From: Herbert Xu herbert@gondor.apana.org.au
commit 0ba3c026e685573bd3534c17e27da7c505ac99c4 upstream.
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: 5cde0af2a982 ("[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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- crypto/skcipher.c | 42 +++++++++++++++++++++++------------------- 1 file changed, 23 insertions(+), 19 deletions(-)
--- a/crypto/skcipher.c +++ b/crypto/skcipher.c @@ -95,7 +95,7 @@ static inline u8 *skcipher_get_spot(u8 * 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;
@@ -103,19 +103,21 @@ static void skcipher_done_slow(struct sk addr = skcipher_get_spot(addr, bsize); scatterwalk_copychunks(addr, &walk->out, bsize, (walk->flags & SKCIPHER_WALK_PHYS) ? 2 : 1); + return 0; }
int skcipher_walk_done(struct skcipher_walk *walk, int err) { - unsigned int n; /* bytes processed */ - bool more; + unsigned int n = walk->nbytes; + unsigned int nbytes = 0;
- if (unlikely(err < 0)) + if (!n) goto finish;
- n = walk->nbytes - err; - walk->total -= n; - more = (walk->total != 0); + if (likely(err >= 0)) { + n -= err; + nbytes = walk->total - n; + }
if (likely(!(walk->flags & (SKCIPHER_WALK_PHYS | SKCIPHER_WALK_SLOW | @@ -131,7 +133,7 @@ unmap_src: memcpy(walk->dst.virt.addr, walk->page, n); skcipher_unmap_dst(walk); } else if (unlikely(walk->flags & SKCIPHER_WALK_SLOW)) { - if (err) { + if (err > 0) { /* * Didn't process all bytes. Either the algorithm is * broken, or this was the last step and it turned out @@ -139,27 +141,29 @@ unmap_src: * the algorithm requires it. */ err = -EINVAL; - goto finish; - } - skcipher_done_slow(walk, n); - goto already_advanced; + nbytes = 0; + } else + n = skcipher_done_slow(walk, n); }
+ if (err > 0) + err = 0; + + walk->total = nbytes; + walk->nbytes = 0; + scatterwalk_advance(&walk->in, n); scatterwalk_advance(&walk->out, n); -already_advanced: - scatterwalk_done(&walk->in, 0, more); - scatterwalk_done(&walk->out, 1, more); + scatterwalk_done(&walk->in, 0, nbytes); + scatterwalk_done(&walk->out, 1, nbytes);
- if (more) { + if (nbytes) { crypto_yield(walk->flags & SKCIPHER_WALK_SLEEP ? CRYPTO_TFM_REQ_MAY_SLEEP : 0); return skcipher_walk_next(walk); } - err = 0; -finish: - walk->nbytes = 0;
+finish: /* Short-circuit for the common/fast path. */ if (!((unsigned long)walk->buffer | (unsigned long)walk->page)) goto out;