From: Eric Biggers ebiggers@google.com
mainline inclusion from mainline-v5.18-rc1 commit d3481accd974541e6a5d6a1fb588924a3519c36e category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6ETWH CVE: NA
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RSA PKCS#1 v1.5 signatures are required to be the same length as the RSA key size. RFC8017 specifically requires the verifier to check this (https://datatracker.ietf.org/doc/html/rfc8017#section-8.2.2).
Commit a49de377e051 ("crypto: Add hash param to pkcs1pad") changed the kernel to allow longer signatures, but didn't explain this part of the change; it seems to be unrelated to the rest of the commit.
Revert this change, since it doesn't appear to be correct.
We can be pretty sure that no one is relying on overly-long signatures (which would have to be front-padded with zeroes) being supported, given that they would have been broken since commit c7381b012872 ("crypto: akcipher - new verify API for public key algorithms").
Fixes: a49de377e051 ("crypto: Add hash param to pkcs1pad") Cc: stable@vger.kernel.org # v4.6+ Cc: Tadeusz Struk tadeusz.struk@linaro.org Suggested-by: Vitaly Chikunov vt@altlinux.org Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Conflicts: crypto/rsa-pkcs1pad.c Signed-off-by: GUO Zihua guozihua@huawei.com Reviewed-by: yiyang yiyang13@huawei.com Reviewed-by: Wang Weiyang wangweiyang2@huawei.com Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com --- crypto/rsa-pkcs1pad.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/crypto/rsa-pkcs1pad.c b/crypto/rsa-pkcs1pad.c index ab2e74e23a7d..48bd07e22a1d 100644 --- a/crypto/rsa-pkcs1pad.c +++ b/crypto/rsa-pkcs1pad.c @@ -528,7 +528,7 @@ static int pkcs1pad_verify(struct akcipher_request *req) struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req); int err;
- if (!ctx->key_size || req->src_len < ctx->key_size) + if (!ctx->key_size || req->src_len != ctx->key_size) return -EINVAL;
req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);