From bed97f6469974aecf3db3874e2cfcf5ae4d14018 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Thu, 30 May 2019 10:50:39 -0700 Subject: [PATCH] crypto: ghash - fix unaligned memory access in ghash_setkey() commit 5c6bc4dfa515738149998bb0db2481a4fdead979 upstream. Changing ghash_mod_init() to be subsys_initcall made it start running before the alignment fault handler has been installed on ARM. In kernel builds where the keys in the ghash test vectors happened to be misaligned in the kernel image, this exposed the longstanding bug that ghash_setkey() is incorrectly casting the key buffer (which can have any alignment) to be128 for passing to gf128mul_init_4k_lle(). Fix this by memcpy()ing the key to a temporary buffer. Don't fix it by setting an alignmask on the algorithm instead because that would unnecessarily force alignment of the data too. Fixes: 2cdc6899a88e ("crypto: ghash - Add GHASH digest algorithm for GCM") Reported-by: Peter Robinson Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Tested-by: Peter Robinson Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- crypto/ghash-generic.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/crypto/ghash-generic.c b/crypto/ghash-generic.c index d9f192b953b2..591b52d3bdca 100644 --- a/crypto/ghash-generic.c +++ b/crypto/ghash-generic.c @@ -34,6 +34,7 @@ static int ghash_setkey(struct crypto_shash *tfm, const u8 *key, unsigned int keylen) { struct ghash_ctx *ctx = crypto_shash_ctx(tfm); + be128 k; if (keylen != GHASH_BLOCK_SIZE) { crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN); @@ -42,7 +43,12 @@ static int ghash_setkey(struct crypto_shash *tfm, if (ctx->gf128) gf128mul_free_4k(ctx->gf128); - ctx->gf128 = gf128mul_init_4k_lle((be128 *)key); + + BUILD_BUG_ON(sizeof(k) != GHASH_BLOCK_SIZE); + memcpy(&k, key, GHASH_BLOCK_SIZE); /* avoid violating alignment rules */ + ctx->gf128 = gf128mul_init_4k_lle(&k); + memzero_explicit(&k, GHASH_BLOCK_SIZE); + if (!ctx->gf128) return -ENOMEM;