* [PATCH v2] wireless/nl80211.c: fix uninitialized variable
@ 2021-03-30 17:22 Alaa Emad
2021-03-30 19:26 ` Eric Dumazet
0 siblings, 1 reply; 4+ messages in thread
From: Alaa Emad @ 2021-03-30 17:22 UTC (permalink / raw)
To: johannes, davem, kuba
Cc: gregkh, linux-wireless, netdev, linux-kernel, syzkaller,
Alaa Emad, syzbot+72b99dcf4607e8c770f3
This change fix KMSAN uninit-value in net/wireless/nl80211.c:225 , That
because of `fixedlen` variable uninitialized,So I initialized it by zero.
Reported-by: syzbot+72b99dcf4607e8c770f3@syzkaller.appspotmail.com
Signed-off-by: Alaa Emad <alaaemadhossney.ae@gmail.com>
---
Changes in v2:
- Make the commit message more clearer.
---
net/wireless/nl80211.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 775d0c4d86c3..b87ab67ad33d 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -210,7 +210,7 @@ static int validate_beacon_head(const struct nlattr *attr,
const struct element *elem;
const struct ieee80211_mgmt *mgmt = (void *)data;
bool s1g_bcn = ieee80211_is_s1g_beacon(mgmt->frame_control);
- unsigned int fixedlen, hdrlen;
+ unsigned int fixedlen = 0, hdrlen;
if (s1g_bcn) {
fixedlen = offsetof(struct ieee80211_ext,
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v2] wireless/nl80211.c: fix uninitialized variable
2021-03-30 17:22 [PATCH v2] wireless/nl80211.c: fix uninitialized variable Alaa Emad
@ 2021-03-30 19:26 ` Eric Dumazet
0 siblings, 0 replies; 4+ messages in thread
From: Eric Dumazet @ 2021-03-30 19:26 UTC (permalink / raw)
To: Alaa Emad, johannes, davem, kuba
Cc: gregkh, linux-wireless, netdev, linux-kernel, syzkaller,
syzbot+72b99dcf4607e8c770f3
On 3/30/21 7:22 PM, Alaa Emad wrote:
> This change fix KMSAN uninit-value in net/wireless/nl80211.c:225 , That
> because of `fixedlen` variable uninitialized,So I initialized it by zero.
>
> Reported-by: syzbot+72b99dcf4607e8c770f3@syzkaller.appspotmail.com
> Signed-off-by: Alaa Emad <alaaemadhossney.ae@gmail.com>
> ---
> Changes in v2:
> - Make the commit message more clearer.
> ---
> net/wireless/nl80211.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
> index 775d0c4d86c3..b87ab67ad33d 100644
> --- a/net/wireless/nl80211.c
> +++ b/net/wireless/nl80211.c
> @@ -210,7 +210,7 @@ static int validate_beacon_head(const struct nlattr *attr,
> const struct element *elem;
> const struct ieee80211_mgmt *mgmt = (void *)data;
> bool s1g_bcn = ieee80211_is_s1g_beacon(mgmt->frame_control);
> - unsigned int fixedlen, hdrlen;
> + unsigned int fixedlen = 0, hdrlen;
>
> if (s1g_bcn) {
> fixedlen = offsetof(struct ieee80211_ext,
>
What was the report exactly ?
Current code does :
unsigned int fixedlen;
if (s1g_bcn) {
fixedlen = something1;
...
else {
fixedlen = something2;
...
}
So your patch does nothing.
Initial value of @fixedlen is not relevant.
Reading this code (without access to KMSAN report) I suspect the issue
is more like the following :
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 775d0c4d86c3..d815261917ff 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -209,9 +209,12 @@ static int validate_beacon_head(const struct nlattr *attr,
unsigned int len = nla_len(attr);
const struct element *elem;
const struct ieee80211_mgmt *mgmt = (void *)data;
- bool s1g_bcn = ieee80211_is_s1g_beacon(mgmt->frame_control);
unsigned int fixedlen, hdrlen;
+ bool s1g_bcn;
+ if (len < offsetofend(typeof(*mgmt), frame_control))
+ goto err;
+ s1g_bcn = ieee80211_is_s1g_beacon(mgmt->frame_control);
if (s1g_bcn) {
fixedlen = offsetof(struct ieee80211_ext,
u.s1g_beacon.variable);
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v2] wireless/nl80211.c: fix uninitialized variable
@ 2021-03-30 16:37 Alaa Emad
2021-03-30 17:14 ` Greg KH
0 siblings, 1 reply; 4+ messages in thread
From: Alaa Emad @ 2021-03-30 16:37 UTC (permalink / raw)
To: johannes, davem, kuba
Cc: gregkh, linux-wireless, netdev, linux-kernel, syzkaller,
Alaa Emad, syzbot+72b99dcf4607e8c770f3
This change fix KMSAN uninit-value in net/wireless/nl80211.c:225 , That
because of `fixedlen` variable uninitialized,So I initialized it by zero.
Reported-by: syzbot+72b99dcf4607e8c770f3@syzkaller.appspotmail.com
Signed-off-by: Alaa Emad <alaaemadhossney.ae@gmail.com>
---
Changes in v2:
- Make the commit message more clearer.
---
net/wireless/nl80211.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 775d0c4d86c3..b87ab67ad33d 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -210,7 +210,7 @@ static int validate_beacon_head(const struct nlattr *attr,
const struct element *elem;
const struct ieee80211_mgmt *mgmt = (void *)data;
bool s1g_bcn = ieee80211_is_s1g_beacon(mgmt->frame_control);
- unsigned int fixedlen, hdrlen;
+ unsigned int fixedlen = 0 , hdrlen;
if (s1g_bcn) {
fixedlen = offsetof(struct ieee80211_ext,
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v2] wireless/nl80211.c: fix uninitialized variable
2021-03-30 16:37 Alaa Emad
@ 2021-03-30 17:14 ` Greg KH
0 siblings, 0 replies; 4+ messages in thread
From: Greg KH @ 2021-03-30 17:14 UTC (permalink / raw)
To: Alaa Emad
Cc: johannes, davem, kuba, linux-wireless, netdev, linux-kernel,
syzkaller, syzbot+72b99dcf4607e8c770f3
On Tue, Mar 30, 2021 at 06:37:05PM +0200, Alaa Emad wrote:
> This change fix KMSAN uninit-value in net/wireless/nl80211.c:225 , That
> because of `fixedlen` variable uninitialized,So I initialized it by zero.
>
> Reported-by: syzbot+72b99dcf4607e8c770f3@syzkaller.appspotmail.com
> Signed-off-by: Alaa Emad <alaaemadhossney.ae@gmail.com>
> ---
> Changes in v2:
> - Make the commit message more clearer.
> ---
> net/wireless/nl80211.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
> index 775d0c4d86c3..b87ab67ad33d 100644
> --- a/net/wireless/nl80211.c
> +++ b/net/wireless/nl80211.c
> @@ -210,7 +210,7 @@ static int validate_beacon_head(const struct nlattr *attr,
> const struct element *elem;
> const struct ieee80211_mgmt *mgmt = (void *)data;
> bool s1g_bcn = ieee80211_is_s1g_beacon(mgmt->frame_control);
> - unsigned int fixedlen, hdrlen;
> + unsigned int fixedlen = 0 , hdrlen;
Please always use scripts/checkpatch.pl before sending out patches. It
would have pointed out that this line is incorrect and needs to be fixed
up :(
thanks,
greg k-h
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-03-30 16:37 Alaa Emad
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