[PATCH] NFC: nci: Bounds check struct nfc_target arrays

[PATCH] NFC: nci: Bounds check struct nfc_target arrays

[Kees Cook]

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")
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 net/nfc/nci/ntf.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/nfc/nci/ntf.c b/net/nfc/nci/ntf.c
index 282c51051dcc..994a0a1efb58 100644
--- 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);
-- 
2.34.1

Re: [PATCH] NFC: nci: Bounds check struct nfc_target arrays

[Krzysztof Kozlowski]

On 02/12/2022 22:44, Kees Cook wrote:
> 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")
> Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: netdev@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---


Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

Re: [PATCH] NFC: nci: Bounds check struct nfc_target arrays

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Fri,  2 Dec 2022 13:44:14 -0800 you wrote:
> 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.
> 
> [...]

Here is the summary with links:
  - NFC: nci: Bounds check struct nfc_target arrays
    https://git.kernel.org/netdev/net/c/e329e71013c9

You are awesome, thank you!
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