target/linux/generic/backport-5.4/080-wireguard-0051-crypto-chacha20poly1305-prevent-integer-overflow-on-.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: "Jason A. Donenfeld" <Jason@zx2c4.com>
   3 Date: Thu, 6 Feb 2020 12:42:01 +0100
   4 Subject: [PATCH] crypto: chacha20poly1305 - prevent integer overflow on large
   5  input
   6
   7 commit c9cc0517bba9f0213f1e55172feceb99e5512daf upstream.
   8
   9 This code assigns src_len (size_t) to sl (int), which causes problems
  10 when src_len is very large. Probably nobody in the kernel should be
  11 passing this much data to chacha20poly1305 all in one go anyway, so I
  12 don't think we need to change the algorithm or introduce larger types
  13 or anything. But we should at least error out early in this case and
  14 print a warning so that we get reports if this does happen and can look
  15 into why anybody is possibly passing it that much data or if they're
  16 accidently passing -1 or similar.
  17
  18 Fixes: d95312a3ccc0 ("crypto: lib/chacha20poly1305 - reimplement crypt_from_sg() routine")
  19 Cc: Ard Biesheuvel <ardb@kernel.org>
  20 Cc: stable@vger.kernel.org # 5.5+
  21 Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
  22 Acked-by: Ard Biesheuvel <ardb@kernel.org>
  23 Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
  24 Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
  25 ---
  26  lib/crypto/chacha20poly1305.c | 3 +++
  27  1 file changed, 3 insertions(+)
  28
  29 --- a/lib/crypto/chacha20poly1305.c
  30 +++ b/lib/crypto/chacha20poly1305.c
  31 @@ -235,6 +235,9 @@ bool chacha20poly1305_crypt_sg_inplace(s
  32                 __le64 lens[2];
  33         } b __aligned(16);
  34
  35 +       if (WARN_ON(src_len > INT_MAX))
  36 +               return false;
  37 +
  38         chacha_load_key(b.k, key);
  39
  40         b.iv[0] = 0;