Messages in this thread | | | Date | Fri, 22 Dec 2017 19:34:16 +1100 | From | Herbert Xu <> | Subject | Re: [PATCH] crypto: chacha20poly1305 - validate the digest size |
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On Mon, Dec 11, 2017 at 12:15:17PM -0800, Eric Biggers wrote: > From: Eric Biggers <ebiggers@google.com> > > If the rfc7539 template was instantiated with a hash algorithm with > digest size larger than 16 bytes (POLY1305_DIGEST_SIZE), then the digest > overran the 'tag' buffer in 'struct chachapoly_req_ctx', corrupting the > subsequent memory, including 'cryptlen'. This caused a crash during > crypto_skcipher_decrypt(). > > Fix it by, when instantiating the template, requiring that the > underlying hash algorithm has the digest size expected for Poly1305. > > Reproducer: > > #include <linux/if_alg.h> > #include <sys/socket.h> > #include <unistd.h> > > int main() > { > int algfd, reqfd; > struct sockaddr_alg addr = { > .salg_type = "aead", > .salg_name = "rfc7539(chacha20,sha256)", > }; > unsigned char buf[32] = { 0 }; > > algfd = socket(AF_ALG, SOCK_SEQPACKET, 0); > bind(algfd, (void *)&addr, sizeof(addr)); > setsockopt(algfd, SOL_ALG, ALG_SET_KEY, buf, sizeof(buf)); > reqfd = accept(algfd, 0, 0); > write(reqfd, buf, 16); > read(reqfd, buf, 16); > } > > Reported-by: syzbot <syzkaller@googlegroups.com> > Fixes: 71ebc4d1b27d ("crypto: chacha20poly1305 - Add a ChaCha20-Poly1305 AEAD construction, RFC7539") > Cc: <stable@vger.kernel.org> # v4.2+ > Signed-off-by: Eric Biggers <ebiggers@google.com>
Patch applied. Thanks. -- Email: Herbert Xu <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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