On Sat, Jun 21, 2014 at 02:26:29PM +0200, Stephan Mueller wrote:
> The handling of additional input data / personalization string data may
> be subject to a NULL pointer deference for the CTR DRBG. The
> caller-provided data may be NULL which must be caught by the DRBG.
>
> Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx>
> Signed-off-by: Stephan Mueller <smueller@xxxxxxxxxx>
> ---
> crypto/drbg.c | 23 +++++++++++++----------
> 1 file changed, 13 insertions(+), 10 deletions(-)
>
> diff --git a/crypto/drbg.c b/crypto/drbg.c
> index faaa2ce..8e7c302 100644
> --- a/crypto/drbg.c
> +++ b/crypto/drbg.c
> @@ -513,17 +513,20 @@ static int drbg_ctr_df(struct drbg_state *drbg,
> drbg_string_fill(&S2, L_N, sizeof(L_N));
> drbg_string_fill(&S4, pad, padlen);
> S1.next = &S2;
> - S2.next = addtl;
>
> - /*
> - * splice in addtl between S2 and S4 -- we place S4 at the end of the
> - * input data chain
> - */
> - tempstr = addtl;
> - for (; NULL != tempstr; tempstr = tempstr->next)
> - if (NULL == tempstr->next)
> - break;
> - tempstr->next = &S4;
> + if (NULL == addtl) {
> + S2.next = &S4;
> + } else {
> + /*
> + * splice in addtl between S2 and S4 -- we place S4 at the end
> + * of the input data chain
> + */
> + S2.next = addtl;
> + tempstr = addtl;
> + while (tempstr->next)
> + tempstr = tempstr->next;
> + tempstr->next = &S4;
You've still got exactly the same NULL dereference.
--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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