* [Linux-kernel-mentees] [PATCH net] qrtr: Fix ZERO_SIZE_PTR deref in qrtr_tun_write_iter()
@ 2020-07-12 21:03 ` Peilin Ye
0 siblings, 0 replies; 6+ messages in thread
From: Peilin Ye @ 2020-07-12 21:03 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski
Cc: Peilin Ye, Navid Emamdoost, Christophe JAILLET,
Greg Kroah-Hartman, netdev, syzkaller-bugs, linux-kernel-mentees,
linux-kernel
qrtr_tun_write_iter() is dereferencing `ZERO_SIZE_PTR`s when `from->count`
equals to zero. Fix it by rejecting zero-length kzalloc() requests.
This patch fixes the following syzbot bug:
https://syzkaller.appspot.com/bug?id=f56bbe6668873ee245986bbd23312b895fa5a50a
Reported-by: syzbot+03e343dbccf82a5242a2@syzkaller.appspotmail.com
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
net/qrtr/tun.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/qrtr/tun.c b/net/qrtr/tun.c
index 15ce9b642b25..5465e94ba8e5 100644
--- a/net/qrtr/tun.c
+++ b/net/qrtr/tun.c
@@ -80,6 +80,9 @@ static ssize_t qrtr_tun_write_iter(struct kiocb *iocb, struct iov_iter *from)
ssize_t ret;
void *kbuf;
+ if (!len)
+ return -EINVAL;
+
kbuf = kzalloc(len, GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [Linux-kernel-mentees] [PATCH net] qrtr: Fix ZERO_SIZE_PTR deref in qrtr_tun_write_iter()
@ 2020-07-12 21:03 ` Peilin Ye
0 siblings, 0 replies; 6+ messages in thread
From: Peilin Ye @ 2020-07-12 21:03 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski
Cc: syzkaller-bugs, linux-kernel, Christophe JAILLET, netdev,
linux-kernel-mentees, Peilin Ye, Navid Emamdoost
qrtr_tun_write_iter() is dereferencing `ZERO_SIZE_PTR`s when `from->count`
equals to zero. Fix it by rejecting zero-length kzalloc() requests.
This patch fixes the following syzbot bug:
https://syzkaller.appspot.com/bug?id=f56bbe6668873ee245986bbd23312b895fa5a50a
Reported-by: syzbot+03e343dbccf82a5242a2@syzkaller.appspotmail.com
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
net/qrtr/tun.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/qrtr/tun.c b/net/qrtr/tun.c
index 15ce9b642b25..5465e94ba8e5 100644
--- a/net/qrtr/tun.c
+++ b/net/qrtr/tun.c
@@ -80,6 +80,9 @@ static ssize_t qrtr_tun_write_iter(struct kiocb *iocb, struct iov_iter *from)
ssize_t ret;
void *kbuf;
+ if (!len)
+ return -EINVAL;
+
kbuf = kzalloc(len, GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
--
2.25.1
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [Linux-kernel-mentees] [PATCH net] qrtr: Fix ZERO_SIZE_PTR deref in qrtr_tun_write_iter()
2020-07-12 21:03 ` Peilin Ye
@ 2020-07-12 21:36 ` Eric Biggers
-1 siblings, 0 replies; 6+ messages in thread
From: Eric Biggers @ 2020-07-12 21:36 UTC (permalink / raw)
To: Peilin Ye
Cc: David S . Miller, Jakub Kicinski, Navid Emamdoost,
Christophe JAILLET, Greg Kroah-Hartman, Dan Carpenter, netdev,
syzkaller-bugs, linux-kernel-mentees, linux-kernel
On Sun, Jul 12, 2020 at 05:03:00PM -0400, Peilin Ye wrote:
> qrtr_tun_write_iter() is dereferencing `ZERO_SIZE_PTR`s when `from->count`
> equals to zero. Fix it by rejecting zero-length kzalloc() requests.
>
> This patch fixes the following syzbot bug:
>
> https://syzkaller.appspot.com/bug?id=f56bbe6668873ee245986bbd23312b895fa5a50a
>
> Reported-by: syzbot+03e343dbccf82a5242a2@syzkaller.appspotmail.com
> Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
> ---
> net/qrtr/tun.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/net/qrtr/tun.c b/net/qrtr/tun.c
> index 15ce9b642b25..5465e94ba8e5 100644
> --- a/net/qrtr/tun.c
> +++ b/net/qrtr/tun.c
> @@ -80,6 +80,9 @@ static ssize_t qrtr_tun_write_iter(struct kiocb *iocb, struct iov_iter *from)
> ssize_t ret;
> void *kbuf;
>
> + if (!len)
> + return -EINVAL;
> +
> kbuf = kzalloc(len, GFP_KERNEL);
> if (!kbuf)
> return -ENOMEM;
Wasn't this already fixed by:
commit 8ff41cc21714704ef0158a546c3c4d07fae2c952
Author: Dan Carpenter <dan.carpenter@oracle.com>
Date: Tue Jun 30 14:46:15 2020 +0300
net: qrtr: Fix an out of bounds read qrtr_endpoint_post()
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Linux-kernel-mentees] [PATCH net] qrtr: Fix ZERO_SIZE_PTR deref in qrtr_tun_write_iter()
@ 2020-07-12 21:36 ` Eric Biggers
0 siblings, 0 replies; 6+ messages in thread
From: Eric Biggers @ 2020-07-12 21:36 UTC (permalink / raw)
To: Peilin Ye
Cc: syzkaller-bugs, linux-kernel, Christophe JAILLET, netdev,
Jakub Kicinski, linux-kernel-mentees, David S . Miller,
Dan Carpenter, Navid Emamdoost
On Sun, Jul 12, 2020 at 05:03:00PM -0400, Peilin Ye wrote:
> qrtr_tun_write_iter() is dereferencing `ZERO_SIZE_PTR`s when `from->count`
> equals to zero. Fix it by rejecting zero-length kzalloc() requests.
>
> This patch fixes the following syzbot bug:
>
> https://syzkaller.appspot.com/bug?id=f56bbe6668873ee245986bbd23312b895fa5a50a
>
> Reported-by: syzbot+03e343dbccf82a5242a2@syzkaller.appspotmail.com
> Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
> ---
> net/qrtr/tun.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/net/qrtr/tun.c b/net/qrtr/tun.c
> index 15ce9b642b25..5465e94ba8e5 100644
> --- a/net/qrtr/tun.c
> +++ b/net/qrtr/tun.c
> @@ -80,6 +80,9 @@ static ssize_t qrtr_tun_write_iter(struct kiocb *iocb, struct iov_iter *from)
> ssize_t ret;
> void *kbuf;
>
> + if (!len)
> + return -EINVAL;
> +
> kbuf = kzalloc(len, GFP_KERNEL);
> if (!kbuf)
> return -ENOMEM;
Wasn't this already fixed by:
commit 8ff41cc21714704ef0158a546c3c4d07fae2c952
Author: Dan Carpenter <dan.carpenter@oracle.com>
Date: Tue Jun 30 14:46:15 2020 +0300
net: qrtr: Fix an out of bounds read qrtr_endpoint_post()
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Linux-kernel-mentees] [PATCH net] qrtr: Fix ZERO_SIZE_PTR deref in qrtr_tun_write_iter()
2020-07-12 21:36 ` Eric Biggers
@ 2020-07-13 9:13 ` Dan Carpenter
-1 siblings, 0 replies; 6+ messages in thread
From: Dan Carpenter @ 2020-07-13 9:13 UTC (permalink / raw)
To: Eric Biggers
Cc: Peilin Ye, David S . Miller, Jakub Kicinski, Navid Emamdoost,
Christophe JAILLET, Greg Kroah-Hartman, netdev, syzkaller-bugs,
linux-kernel-mentees, linux-kernel
On Sun, Jul 12, 2020 at 02:36:31PM -0700, Eric Biggers wrote:
> On Sun, Jul 12, 2020 at 05:03:00PM -0400, Peilin Ye wrote:
> > qrtr_tun_write_iter() is dereferencing `ZERO_SIZE_PTR`s when `from->count`
> > equals to zero. Fix it by rejecting zero-length kzalloc() requests.
> >
> > This patch fixes the following syzbot bug:
> >
> > https://syzkaller.appspot.com/bug?id=f56bbe6668873ee245986bbd23312b895fa5a50a
> >
> > Reported-by: syzbot+03e343dbccf82a5242a2@syzkaller.appspotmail.com
> > Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
> > ---
> > net/qrtr/tun.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/net/qrtr/tun.c b/net/qrtr/tun.c
> > index 15ce9b642b25..5465e94ba8e5 100644
> > --- a/net/qrtr/tun.c
> > +++ b/net/qrtr/tun.c
> > @@ -80,6 +80,9 @@ static ssize_t qrtr_tun_write_iter(struct kiocb *iocb, struct iov_iter *from)
> > ssize_t ret;
> > void *kbuf;
> >
> > + if (!len)
> > + return -EINVAL;
> > +
> > kbuf = kzalloc(len, GFP_KERNEL);
> > if (!kbuf)
> > return -ENOMEM;
>
> Wasn't this already fixed by:
>
> commit 8ff41cc21714704ef0158a546c3c4d07fae2c952
> Author: Dan Carpenter <dan.carpenter@oracle.com>
> Date: Tue Jun 30 14:46:15 2020 +0300
>
> net: qrtr: Fix an out of bounds read qrtr_endpoint_post()
Yep. If you're using kmalloc() you can allocate a zero byte buffer but
you just can't access the array. for (i = 0; i < 0; i++) works.
It's interesting because at the time, I wrote the patch I thought "len"
probably couldn't be zero but I just checked it for completeness and
readability.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH net] qrtr: Fix ZERO_SIZE_PTR deref in qrtr_tun_write_iter()
@ 2020-07-13 9:13 ` Dan Carpenter
0 siblings, 0 replies; 6+ messages in thread
From: Dan Carpenter @ 2020-07-13 9:13 UTC (permalink / raw)
To: Eric Biggers
Cc: syzkaller-bugs, linux-kernel, David S . Miller,
Christophe JAILLET, netdev, Jakub Kicinski, linux-kernel-mentees,
Peilin Ye, Navid Emamdoost
On Sun, Jul 12, 2020 at 02:36:31PM -0700, Eric Biggers wrote:
> On Sun, Jul 12, 2020 at 05:03:00PM -0400, Peilin Ye wrote:
> > qrtr_tun_write_iter() is dereferencing `ZERO_SIZE_PTR`s when `from->count`
> > equals to zero. Fix it by rejecting zero-length kzalloc() requests.
> >
> > This patch fixes the following syzbot bug:
> >
> > https://syzkaller.appspot.com/bug?id=f56bbe6668873ee245986bbd23312b895fa5a50a
> >
> > Reported-by: syzbot+03e343dbccf82a5242a2@syzkaller.appspotmail.com
> > Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
> > ---
> > net/qrtr/tun.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/net/qrtr/tun.c b/net/qrtr/tun.c
> > index 15ce9b642b25..5465e94ba8e5 100644
> > --- a/net/qrtr/tun.c
> > +++ b/net/qrtr/tun.c
> > @@ -80,6 +80,9 @@ static ssize_t qrtr_tun_write_iter(struct kiocb *iocb, struct iov_iter *from)
> > ssize_t ret;
> > void *kbuf;
> >
> > + if (!len)
> > + return -EINVAL;
> > +
> > kbuf = kzalloc(len, GFP_KERNEL);
> > if (!kbuf)
> > return -ENOMEM;
>
> Wasn't this already fixed by:
>
> commit 8ff41cc21714704ef0158a546c3c4d07fae2c952
> Author: Dan Carpenter <dan.carpenter@oracle.com>
> Date: Tue Jun 30 14:46:15 2020 +0300
>
> net: qrtr: Fix an out of bounds read qrtr_endpoint_post()
Yep. If you're using kmalloc() you can allocate a zero byte buffer but
you just can't access the array. for (i = 0; i < 0; i++) works.
It's interesting because at the time, I wrote the patch I thought "len"
probably couldn't be zero but I just checked it for completeness and
readability.
regards,
dan carpenter
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-07-13 9:13 UTC | newest]
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2020-07-12 21:03 [Linux-kernel-mentees] [PATCH net] qrtr: Fix ZERO_SIZE_PTR deref in qrtr_tun_write_iter() Peilin Ye
2020-07-12 21:03 ` Peilin Ye
2020-07-12 21:36 ` Eric Biggers
2020-07-12 21:36 ` Eric Biggers
2020-07-13 9:13 ` Dan Carpenter
2020-07-13 9:13 ` Dan Carpenter
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