2019-04-12 12:42:29

by Alban Crequy

Subject: [PATCH bpf v2] tools: bpftool: fix infinite loop in map create

From: Alban Crequy <[email protected]>

"bpftool map create" has an infinite loop on "while (argc)". The error
case is missing.

Symptoms: when forgetting to type the keyword 'type' in front of 'hash':
$ sudo bpftool map create /sys/fs/bpf/dir/foobar hash key 8 value 8 entries 128
(infinite loop, taking all the CPU)
^C

After the patch:
$ sudo bpftool map create /sys/fs/bpf/dir/foobar hash key 8 value 8 entries 128
Error: unknown arg hash

Fixes: 0b592b5a01be ("tools: bpftool: add map create command")
Signed-off-by: Alban Crequy <[email protected]>

---

Changes in v2:
- Explain the cause of the bug in commitmsg
- Add the "fixes" line in the commitmsg (Jakub's review)
- Rebase on the bpf tree

v1 was initially based on bpf-next and submitted on
https://marc.info/?l=linux-kernel&m=155310327709613&w=2
---
tools/bpf/bpftool/map.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 05b029b934a6..1ccc38718458 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -1151,6 +1151,9 @@ static int do_create(int argc, char **argv)
return -1;
}
NEXT_ARG();
+ } else {
+ p_err("unknown arg %s", *argv);
+ return -1;
}
}

--
2.20.1

2019-04-12 13:22:12

by Quentin Monnet

Subject: Re: [PATCH bpf v2] tools: bpftool: fix infinite loop in map create

2019-04-12 14:40 UTC+0200 ~ Alban Crequy <[email protected]>
> From: Alban Crequy <[email protected]>
>
> "bpftool map create" has an infinite loop on "while (argc)". The error
> case is missing.
>
> Symptoms: when forgetting to type the keyword 'type' in front of 'hash':
> $ sudo bpftool map create /sys/fs/bpf/dir/foobar hash key 8 value 8 entries 128
> (infinite loop, taking all the CPU)
> ^C
>
> After the patch:
> $ sudo bpftool map create /sys/fs/bpf/dir/foobar hash key 8 value 8 entries 128
> Error: unknown arg hash
>
> Fixes: 0b592b5a01be ("tools: bpftool: add map create command")
> Signed-off-by: Alban Crequy <[email protected]>
>
> ---
>
> Changes in v2:
> - Explain the cause of the bug in commitmsg
> - Add the "fixes" line in the commitmsg (Jakub's review)
> - Rebase on the bpf tree
>
> v1 was initially based on bpf-next and submitted on
> https://marc.info/?l=linux-kernel&m=155310327709613&w=2
> ---
> tools/bpf/bpftool/map.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
> index 05b029b934a6..1ccc38718458 100644
> --- a/tools/bpf/bpftool/map.c
> +++ b/tools/bpf/bpftool/map.c
> @@ -1151,6 +1151,9 @@ static int do_create(int argc, char **argv)
> return -1;
> }
> NEXT_ARG();
> + } else {
> + p_err("unknown arg %s", *argv);
> + return -1;
> }
> }
>
>

Reviewed-by: Quentin Monnet <[email protected]>

Thanks Alban!

2019-04-12 18:10:03

by Song Liu

Subject: Re: [PATCH bpf v2] tools: bpftool: fix infinite loop in map create

On Fri, Apr 12, 2019 at 6:21 AM Quentin Monnet
<[email protected]> wrote:
>
> 2019-04-12 14:40 UTC+0200 ~ Alban Crequy <[email protected]>
> > From: Alban Crequy <[email protected]>
> >
> > "bpftool map create" has an infinite loop on "while (argc)". The error
> > case is missing.
> >
> > Symptoms: when forgetting to type the keyword 'type' in front of 'hash':
> > $ sudo bpftool map create /sys/fs/bpf/dir/foobar hash key 8 value 8 entries 128
> > (infinite loop, taking all the CPU)
> > ^C
> >
> > After the patch:
> > $ sudo bpftool map create /sys/fs/bpf/dir/foobar hash key 8 value 8 entries 128
> > Error: unknown arg hash
> >
> > Fixes: 0b592b5a01be ("tools: bpftool: add map create command")
> > Signed-off-by: Alban Crequy <[email protected]>

Acked-by: Song Liu <[email protected]>

Thanks for the fix!

> >
> > ---
> >
> > Changes in v2:
> > - Explain the cause of the bug in commitmsg
> > - Add the "fixes" line in the commitmsg (Jakub's review)
> > - Rebase on the bpf tree
> >
> > v1 was initially based on bpf-next and submitted on
> > https://marc.info/?l=linux-kernel&m=155310327709613&w=2
> > ---
> > tools/bpf/bpftool/map.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
> > index 05b029b934a6..1ccc38718458 100644
> > --- a/tools/bpf/bpftool/map.c
> > +++ b/tools/bpf/bpftool/map.c
> > @@ -1151,6 +1151,9 @@ static int do_create(int argc, char **argv)
> > return -1;
> > }
> > NEXT_ARG();
> > + } else {
> > + p_err("unknown arg %s", *argv);
> > + return -1;
> > }
> > }
> >
> >
>
> Reviewed-by: Quentin Monnet <[email protected]>
>
> Thanks Alban!

2019-04-12 23:46:13

by Jakub Kicinski

Subject: Re: [PATCH bpf v2] tools: bpftool: fix infinite loop in map create

On Fri, 12 Apr 2019 14:40:50 +0200, Alban Crequy wrote:
> From: Alban Crequy <[email protected]>
>
> "bpftool map create" has an infinite loop on "while (argc)". The error
> case is missing.
>
> Symptoms: when forgetting to type the keyword 'type' in front of 'hash':
> $ sudo bpftool map create /sys/fs/bpf/dir/foobar hash key 8 value 8 entries 128
> (infinite loop, taking all the CPU)
> ^C
>
> After the patch:
> $ sudo bpftool map create /sys/fs/bpf/dir/foobar hash key 8 value 8 entries 128
> Error: unknown arg hash
>
> Fixes: 0b592b5a01be ("tools: bpftool: add map create command")
> Signed-off-by: Alban Crequy <[email protected]>

Reviewed-by: Jakub Kicinski <[email protected]>

2019-04-16 09:29:57

by Daniel Borkmann

Subject: Re: [PATCH bpf v2] tools: bpftool: fix infinite loop in map create

On 04/12/2019 02:40 PM, Alban Crequy wrote:
> From: Alban Crequy <[email protected]>
>
> "bpftool map create" has an infinite loop on "while (argc)". The error
> case is missing.
>
> Symptoms: when forgetting to type the keyword 'type' in front of 'hash':
> $ sudo bpftool map create /sys/fs/bpf/dir/foobar hash key 8 value 8 entries 128
> (infinite loop, taking all the CPU)
> ^C
>
> After the patch:
> $ sudo bpftool map create /sys/fs/bpf/dir/foobar hash key 8 value 8 entries 128
> Error: unknown arg hash
>
> Fixes: 0b592b5a01be ("tools: bpftool: add map create command")
> Signed-off-by: Alban Crequy <[email protected]>

Applied, thanks!