Message ID | 20200206114201.25438-1-Jason@zx2c4.com (mailing list archive) |
---|---|
State | Accepted |
Delegated to: | Herbert Xu |
Headers | show |
Series | [stable] crypto: chacha20poly1305 - prevent integer overflow on large input | expand |
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 >
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> > --- > lib/crypto/chacha20poly1305.c | 3 +++ > 1 file changed, 3 insertions(+) Patch applied. Thanks.
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;
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> --- lib/crypto/chacha20poly1305.c | 3 +++ 1 file changed, 3 insertions(+)