NFC: nci: Bounds check struct nfc_target arrays

While running under CONFIG_FORTIFY_SOURCE=y, syzkaller reported:

  memcpy: detected field-spanning write (size 129) of single field "target->sensf_res" at net/nfc/nci/ntf.c:260 (size 18)

This appears to be a legitimate lack of bounds checking in
nci_add_new_protocol(). Add the missing checks.

Reported-by: syzbot+210e196cef4711b65139@syzkaller.appspotmail.com
Link: https://lore.kernel.org/lkml/0000000000001c590f05ee7b3ff4@google.com
Fixes: 019c4fbaa790 ("NFC: Add NCI multiple targets support")
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221202214410.never.693-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/nfc/nci/ntf.c b/net/nfc/nci/ntf.c
index 282c510..994a0a1 100644 (file)
--- a/net/nfc/nci/ntf.c
+++ b/net/nfc/nci/ntf.c
@@ -240,6 +240,8 @@ static int nci_add_new_protocol(struct nci_dev *ndev,
                target->sens_res = nfca_poll->sens_res;
                target->sel_res = nfca_poll->sel_res;
                target->nfcid1_len = nfca_poll->nfcid1_len;
+               if (target->nfcid1_len > ARRAY_SIZE(target->nfcid1))
+                       return -EPROTO;
                if (target->nfcid1_len > 0) {
                        memcpy(target->nfcid1, nfca_poll->nfcid1,
                               target->nfcid1_len);
@@ -248,6 +250,8 @@ static int nci_add_new_protocol(struct nci_dev *ndev,
                nfcb_poll = (struct rf_tech_specific_params_nfcb_poll *)params;
 
                target->sensb_res_len = nfcb_poll->sensb_res_len;
+               if (target->sensb_res_len > ARRAY_SIZE(target->sensb_res))
+                       return -EPROTO;
                if (target->sensb_res_len > 0) {
                        memcpy(target->sensb_res, nfcb_poll->sensb_res,
                               target->sensb_res_len);
@@ -256,6 +260,8 @@ static int nci_add_new_protocol(struct nci_dev *ndev,
                nfcf_poll = (struct rf_tech_specific_params_nfcf_poll *)params;
 
                target->sensf_res_len = nfcf_poll->sensf_res_len;
+               if (target->sensf_res_len > ARRAY_SIZE(target->sensf_res))
+                       return -EPROTO;
                if (target->sensf_res_len > 0) {
                        memcpy(target->sensf_res, nfcf_poll->sensf_res,
                               target->sensf_res_len);