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authorKees Cook <keescook@chromium.org>2022-09-23 21:08:35 -0700
committerJakub Kicinski <kuba@kernel.org>2022-09-27 07:45:18 -0700
commitde4feb4e3d61026f81b15ada6f64deaf40125ffc (patch)
tree592cc0d923b1c86654465d4b0bcf8ee0e6ca92fe /net
parent454b20e19322e6a9375cbaad68fff3c93bd27716 (diff)
NFC: hci: Split memcpy() of struct hcp_message flexible array
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. This split already existed for the "firstfrag" case, so just generalize the logic further. [1] https://lore.kernel.org/linux-hardening/20220901065914.1417829-2-keescook@chromium.org/ Cc: Eric Dumazet <edumazet@google.com> Cc: Paolo Abeni <pabeni@redhat.com> Reported-by: "Gustavo A. R. Silva" <gustavoars@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Link: https://lore.kernel.org/r/20220924040835.3364912-1-keescook@chromium.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/nfc/hci/hcp.c12
1 files changed, 5 insertions, 7 deletions
diff --git a/net/nfc/hci/hcp.c b/net/nfc/hci/hcp.c
index 05c60988f59a..4902f5064098 100644
--- a/net/nfc/hci/hcp.c
+++ b/net/nfc/hci/hcp.c
@@ -73,14 +73,12 @@ int nfc_hci_hcp_message_tx(struct nfc_hci_dev *hdev, u8 pipe,
if (firstfrag) {
firstfrag = false;
packet->message.header = HCP_HEADER(type, instruction);
- if (ptr) {
- memcpy(packet->message.data, ptr,
- data_link_len - 1);
- ptr += data_link_len - 1;
- }
} else {
- memcpy(&packet->message, ptr, data_link_len);
- ptr += data_link_len;
+ packet->message.header = *ptr++;
+ }
+ if (ptr) {
+ memcpy(packet->message.data, ptr, data_link_len - 1);
+ ptr += data_link_len - 1;
}
/* This is the last fragment, set the cb bit */