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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id p6sm4473754pjh.24.2021.06.16.21.27.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Jun 2021 21:27:11 -0700 (PDT) From: Kees Cook To: netdev@vger.kernel.org Cc: Kees Cook , Johannes Berg , "David S. Miller" , Jakub Kicinski , linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH] mac80211: Recast pointer for trailing memcpy() Date: Wed, 16 Jun 2021 21:27:09 -0700 Message-Id: <20210617042709.2170111-1-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Patch-Hashes: v=1; h=sha256; g=a59972a95d22e6cba17e8ca1ef339d3a3ef1b4e5; i=P4B4b65qJuhqVi5i2irgu0AhoblNfL65fECGIen2RpA=; m=ye9VNM2/KkSGCD7iU041Afv+zNGB2BR/2/Lf1/HGmmk=; p=jmhDm1u21oAA6abJCLcWjlq9egIRuBdVv23WaQ1b954= X-Patch-Sig: m=pgp; i=keescook@chromium.org; s=0x0x8972F4DFDC6DC026; b=iQIzBAABCgAdFiEEpcP2jyKd1g9yPm4TiXL039xtwCYFAmDKzxwACgkQiXL039xtwCZKsQ/+KRk qClgQaevJdpMV/HrC1/U+leuhMDzRHQ+71fiVOPofuqUOQVTtWE+ofVrBg5T6/rY7R3yAsr+M6jIl NJ5qwODjOmqe2eIHOtMdAd4junJjRi6O+8K7pH2Y8x7WLob4RubcXcogaPRTWlrcYGQiWAD14hyv2 mOkbE6mK0UWHeNnACpdecukYVYk5r3MTX0P/OlUO/FwEfnEhrM+DaXP/HWV9EbIQNqbEwsDmcTKY8 VtIggri22AUecFKn4TZKZJ7BIr1R7gMabDODg5vQRdnavOQ2LTaYprz+LO34lEaAsxfPU2onkBVet QIQBQS0Ti8XB+PcQuFsuIdTbu/qxP0yTqvwDq+C1bcSDkzsRMkDu/jGJfbA79rAt16c380/hh9eqP T78RVtzSJBOX+FpOA+/cQR5oZPQzKJpOjAIbdfbyazFb/+qaVakoDq6X0lmtF4MQgo0hrbhJg83Nc nQ4xKK6c6WN1Sno8eGF/JZl5GNKNNdolU2hEmyBJc46P/1CWCOqkhxON0XWPJWJVtqvea1i+WUYDn 7e9lU3+RyC8m/7yaBWVHyolrF+zityHQGiJKD0C6HZmACMw9nA/v5du3fLhtjD68HH8PhAdM8IEjt caIQX7Cm+K9rpWZB/2N/l5dXOIMPjx8g9R8DJtnr2znfH5CD4wW1DFjnlLen/Cco= Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memcpy(), memmove(), and memset(), avoid intentionally writing across neighboring array fields. Give memcpy() a specific source pointer type so it can correctly calculate the bounds of the copy. Signed-off-by: Kees Cook --- net/mac80211/rx.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index af0ef456eb0f..cb141bb788a8 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -559,6 +559,8 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local, if (status->encoding == RX_ENC_HE && status->flag & RX_FLAG_RADIOTAP_HE) { + struct ieee80211_radiotap_he *he_ptr; + #define HE_PREP(f, val) le16_encode_bits(val, IEEE80211_RADIOTAP_HE_##f) if (status->enc_flags & RX_ENC_FLAG_STBC_MASK) { @@ -626,18 +628,22 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local, while ((pos - (u8 *)rthdr) & 1) pos++; rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_HE); - memcpy(pos, &he, sizeof(he)); - pos += sizeof(he); + he_ptr = (void *)pos; + memcpy(he_ptr, &he, sizeof(he)); + pos += sizeof(*he_ptr); } if (status->encoding == RX_ENC_HE && status->flag & RX_FLAG_RADIOTAP_HE_MU) { + struct ieee80211_radiotap_he_mu *he_mu_ptr; + /* ensure 2 byte alignment */ while ((pos - (u8 *)rthdr) & 1) pos++; rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_HE_MU); - memcpy(pos, &he_mu, sizeof(he_mu)); - pos += sizeof(he_mu); + he_mu_ptr = (void *)pos; + memcpy(he_mu_ptr, &he_mu, sizeof(he_mu)); + pos += sizeof(*he_mu_ptr); } if (status->flag & RX_FLAG_NO_PSDU) { @@ -647,12 +653,14 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local, } if (status->flag & RX_FLAG_RADIOTAP_LSIG) { + struct ieee80211_radiotap_lsig *lsig_ptr; /* ensure 2 byte alignment */ while ((pos - (u8 *)rthdr) & 1) pos++; rthdr->it_present |= cpu_to_le32(1 << IEEE80211_RADIOTAP_LSIG); - memcpy(pos, &lsig, sizeof(lsig)); - pos += sizeof(lsig); + lsig_ptr = (void *)pos; + memcpy(lsig_ptr, &lsig, sizeof(lsig)); + pos += sizeof(*lsig_ptr); } for_each_set_bit(chain, &chains, IEEE80211_MAX_CHAINS) { -- 2.25.1