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[198.0.35.241]) by smtp.gmail.com with ESMTPSA id p11-20020a170902a40b00b0019460ac7c6asm12547885plq.283.2023.02.15.14.41.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Feb 2023 14:41:16 -0800 (PST) From: Kees Cook To: Arend van Spriel Cc: Kees Cook , Ard Biesheuvel , Franky Lin , Hante Meuleman , Kalle Valo , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Johannes Berg , "Jason A. Donenfeld" , Greg Kroah-Hartman , "Darrick J. Wong" , Colin Ian King , Brian Henriquez , linux-wireless@vger.kernel.org, brcm80211-dev-list.pdl@broadcom.com, SHA-cyfmac-dev-list@infineon.com, netdev@vger.kernel.org, Jason Gunthorpe , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH] wifi: brcmfmac: p2p: Introduce generic flexible array frame member Date: Wed, 15 Feb 2023 14:41:14 -0800 Message-Id: <20230215224110.never.022-kees@kernel.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2984; h=from:subject:message-id; bh=NH05WGlz+NfU8MmAO7fhDCoD/bk5xcg8PiXevXOGYSQ=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBj7V+KSkepxl6m0w6HQmTbuhMT6gFMTrKHHEn1r560 zilCZCGJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCY+1figAKCRCJcvTf3G3AJlg6D/ 9qMIaHwoHnLx1HJ4KX7Nv5fk/N7aOg/N9My3M1Wz1uzob6c6m1wNf8ByQ233hu0dvdVGkcuou6PDGZ XqeqxOOKQJ+sJcE+md+OPHeYzuQl5dZ+DgPE623iyEDeCxSrxBWgN62zF2o1OPrxWYIpT+ggxyItoq h2Nve+50UFQV1kk5Lco1P5dkNmPNUnbxZj3OFO03dgb379EkMrRy5/e1I7PaPV5QqLKCfwFbQ0Ak56 +3XQvas7yA0vXG5FmXOg4LOliAB8mNpxbSt2BBKUt34yUw8KH4nAogrqtk+VqKfHR+NvXHN9Bppy8T EaMNN0FnfYujqSpVcvlnrrj8yzaINe+I019+ct+FO76MniG5GL51c9bwnGl7jkdl4HcfygL9ZQTKs2 U0GqvMxtzZNTxVTaxgVxG3HK5Ejk0mmsEZMsggjrLlv1nN8W6tylgLay3VCJi3OpwoJsHRKPNN8RzT Mxd85Tah3an4b7Y9SNsKN0kwivhsWHVbuSsZXoVkwkYeciFom7QfqXu5TkHPnOvXUE1bw1YMgHAnyc HgyzyE59M1BvyYRX9LFFr8EHhHyV4pzQKjKxmLWEmPzvZqn96itCaD5FGQYAoj3sO/9CeslfAEigth i8O+/02BUNLmAExMGZFGPTCc2m2cDuo/7EGQ3FapqrmMPbQoFpFsFpK97+jA== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org Silence run-time memcpy() false positive warning when processing management frames: memcpy: detected field-spanning write (size 27) of single field "&mgmt_frame->u" at drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c:1469 (size 26) Due to this (soon to be fixed) GCC bug[1], FORTIFY_SOURCE (via __builtin_dynamic_object_size) doesn't recognize that the union may end with a flexible array, and returns "26" (the fixed size of the union), rather than the remaining size of the allocation. Add an explicit flexible array member and set it as the destination here, so that we get the correct coverage for the memcpy(). [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101832 Reported-by: Ard Biesheuvel Cc: Arend van Spriel Cc: Franky Lin Cc: Hante Meuleman Cc: Kalle Valo Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Johannes Berg Cc: "Jason A. Donenfeld" Cc: Greg Kroah-Hartman Cc: "Darrick J. Wong" Cc: Colin Ian King Cc: Brian Henriquez Cc: linux-wireless@vger.kernel.org Cc: brcm80211-dev-list.pdl@broadcom.com Cc: SHA-cyfmac-dev-list@infineon.com Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook Reviewed-by: Linus Walleij --- drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c | 4 ++-- include/linux/ieee80211.h | 1 + 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c index e975d10e6009..4d0db7107e65 100644 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c @@ -1466,8 +1466,8 @@ int brcmf_p2p_notify_action_frame_rx(struct brcmf_if *ifp, ETH_ALEN); memcpy(mgmt_frame->sa, e->addr, ETH_ALEN); mgmt_frame->frame_control = cpu_to_le16(IEEE80211_STYPE_ACTION); - memcpy(&mgmt_frame->u, frame, mgmt_frame_len); - mgmt_frame_len += offsetof(struct ieee80211_mgmt, u); + memcpy(mgmt_frame->u.frame, frame, mgmt_frame_len); + mgmt_frame_len += offsetof(struct ieee80211_mgmt, u.frame); freq = ieee80211_channel_to_frequency(ch.control_ch_num, ch.band == BRCMU_CHAN_BAND_2G ? diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h index 80d6308dea06..990d204d918a 100644 --- a/include/linux/ieee80211.h +++ b/include/linux/ieee80211.h @@ -1356,6 +1356,7 @@ struct ieee80211_mgmt { } __packed wnm_timing_msr; } u; } __packed action; + DECLARE_FLEX_ARRAY(u8, frame); /* Generic frame contents. */ } u; } __packed __aligned(2);