From 421d82f5b3e75f94e31875e37d45cdf6a557c120 Mon Sep 17 00:00:00 2001 From: Nickolaus Woodruff Date: Wed, 26 Nov 2014 13:40:57 -0500 Subject: [PATCH] crypto: drbg - use memzero_explicit() for clearing sensitive data Compiler dead store optimization can sometimes remove final calls to memset() used to clear sensitive data at the end of a function. Replace trailing memset() calls with memzero_explicit() to preclude unwanted removal. Signed-off-by: Nickolaus Woodruff Signed-off-by: Herbert Xu --- crypto/drbg.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/crypto/drbg.c b/crypto/drbg.c index c90e3cf5967f..d748a1d0ca24 100644 --- a/crypto/drbg.c +++ b/crypto/drbg.c @@ -98,6 +98,7 @@ */ #include +#include /*************************************************************** * Backend cipher definitions available to DRBG @@ -497,9 +498,9 @@ static int drbg_ctr_df(struct drbg_state *drbg, ret = 0; out: - memset(iv, 0, drbg_blocklen(drbg)); - memset(temp, 0, drbg_statelen(drbg)); - memset(pad, 0, drbg_blocklen(drbg)); + memzero_explicit(iv, drbg_blocklen(drbg)); + memzero_explicit(temp, drbg_statelen(drbg)); + memzero_explicit(pad, drbg_blocklen(drbg)); return ret; } @@ -573,9 +574,9 @@ static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed, ret = 0; out: - memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg)); + memzero_explicit(temp, drbg_statelen(drbg) + drbg_blocklen(drbg)); if (2 != reseed) - memset(df_data, 0, drbg_statelen(drbg)); + memzero_explicit(df_data, drbg_statelen(drbg)); return ret; } @@ -633,7 +634,7 @@ static int drbg_ctr_generate(struct drbg_state *drbg, len = ret; out: - memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); + memzero_explicit(drbg->scratchpad, drbg_blocklen(drbg)); return len; } @@ -871,7 +872,7 @@ static int drbg_hash_df(struct drbg_state *drbg, } out: - memset(tmp, 0, drbg_blocklen(drbg)); + memzero_explicit(tmp, drbg_blocklen(drbg)); return ret; } @@ -915,7 +916,7 @@ static int drbg_hash_update(struct drbg_state *drbg, struct list_head *seed, ret = drbg_hash_df(drbg, drbg->C, drbg_statelen(drbg), &datalist2); out: - memset(drbg->scratchpad, 0, drbg_statelen(drbg)); + memzero_explicit(drbg->scratchpad, drbg_statelen(drbg)); return ret; } @@ -950,7 +951,7 @@ static int drbg_hash_process_addtl(struct drbg_state *drbg, drbg->scratchpad, drbg_blocklen(drbg)); out: - memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); + memzero_explicit(drbg->scratchpad, drbg_blocklen(drbg)); return ret; } @@ -997,7 +998,7 @@ static int drbg_hash_hashgen(struct drbg_state *drbg, } out: - memset(drbg->scratchpad, 0, + memzero_explicit(drbg->scratchpad, (drbg_statelen(drbg) + drbg_blocklen(drbg))); return len; } @@ -1046,7 +1047,7 @@ static int drbg_hash_generate(struct drbg_state *drbg, drbg_add_buf(drbg->V, drbg_statelen(drbg), u.req, 8); out: - memset(drbg->scratchpad, 0, drbg_blocklen(drbg)); + memzero_explicit(drbg->scratchpad, drbg_blocklen(drbg)); return len; } -- 2.34.1