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Groups > linux.kernel > #1649454 > unrolled thread

[PATCH] nfc: Ensure presence of required attributes in the activate_target netlink handler

Started byMateusz Jurczyk <mjurczyk@google.com>
First post2017-05-24 12:50 +0200
Last post2017-05-24 19:10 +0200
Articles 2 — 2 participants

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  [PATCH] nfc: Ensure presence of required attributes in the activate_target netlink handler Mateusz Jurczyk <mjurczyk@google.com> - 2017-05-24 12:50 +0200
    Re: [PATCH] nfc: Ensure presence of required attributes in the  activate_target netlink handler Kees Cook <keescook@google.com> - 2017-05-24 19:10 +0200

#1649454 — [PATCH] nfc: Ensure presence of required attributes in the activate_target netlink handler

FromMateusz Jurczyk <mjurczyk@google.com>
Date2017-05-24 12:50 +0200
Subject[PATCH] nfc: Ensure presence of required attributes in the activate_target netlink handler
Message-ID<tKC1A-1db-13@gated-at.bofh.it>
Check that the NFC_ATTR_TARGET_INDEX and NFC_ATTR_PROTOCOLS attributes (in
addition to NFC_ATTR_DEVICE_INDEX) are provided by the netlink client
prior to accessing them. This prevents potential unhandled NULL pointer
dereference exceptions which can be triggered by malicious user-mode
programs, if they omit one or both of these attributes.

Signed-off-by: Mateusz Jurczyk <mjurczyk@google.com>
---
 net/nfc/netlink.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
index 6b0850e63e09..b251fb936a27 100644
--- a/net/nfc/netlink.c
+++ b/net/nfc/netlink.c
@@ -907,7 +907,9 @@ static int nfc_genl_activate_target(struct sk_buff *skb, struct genl_info *info)
 	u32 device_idx, target_idx, protocol;
 	int rc;
 
-	if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
+	if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
+	    !info->attrs[NFC_ATTR_TARGET_INDEX] ||
+	    !info->attrs[NFC_ATTR_PROTOCOLS])
 		return -EINVAL;
 
 	device_idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
-- 
2.13.0.219.gdb65acc882-goog

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#1649769 — Re: [PATCH] nfc: Ensure presence of required attributes in the activate_target netlink handler

FromKees Cook <keescook@google.com>
Date2017-05-24 19:10 +0200
SubjectRe: [PATCH] nfc: Ensure presence of required attributes in the activate_target netlink handler
Message-ID<tKHXj-58r-1@gated-at.bofh.it>
In reply to#1649454
On Wed, May 24, 2017 at 3:42 AM, Mateusz Jurczyk <mjurczyk@google.com> wrote:
> Check that the NFC_ATTR_TARGET_INDEX and NFC_ATTR_PROTOCOLS attributes (in
> addition to NFC_ATTR_DEVICE_INDEX) are provided by the netlink client
> prior to accessing them. This prevents potential unhandled NULL pointer
> dereference exceptions which can be triggered by malicious user-mode
> programs, if they omit one or both of these attributes.
>
> Signed-off-by: Mateusz Jurczyk <mjurczyk@google.com>

Acked-by: Kees Cook <keescook@chromium.org>

-Kees

> ---
>  net/nfc/netlink.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
> index 6b0850e63e09..b251fb936a27 100644
> --- a/net/nfc/netlink.c
> +++ b/net/nfc/netlink.c
> @@ -907,7 +907,9 @@ static int nfc_genl_activate_target(struct sk_buff *skb, struct genl_info *info)
>         u32 device_idx, target_idx, protocol;
>         int rc;
>
> -       if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
> +       if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
> +           !info->attrs[NFC_ATTR_TARGET_INDEX] ||
> +           !info->attrs[NFC_ATTR_PROTOCOLS])
>                 return -EINVAL;
>
>         device_idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
> --
> 2.13.0.219.gdb65acc882-goog
>



-- 
Kees Cook
Pixel Security

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