From ee97dc7db4cbda33e4241c2d85b42d1835bc8a35 Mon Sep 17 00:00:00 2001 From: Harald Freudenberger Date: Wed, 22 Jan 2014 13:01:33 +0100 Subject: [PATCH] crypto: s390 - fix des and des3_ede ctr concurrency issue In s390 des and 3des ctr mode there is one preallocated page used to speed up the en/decryption. This page is not protected against concurrent usage and thus there is a potential of data corruption with multiple threads. The fix introduces locking/unlocking the ctr page and a slower fallback solution at concurrency situations. Cc: stable@vger.kernel.org Signed-off-by: Harald Freudenberger Signed-off-by: Herbert Xu --- arch/s390/crypto/des_s390.c | 69 ++++++++++++++++++++++++++----------- 1 file changed, 48 insertions(+), 21 deletions(-) diff --git a/arch/s390/crypto/des_s390.c b/arch/s390/crypto/des_s390.c index 82a0a2ad2494..0a5aac8a9412 100644 --- a/arch/s390/crypto/des_s390.c +++ b/arch/s390/crypto/des_s390.c @@ -25,6 +25,7 @@ #define DES3_KEY_SIZE (3 * DES_KEY_SIZE) static u8 *ctrblk; +static DEFINE_SPINLOCK(ctrblk_lock); struct s390_des_ctx { u8 iv[DES_BLOCK_SIZE]; @@ -368,54 +369,80 @@ static struct crypto_alg cbc_des3_alg = { } }; +static unsigned int __ctrblk_init(u8 *ctrptr, unsigned int nbytes) +{ + unsigned int i, n; + + /* align to block size, max. PAGE_SIZE */ + n = (nbytes > PAGE_SIZE) ? PAGE_SIZE : nbytes & ~(DES_BLOCK_SIZE - 1); + for (i = DES_BLOCK_SIZE; i < n; i += DES_BLOCK_SIZE) { + memcpy(ctrptr + i, ctrptr + i - DES_BLOCK_SIZE, DES_BLOCK_SIZE); + crypto_inc(ctrptr + i, DES_BLOCK_SIZE); + } + return n; +} + static int ctr_desall_crypt(struct blkcipher_desc *desc, long func, - struct s390_des_ctx *ctx, struct blkcipher_walk *walk) + struct s390_des_ctx *ctx, + struct blkcipher_walk *walk) { int ret = blkcipher_walk_virt_block(desc, walk, DES_BLOCK_SIZE); - unsigned int i, n, nbytes; - u8 buf[DES_BLOCK_SIZE]; - u8 *out, *in; + unsigned int n, nbytes; + u8 buf[DES_BLOCK_SIZE], ctrbuf[DES_BLOCK_SIZE]; + u8 *out, *in, *ctrptr = ctrbuf; + + if (!walk->nbytes) + return ret; - memcpy(ctrblk, walk->iv, DES_BLOCK_SIZE); + if (spin_trylock(&ctrblk_lock)) + ctrptr = ctrblk; + + memcpy(ctrptr, walk->iv, DES_BLOCK_SIZE); while ((nbytes = walk->nbytes) >= DES_BLOCK_SIZE) { out = walk->dst.virt.addr; in = walk->src.virt.addr; while (nbytes >= DES_BLOCK_SIZE) { - /* align to block size, max. PAGE_SIZE */ - n = (nbytes > PAGE_SIZE) ? PAGE_SIZE : - nbytes & ~(DES_BLOCK_SIZE - 1); - for (i = DES_BLOCK_SIZE; i < n; i += DES_BLOCK_SIZE) { - memcpy(ctrblk + i, ctrblk + i - DES_BLOCK_SIZE, - DES_BLOCK_SIZE); - crypto_inc(ctrblk + i, DES_BLOCK_SIZE); - } - ret = crypt_s390_kmctr(func, ctx->key, out, in, n, ctrblk); - if (ret < 0 || ret != n) + if (ctrptr == ctrblk) + n = __ctrblk_init(ctrptr, nbytes); + else + n = DES_BLOCK_SIZE; + ret = crypt_s390_kmctr(func, ctx->key, out, in, + n, ctrptr); + if (ret < 0 || ret != n) { + if (ctrptr == ctrblk) + spin_unlock(&ctrblk_lock); return -EIO; + } if (n > DES_BLOCK_SIZE) - memcpy(ctrblk, ctrblk + n - DES_BLOCK_SIZE, + memcpy(ctrptr, ctrptr + n - DES_BLOCK_SIZE, DES_BLOCK_SIZE); - crypto_inc(ctrblk, DES_BLOCK_SIZE); + crypto_inc(ctrptr, DES_BLOCK_SIZE); out += n; in += n; nbytes -= n; } ret = blkcipher_walk_done(desc, walk, nbytes); } - + if (ctrptr == ctrblk) { + if (nbytes) + memcpy(ctrbuf, ctrptr, DES_BLOCK_SIZE); + else + memcpy(walk->iv, ctrptr, DES_BLOCK_SIZE); + spin_unlock(&ctrblk_lock); + } /* final block may be < DES_BLOCK_SIZE, copy only nbytes */ if (nbytes) { out = walk->dst.virt.addr; in = walk->src.virt.addr; ret = crypt_s390_kmctr(func, ctx->key, buf, in, - DES_BLOCK_SIZE, ctrblk); + DES_BLOCK_SIZE, ctrbuf); if (ret < 0 || ret != DES_BLOCK_SIZE) return -EIO; memcpy(out, buf, nbytes); - crypto_inc(ctrblk, DES_BLOCK_SIZE); + crypto_inc(ctrbuf, DES_BLOCK_SIZE); ret = blkcipher_walk_done(desc, walk, 0); + memcpy(walk->iv, ctrbuf, DES_BLOCK_SIZE); } - memcpy(walk->iv, ctrblk, DES_BLOCK_SIZE); return ret; } -- 2.39.5