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authorHerbert Xu <herbert@gondor.apana.org.au>2016-09-22 17:04:57 +0800
committerHerbert Xu <herbert@gondor.apana.org.au>2016-09-22 17:42:08 +0800
commit0cf43f509f72128196e23f5ade7e512a72152cc6 (patch)
tree093421f3aa73817b2d0f46fcd06cd9c56c849c94 /crypto/rsa-pkcs1pad.c
parent456bee986e0a372ad4beed5d3cedb3622633d9df (diff)
downloadlwn-0cf43f509f72128196e23f5ade7e512a72152cc6.tar.gz
lwn-0cf43f509f72128196e23f5ade7e512a72152cc6.zip
crypto: rsa-pkcs1pad - Handle leading zero for decryption
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 decryption while signature verification was fixed in an earlier patch. Fixes: 9b45b7bba3d2 ("crypto: rsa - Generate fixed-length output") Reported-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/rsa-pkcs1pad.c')
-rw-r--r--crypto/rsa-pkcs1pad.c41
1 files changed, 24 insertions, 17 deletions
diff --git a/crypto/rsa-pkcs1pad.c b/crypto/rsa-pkcs1pad.c
index 877019a6d3ea..8baab4307f7b 100644
--- a/crypto/rsa-pkcs1pad.c
+++ b/crypto/rsa-pkcs1pad.c
@@ -298,41 +298,48 @@ static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
+ 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++;
}
- if (req_ctx->out_buf[0] != 0x02) {
- err = -EINVAL;
+ if (out_buf[0] != 0x02)
goto done;
- }
- for (pos = 1; pos < req_ctx->child_req.dst_len; pos++)
- if (req_ctx->out_buf[pos] == 0x00)
+
+ for (pos = 1; pos < dst_len; pos++)
+ if (out_buf[pos] == 0x00)
break;
- if (pos < 9 || pos == req_ctx->child_req.dst_len) {
- err = -EINVAL;
+ if (pos < 9 || pos == dst_len)
goto done;
- }
pos++;
- if (req->dst_len < req_ctx->child_req.dst_len - pos)
+ err = 0;
+
+ 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);