diff --git a/target/linux/generic/backport-5.4/080-wireguard-0051-crypto-chacha20poly1305-prevent-integer-overflow-on-.patch b/target/linux/generic/backport-5.4/080-wireguard-0051-crypto-chacha20poly1305-prevent-integer-overflow-on-.patch
new file mode 100644
index 0000000..1ed49e5
--- /dev/null
+++ b/target/linux/generic/backport-5.4/080-wireguard-0051-crypto-chacha20poly1305-prevent-integer-overflow-on-.patch
@@ -0,0 +1,40 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: "Jason A. Donenfeld" <Jason@zx2c4.com>
+Date: Thu, 6 Feb 2020 12:42:01 +0100
+Subject: [PATCH] crypto: chacha20poly1305 - prevent integer overflow on large
+ input
+
+commit c9cc0517bba9f0213f1e55172feceb99e5512daf upstream.
+
+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>
+Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
+Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
+---
+ lib/crypto/chacha20poly1305.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+--- a/lib/crypto/chacha20poly1305.c
++++ b/lib/crypto/chacha20poly1305.c
+@@ -235,6 +235,9 @@ bool chacha20poly1305_crypt_sg_inplace(s
+ 		__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;