On Thu, 6 Feb 2020 at 11:42, Jason A. Donenfeld Jason@zx2c4.com wrote:

This code assigns src_len (size_t) to sl (int), which causes problems when src_len is very large. Probably nobody in the kernel should be passing this much data to chacha20poly1305 all in one go anyway, so I don't think we need to change the algorithm or introduce larger types or anything. But we should at least error out early in this case and print a warning so that we get reports if this does happen and can look into why anybody is possibly passing it that much data or if they're accidently passing -1 or similar.

Fixes: d95312a3ccc0 ("crypto: lib/chacha20poly1305 - reimplement crypt_from_sg() routine") Cc: Ard Biesheuvel ardb@kernel.org Cc: stable@vger.kernel.org # 5.5+ Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com

Acked-by: Ard Biesheuvel ardb@kernel.org

---

lib/crypto/chacha20poly1305.c | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/lib/crypto/chacha20poly1305.c b/lib/crypto/chacha20poly1305.c index 6d83cafebc69..ad0699ce702f 100644 --- a/lib/crypto/chacha20poly1305.c +++ b/lib/crypto/chacha20poly1305.c @@ -235,6 +235,9 @@ bool chacha20poly1305_crypt_sg_inplace(struct scatterlist *src, __le64 lens[2]; } b __aligned(16);

•   if (WARN_ON(src_len > INT_MAX))
  

•           return false;
  

•   chacha_load_key(b.k, key);
  
    b.iv[0] = 0;
  

-- 2.25.0