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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 <nickolauswoodruff@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Nickolaus Woodruff 2014-11-26 13:40:57 -05:00 committed by Herbert Xu
parent 0653a7cf6f
commit 421d82f5b3
1 changed files with 12 additions and 11 deletions
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23
crypto/drbg.c
View File

@ -98,6 +98,7 @@
*/
#include <crypto/drbg.h>
#include <linux/string.h>
/***************************************************************
* 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;
}