diff options
| author | Herbert Xu <herbert@gondor.apana.org.au> | 2016-07-03 04:46:11 +0200 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2016-07-03 09:44:56 +0200 |
| commit | 27710b8ea3defcbd7d340dbd0423d911b4eb7c4f (patch) | |
| tree | 02e55d5dac1b26f47137b59ae51bc0fbab69e392 /crypto | |
| parent | crypto: sha3 - Add HMAC-SHA3 test modes and test vectors (diff) | |
| download | linux-27710b8ea3defcbd7d340dbd0423d911b4eb7c4f.tar.xz linux-27710b8ea3defcbd7d340dbd0423d911b4eb7c4f.zip | |
crypto: rsa-pkcs1pad - Fix regression from leading zeros
As the software RSA implementation now produces fixed-length
output, we need to eliminate leading zeros in the calling code
instead.
This patch does just that for pkcs1pad signature verification.
Fixes: 9b45b7bba3d2 ("crypto: rsa - Generate fixed-length output")
Reported-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/rsa-pkcs1pad.c | 38 |
1 files changed, 22 insertions, 16 deletions
diff --git a/crypto/rsa-pkcs1pad.c b/crypto/rsa-pkcs1pad.c index 8ccfdd7c926e..880d3db57a25 100644 --- a/crypto/rsa-pkcs1pad.c +++ b/crypto/rsa-pkcs1pad.c @@ -456,49 +456,55 @@ static int pkcs1pad_verify_complete(struct akcipher_request *req, int err) struct akcipher_instance *inst = akcipher_alg_instance(tfm); struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst); const struct rsa_asn1_template *digest_info = ictx->digest_info; + unsigned int dst_len; unsigned int pos; - - if (err == -EOVERFLOW) - /* Decrypted value had no leading 0 byte */ - err = -EINVAL; + u8 *out_buf; if (err) goto done; - if (req_ctx->child_req.dst_len != ctx->key_size - 1) { - err = -EINVAL; + err = -EINVAL; + dst_len = req_ctx->child_req.dst_len; + if (dst_len < ctx->key_size - 1) goto done; + + out_buf = req_ctx->out_buf; + if (dst_len == ctx->key_size) { + if (out_buf[0] != 0x00) + /* Decrypted value had no leading 0 byte */ + goto done; + + dst_len--; + out_buf++; } err = -EBADMSG; - if (req_ctx->out_buf[0] != 0x01) + if (out_buf[0] != 0x01) goto done; - for (pos = 1; pos < req_ctx->child_req.dst_len; pos++) - if (req_ctx->out_buf[pos] != 0xff) + for (pos = 1; pos < dst_len; pos++) + if (out_buf[pos] != 0xff) break; - if (pos < 9 || pos == req_ctx->child_req.dst_len || - req_ctx->out_buf[pos] != 0x00) + if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00) goto done; pos++; - if (memcmp(req_ctx->out_buf + pos, digest_info->data, - digest_info->size)) + if (memcmp(out_buf + pos, digest_info->data, digest_info->size)) goto done; pos += digest_info->size; err = 0; - if (req->dst_len < req_ctx->child_req.dst_len - pos) + if (req->dst_len < dst_len - pos) err = -EOVERFLOW; - req->dst_len = req_ctx->child_req.dst_len - pos; + req->dst_len = dst_len - pos; if (!err) sg_copy_from_buffer(req->dst, sg_nents_for_len(req->dst, req->dst_len), - req_ctx->out_buf + pos, req->dst_len); + out_buf + pos, req->dst_len); done: kzfree(req_ctx->out_buf); |