Commit abdb460d authored by Andy Polyakov's avatar Andy Polyakov
Browse files

evp/bio_enc.c: perform enc_read operation without using overlapping buffers. 



Reviewed-by: default avatarStephen Henson <steve@openssl.org>
parent 382bb0b2

crypto/evp/bio_enc.c

+27 −9
Original line number Diff line number Diff line
@@ -40,7 +40,7 @@ typedef struct enc_struct { 
     * buf is larger than ENC_BLOCK_SIZE because EVP_DecryptUpdate can return

     * up to a block more data than is presented to it

     */

    char buf[ENC_BLOCK_SIZE + BUF_OFFSET + 2];

    unsigned char buf[ENC_BLOCK_SIZE + BUF_OFFSET + 2];

} BIO_ENC_CTX;



static const BIO_METHOD methods_enc = {
@@ -136,32 +136,50 @@ static int enc_read(BIO *b, char *out, int outl) 
     */



    while (outl > 0) {

        int buf_len;



        if (ctx->cont <= 0)

            break;



        buf_len = outl + EVP_MAX_BLOCK_LENGTH - 1;

        buf_len -= buf_len % EVP_MAX_BLOCK_LENGTH;

        if (buf_len > ENC_BLOCK_SIZE) {

            buf_len = ENC_BLOCK_SIZE;

        }



        /*

         * read in at IV offset, read the EVP_Cipher documentation about why

         */

        i = BIO_read(next, &(ctx->buf[BUF_OFFSET]), ENC_BLOCK_SIZE);

        i = BIO_read(next, &(ctx->buf[BUF_OFFSET]), buf_len);



        if (i <= 0) {

            /* Should be continue next time we are called? */

            if (!BIO_should_retry(next)) {

                ctx->cont = i;

                i = EVP_CipherFinal_ex(ctx->cipher,

                                       (unsigned char *)ctx->buf,

                                       &(ctx->buf_len));

                                       ctx->buf, &(ctx->buf_len));

                ctx->ok = i;

                ctx->buf_off = 0;

            } else {

                ret = (ret == 0) ? i : ret;

                break;

            }

        } else if (outl >= EVP_MAX_BLOCK_LENGTH) {

            if (!EVP_CipherUpdate(ctx->cipher,

                                  (unsigned char *)out, &buf_len,

                                  &(ctx->buf[BUF_OFFSET]), i)) {

                BIO_clear_retry_flags(b);

                return 0;

            }

            ret += buf_len;

            outl -= buf_len;

            out += buf_len;



            continue;

        } else {

            if (!EVP_CipherUpdate(ctx->cipher,

                                  (unsigned char *)ctx->buf, &ctx->buf_len,

                                  (unsigned char *)&(ctx->buf[BUF_OFFSET]),

                                  i)) {

                                  ctx->buf, &ctx->buf_len,

                                  &(ctx->buf[BUF_OFFSET]), i)) {

                BIO_clear_retry_flags(b);

                ctx->ok = 0;

                return 0;
@@ -228,8 +246,8 @@ static int enc_write(BIO *b, const char *in, int inl) 
    while (inl > 0) {

        n = (inl > ENC_BLOCK_SIZE) ? ENC_BLOCK_SIZE : inl;

        if (!EVP_CipherUpdate(ctx->cipher,

                              (unsigned char *)ctx->buf, &ctx->buf_len,

                              (unsigned char *)in, n)) {

                              ctx->buf, &ctx->buf_len,

                              (const unsigned char *)in, n)) {

            BIO_clear_retry_flags(b);

            ctx->ok = 0;

            return 0;