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authorEric Biggers <ebiggers@google.com>2022-01-18 16:13:04 -0800
committerHerbert Xu <herbert@gondor.apana.org.au>2022-01-31 11:21:44 +1100
commitd3481accd974541e6a5d6a1fb588924a3519c36e (patch)
treed4d2e189b93a4784d9162fba6974c3d17ef296d9 /crypto
parente316f7179be22912281ce6331d96d7c121fb2b17 (diff)
downloadlinux-d3481accd974541e6a5d6a1fb588924a3519c36e.tar.bz2
crypto: rsa-pkcs1pad - restore signature length check
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>
Diffstat (limited to 'crypto')
-rw-r--r--crypto/rsa-pkcs1pad.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/crypto/rsa-pkcs1pad.c b/crypto/rsa-pkcs1pad.c
index 7b223adebabf..6b556ddeb3a0 100644
--- a/crypto/rsa-pkcs1pad.c
+++ b/crypto/rsa-pkcs1pad.c
@@ -538,7 +538,7 @@ static int pkcs1pad_verify(struct akcipher_request *req)
if (WARN_ON(req->dst) ||
WARN_ON(!req->dst_len) ||
- !ctx->key_size || req->src_len < ctx->key_size)
+ !ctx->key_size || req->src_len != ctx->key_size)
return -EINVAL;
req_ctx->out_buf = kmalloc(ctx->key_size + req->dst_len, GFP_KERNEL);