tree b536a86e8992c9f45a39827c3ce54605f46b9ba7
parent 8e7d7ee1ae13027df7353ebedf71b998617a3469
author Gilles Peskine <Gilles.Peskine@arm.com> 1622539376 +0200
committer Gilles Peskine <Gilles.Peskine@arm.com> 1622545414 +0200

Fix null pointer arithmetic in error case

When mbedtls_nist_kw_wrap was called with output=NULL and out_size=0, it
performed arithmetic on the null pointer before detecting that the output
buffer is too small and returning an error code. This was unlikely to have
consequences on real-world hardware today, but it is undefined behavior and
UBSan with Clang 10 flagged it. So fix it (fix #4025).

Fix a similar-looking pattern in unwrap, though I haven't verified that it's
reachable there.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>