[PATCH net v3] nfc: pn533: Clear nfc_target before being used

[PATCH net v3] nfc: pn533: Clear nfc_target before being used

[Minsuk Kang]

Fix a slab-out-of-bounds read that occurs in nla_put() called from
nfc_genl_send_target() when target->sensb_res_len, which is duplicated
from an nfc_target in pn533, is too large as the nfc_target is not
properly initialized and retains garbage values. Clear nfc_targets with
memset() before they are used.

Found by a modified version of syzkaller.

BUG: KASAN: slab-out-of-bounds in nla_put
Call Trace:
 memcpy
 nla_put
 nfc_genl_dump_targets
 genl_lock_dumpit
 netlink_dump
 __netlink_dump_start
 genl_family_rcv_msg_dumpit
 genl_rcv_msg
 netlink_rcv_skb
 genl_rcv
 netlink_unicast
 netlink_sendmsg
 sock_sendmsg
 ____sys_sendmsg
 ___sys_sendmsg
 __sys_sendmsg
 do_syscall_64

Fixes: 673088fb42d0 ("NFC: pn533: Send ATR_REQ directly for active device detection")
Fixes: 361f3cb7f9cf ("NFC: DEP link hook implementation for pn533")
Signed-off-by: Minsuk Kang <linuxlovemin@yonsei.ac.kr>
---
v2->v3:
  Remove an inappropriate tag

v1->v2:
  Clear another nfc_target in pn533_in_dep_link_up_complete()
  Fix the commit message

 drivers/nfc/pn533/pn533.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/nfc/pn533/pn533.c b/drivers/nfc/pn533/pn533.c
index d9f6367b9993..f0cac1900552 100644
--- a/drivers/nfc/pn533/pn533.c
+++ b/drivers/nfc/pn533/pn533.c
@@ -1295,6 +1295,8 @@ static int pn533_poll_dep_complete(struct pn533 *dev, void *arg,
 	if (IS_ERR(resp))
 		return PTR_ERR(resp);
 
+	memset(&nfc_target, 0, sizeof(struct nfc_target));
+
 	rsp = (struct pn533_cmd_jump_dep_response *)resp->data;
 
 	rc = rsp->status & PN533_CMD_RET_MASK;
@@ -1926,6 +1928,8 @@ static int pn533_in_dep_link_up_complete(struct pn533 *dev, void *arg,
 
 		dev_dbg(dev->dev, "Creating new target\n");
 
+		memset(&nfc_target, 0, sizeof(struct nfc_target));
+
 		nfc_target.supported_protocols = NFC_PROTO_NFC_DEP_MASK;
 		nfc_target.nfcid1_len = 10;
 		memcpy(nfc_target.nfcid1, rsp->nfcid3t, nfc_target.nfcid1_len);
-- 
2.25.1

Re: [PATCH net v3] nfc: pn533: Clear nfc_target before being used

[Krzysztof Kozlowski]

On 14/12/2022 02:51, Minsuk Kang wrote:
> Fix a slab-out-of-bounds read that occurs in nla_put() called from
> nfc_genl_send_target() when target->sensb_res_len, which is duplicated
> from an nfc_target in pn533, is too large as the nfc_target is not
> properly initialized and retains garbage values. Clear nfc_targets with
> memset() before they are used.
> 
> Found by a modified version of syzkaller.
> 
> BUG: KASAN: slab-out-of-bounds in nla_put
> Call Trace:
>  memcpy
>  nla_put
>  nfc_genl_dump_targets
>  genl_lock_dumpit
>  netlink_dump
>  __netlink_dump_start
>  genl_family_rcv_msg_dumpit
>  genl_rcv_msg
>  netlink_rcv_skb
>  genl_rcv
>  netlink_unicast
>  netlink_sendmsg
>  sock_sendmsg
>  ____sys_sendmsg
>  ___sys_sendmsg
>  __sys_sendmsg
>  do_syscall_64
> 
> Fixes: 673088fb42d0 ("NFC: pn533: Send ATR_REQ directly for active device detection")
> Fixes: 361f3cb7f9cf ("NFC: DEP link hook implementation for pn533")
> Signed-off-by: Minsuk Kang <linuxlovemin@yonsei.ac.kr>
> ---
> v2->v3:
>   Remove an inappropriate tag


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

Best regards,
Krzysztof

Re: [PATCH net v3] nfc: pn533: Clear nfc_target before being used

[patchwork-bot+netdevbpf]

Hello:

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

On Wed, 14 Dec 2022 10:51:39 +0900 you wrote:
> Fix a slab-out-of-bounds read that occurs in nla_put() called from
> nfc_genl_send_target() when target->sensb_res_len, which is duplicated
> from an nfc_target in pn533, is too large as the nfc_target is not
> properly initialized and retains garbage values. Clear nfc_targets with
> memset() before they are used.
> 
> Found by a modified version of syzkaller.
> 
> [...]

Here is the summary with links:
  - [net,v3] nfc: pn533: Clear nfc_target before being used
    https://git.kernel.org/netdev/net/c/9f28157778ed

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html