REQ_MAY_SLEEP : 0);
return skcipher_walk_next(walk); return skcipher_walk_next(walk);
} }
err = 0;
finish:
walk->nbytes = 0;
finish:
/* Short-circuit for the common/fast path. */ /* Short-circuit for the common/fast path. */
if (!((unsigned long)walk->buffer | (unsigned long)walk->page)) if (!((unsigned long)walk->buffer | (unsigned long)walk->page))
goto out; goto out;