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 <nickolauswoodruff@xxxxxxxxx> --- crypto/drbg.c | 22 +++++++++++----------- include/crypto/drbg.h | 1 + 2 files changed, 12 insertions(+), 11 deletions(-) diff --git a/crypto/drbg.c b/crypto/drbg.c index 54cfd48..c6258ca 100644 --- a/crypto/drbg.c +++ b/crypto/drbg.c @@ -522,9 +522,9 @@ 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; } @@ -599,9 +599,9 @@ 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; } @@ -660,7 +660,7 @@ 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; } @@ -848,7 +848,7 @@ static int drbg_hash_df(struct drbg_state *drbg, } out: - memset(tmp, 0, drbg_blocklen(drbg)); + memzero_explicit(tmp, drbg_blocklen(drbg)); return ret; } @@ -892,7 +892,7 @@ 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; } @@ -927,7 +927,7 @@ 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; } @@ -975,7 +975,7 @@ 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; } @@ -1024,7 +1024,7 @@ 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; } diff --git a/include/crypto/drbg.h b/include/crypto/drbg.h index 5186f75..13471a2 100644 --- a/include/crypto/drbg.h +++ b/include/crypto/drbg.h @@ -45,6 +45,7 @@ #include <crypto/hash.h> #include <linux/module.h> #include <linux/crypto.h> +#include <linux/string.h> #include <linux/slab.h> #include <crypto/internal/rng.h> #include <crypto/rng.h> -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
