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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id f35-20020a17090a28a600b00203125b6394sm53549pjd.40.2022.09.26.17.40.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Sep 2022 17:40:35 -0700 (PDT) From: Kees Cook To: Ido Schimmel Cc: Kees Cook , Petr Machata , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH] mlxsw: core_acl_flex_actions: Split memcpy() of struct flow_action_cookie flexible array Date: Mon, 26 Sep 2022 17:40:33 -0700 Message-Id: <20220927004033.1942992-1-keescook@chromium.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1634; h=from:subject; bh=anKrQLY+XsXKgHz694GQioMoU17jgmFoTynuopZyaGg=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBjMkaBfu8qN5shW54b50aHf+icSE8mqDj2fL3Oe3rs UiET1fGJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYzJGgQAKCRCJcvTf3G3AJkJwD/ 4uuK+VZ1mJBwvloZTYwkWWvwMD6O3YJ7TlM8I3YOOzoU110PcLcBRFA7Fc/yXBhhfWyeu8zxZz4mG0 BJvV+bms9nxA+oed4ATwwaSmDBHEA+T+SNurvu3uC+aN5KYlnb1yE/jDO13fvSqQv0I803i+jEcyVO lk+W0UdsTTMivSv6LF80i6YZpfUokBfj1sRj02fhQCXLmxLE1YtiYyf/8kH2c6FM1nDHvTonWV+vyX bTTJeN2PG7tWse9aH2IJSIrCiRmQfLa9WzC2aYTNXaBvepHo+K65zWwJcVnVSn1jdOXD/ExTuFskWf pfdKMPEhjrf/aYNOYT8xk84SsDil50pYL+fpkUPj/qyU0qScRKPwwm5n82NvbbV5o79tn4oW8oqBu/ LGgLek3r0oxVr9ywDqwldNvEDtR3JMSTSyI/wcTWBtP1d1AZqNQHVsYFh3DJ17cDS2NXKYm6bBQkXx gLmYCl8Kp/LfWWxEJXHap6W8Lb1GXO/v1ccXCC3vmNU239OKe4vV2hpfYKLjY1u6KfpVBlo3VclLHV LxPrIANqJQby71uZk10OdGr8G0OgVSBTwGnRC6eIXC45o1pJwUpVXEgBILgskr8F5H0zPsMCtnfG+w KXZrR+CL6okF4VYg791WIUh1eRy9thQpt+y6zi663njUo/Pj39cmCR7+RQHQ== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org To work around a misbehavior of the compiler's ability to see into composite flexible array structs (as detailed in the coming memcpy() hardening series[1]), split the memcpy() of the header and the payload so no false positive run-time overflow warning will be generated. [1] https://lore.kernel.org/linux-hardening/20220901065914.1417829-2-keescook@chromium.org Cc: Ido Schimmel Cc: Petr Machata Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook Reviewed-by: Gustavo A. R. Silva Reviewed-by: Petr Machata --- drivers/net/ethernet/mellanox/mlxsw/core_acl_flex_actions.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlxsw/core_acl_flex_actions.c b/drivers/net/ethernet/mellanox/mlxsw/core_acl_flex_actions.c index 636db9a87457..9dfe7148199f 100644 --- a/drivers/net/ethernet/mellanox/mlxsw/core_acl_flex_actions.c +++ b/drivers/net/ethernet/mellanox/mlxsw/core_acl_flex_actions.c @@ -737,8 +737,9 @@ mlxsw_afa_cookie_create(struct mlxsw_afa *mlxsw_afa, if (!cookie) return ERR_PTR(-ENOMEM); refcount_set(&cookie->ref_count, 1); - memcpy(&cookie->fa_cookie, fa_cookie, - sizeof(*fa_cookie) + fa_cookie->cookie_len); + cookie->fa_cookie = *fa_cookie; + memcpy(cookie->fa_cookie.cookie, fa_cookie->cookie, + fa_cookie->cookie_len); err = rhashtable_insert_fast(&mlxsw_afa->cookie_ht, &cookie->ht_node, mlxsw_afa_cookie_ht_params);