* [Linux-kernel-mentees] [PATCH] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id()
@ 2020-07-14 0:38 Peilin Ye
2020-07-14 0:53 ` Andrii Nakryiko
0 siblings, 1 reply; 7+ messages in thread
From: Peilin Ye @ 2020-07-14 0:38 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann
Cc: Song Liu, John Fastabend, linux-kernel, Martin KaFai Lau,
syzkaller-bugs, clang-built-linux, netdev, KP Singh,
Yonghong Song, bpf, Andrii Nakryiko, Peilin Ye,
linux-kernel-mentees
Prevent __btf_resolve_helper_id() from dereferencing `btf_vmlinux`
as NULL. This patch fixes the following syzbot bug:
https://syzkaller.appspot.com/bug?id=5edd146856fd513747c1992442732e5a0e9ba355
Reported-by: syzbot+ee09bda7017345f1fbe6@syzkaller.appspotmail.com
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
kernel/bpf/btf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 30721f2c2d10..3e981b183fa4 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -4088,7 +4088,7 @@ static int __btf_resolve_helper_id(struct bpf_verifier_log *log, void *fn,
const char *tname, *sym;
u32 btf_id, i;
- if (IS_ERR(btf_vmlinux)) {
+ if (IS_ERR_OR_NULL(btf_vmlinux)) {
bpf_log(log, "btf_vmlinux is malformed\n");
return -EINVAL;
}
--
2.25.1
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* Re: [Linux-kernel-mentees] [PATCH] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id()
2020-07-14 0:38 [Linux-kernel-mentees] [PATCH] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id() Peilin Ye
@ 2020-07-14 0:53 ` Andrii Nakryiko
2020-07-14 1:27 ` [Linux-kernel-mentees] [PATCH v2] " Peilin Ye
0 siblings, 1 reply; 7+ messages in thread
From: Andrii Nakryiko @ 2020-07-14 0:53 UTC (permalink / raw)
To: Peilin Ye
Cc: Song Liu, Daniel Borkmann, John Fastabend, Alexei Starovoitov,
open list, syzkaller-bugs, clang-built-linux, Networking,
KP Singh, Yonghong Song, bpf, Andrii Nakryiko, Martin KaFai Lau,
linux-kernel-mentees
On Mon, Jul 13, 2020 at 5:43 PM Peilin Ye <yepeilin.cs@gmail.com> wrote:
>
> Prevent __btf_resolve_helper_id() from dereferencing `btf_vmlinux`
> as NULL. This patch fixes the following syzbot bug:
>
> https://syzkaller.appspot.com/bug?id=5edd146856fd513747c1992442732e5a0e9ba355
>
> Reported-by: syzbot+ee09bda7017345f1fbe6@syzkaller.appspotmail.com
> Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
> ---
> kernel/bpf/btf.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
> index 30721f2c2d10..3e981b183fa4 100644
> --- a/kernel/bpf/btf.c
> +++ b/kernel/bpf/btf.c
> @@ -4088,7 +4088,7 @@ static int __btf_resolve_helper_id(struct bpf_verifier_log *log, void *fn,
> const char *tname, *sym;
> u32 btf_id, i;
>
> - if (IS_ERR(btf_vmlinux)) {
> + if (IS_ERR_OR_NULL(btf_vmlinux)) {
> bpf_log(log, "btf_vmlinux is malformed\n");
Can you please split IS_ERR and NULL cases and emit different messages
to log? If the kernel is not built with btf_vmlinux, saying that it's
"malformed" will confuse people. Thanks.
> return -EINVAL;
> }
> --
> 2.25.1
>
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* [Linux-kernel-mentees] [PATCH v2] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id()
2020-07-14 0:53 ` Andrii Nakryiko
@ 2020-07-14 1:27 ` Peilin Ye
2020-07-14 4:37 ` Andrii Nakryiko
0 siblings, 1 reply; 7+ messages in thread
From: Peilin Ye @ 2020-07-14 1:27 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Song Liu, Daniel Borkmann, John Fastabend, Alexei Starovoitov,
Peilin Ye, syzkaller-bugs, clang-built-linux, netdev, KP Singh,
Yonghong Song, bpf, linux-kernel-mentees, Martin KaFai Lau,
linux-kernel
Prevent __btf_resolve_helper_id() from dereferencing `btf_vmlinux`
as NULL. This patch fixes the following syzbot bug:
https://syzkaller.appspot.com/bug?id=5edd146856fd513747c1992442732e5a0e9ba355
Reported-by: syzbot+ee09bda7017345f1fbe6@syzkaller.appspotmail.com
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
Thank you for reviewing my patch! I am new to Linux kernel development; would
the log message and errno be appropriate for this case?
Change in v2:
- Split NULL and IS_ERR cases.
kernel/bpf/btf.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 30721f2c2d10..092116a311f4 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -4088,6 +4088,11 @@ static int __btf_resolve_helper_id(struct bpf_verifier_log *log, void *fn,
const char *tname, *sym;
u32 btf_id, i;
+ if (!btf_vmlinux) {
+ bpf_log(log, "btf_vmlinux doesn't exist\n");
+ return -EINVAL;
+ }
+
if (IS_ERR(btf_vmlinux)) {
bpf_log(log, "btf_vmlinux is malformed\n");
return -EINVAL;
--
2.25.1
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^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH v2] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id()
2020-07-14 1:27 ` [Linux-kernel-mentees] [PATCH v2] " Peilin Ye
@ 2020-07-14 4:37 ` Andrii Nakryiko
2020-07-14 17:27 ` Alexei Starovoitov
0 siblings, 1 reply; 7+ messages in thread
From: Andrii Nakryiko @ 2020-07-14 4:37 UTC (permalink / raw)
To: Peilin Ye
Cc: Song Liu, Daniel Borkmann, John Fastabend, Alexei Starovoitov,
open list, syzkaller-bugs, clang-built-linux, Networking,
KP Singh, Yonghong Song, bpf, Andrii Nakryiko, Martin KaFai Lau,
linux-kernel-mentees
On Mon, Jul 13, 2020 at 6:29 PM Peilin Ye <yepeilin.cs@gmail.com> wrote:
>
> Prevent __btf_resolve_helper_id() from dereferencing `btf_vmlinux`
> as NULL. This patch fixes the following syzbot bug:
>
> https://syzkaller.appspot.com/bug?id=5edd146856fd513747c1992442732e5a0e9ba355
>
> Reported-by: syzbot+ee09bda7017345f1fbe6@syzkaller.appspotmail.com
> Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
> ---
> Thank you for reviewing my patch! I am new to Linux kernel development; would
> the log message and errno be appropriate for this case?
I think it's good enough, thanks for the fix.
Acked-by: Andrii Nakryiko <andriin@fb.com>
>
> Change in v2:
> - Split NULL and IS_ERR cases.
>
> kernel/bpf/btf.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
[...]
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH v2] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id()
2020-07-14 4:37 ` Andrii Nakryiko
@ 2020-07-14 17:27 ` Alexei Starovoitov
2020-07-14 18:09 ` [Linux-kernel-mentees] [PATCH v3] " Peilin Ye
0 siblings, 1 reply; 7+ messages in thread
From: Alexei Starovoitov @ 2020-07-14 17:27 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Song Liu, Daniel Borkmann, John Fastabend, Alexei Starovoitov,
Peilin Ye, syzkaller-bugs, clang-built-linux, Networking,
KP Singh, Yonghong Song, bpf, Andrii Nakryiko, Martin KaFai Lau,
open list, linux-kernel-mentees
On Mon, Jul 13, 2020 at 9:38 PM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Mon, Jul 13, 2020 at 6:29 PM Peilin Ye <yepeilin.cs@gmail.com> wrote:
> >
> > Prevent __btf_resolve_helper_id() from dereferencing `btf_vmlinux`
> > as NULL. This patch fixes the following syzbot bug:
> >
> > https://syzkaller.appspot.com/bug?id=5edd146856fd513747c1992442732e5a0e9ba355
The link looks wrong?
Nothing in the stack trace indicates this issue.
> > Reported-by: syzbot+ee09bda7017345f1fbe6@syzkaller.appspotmail.com
> > Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
> > ---
> > Thank you for reviewing my patch! I am new to Linux kernel development; would
> > the log message and errno be appropriate for this case?
>
> I think it's good enough, thanks for the fix.
>
> Acked-by: Andrii Nakryiko <andriin@fb.com>
>
> >
> > Change in v2:
> > - Split NULL and IS_ERR cases.
> >
> > kernel/bpf/btf.c | 5 +++++
> > 1 file changed, 5 insertions(+)
> >
>
> [...]
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* [Linux-kernel-mentees] [PATCH v3] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id()
2020-07-14 17:27 ` Alexei Starovoitov
@ 2020-07-14 18:09 ` Peilin Ye
2020-07-15 21:07 ` Daniel Borkmann
0 siblings, 1 reply; 7+ messages in thread
From: Peilin Ye @ 2020-07-14 18:09 UTC (permalink / raw)
To: Andrii Nakryiko, Alexei Starovoitov
Cc: Song Liu, Daniel Borkmann, John Fastabend, linux-kernel,
Martin KaFai Lau, syzkaller-bugs, clang-built-linux, netdev,
KP Singh, Yonghong Song, bpf, linux-kernel-mentees, Peilin Ye
Prevent __btf_resolve_helper_id() from dereferencing `btf_vmlinux`
as NULL. This patch fixes the following syzbot bug:
https://syzkaller.appspot.com/bug?id=f823224ada908fa5c207902a5a62065e53ca0fcc
Reported-by: syzbot+ee09bda7017345f1fbe6@syzkaller.appspotmail.com
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
Sorry, I got the link wrong. Thank you for pointing that out.
Change in v3:
- Fix incorrect syzbot dashboard link.
Change in v2:
- Split NULL and IS_ERR cases.
kernel/bpf/btf.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 30721f2c2d10..092116a311f4 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -4088,6 +4088,11 @@ static int __btf_resolve_helper_id(struct bpf_verifier_log *log, void *fn,
const char *tname, *sym;
u32 btf_id, i;
+ if (!btf_vmlinux) {
+ bpf_log(log, "btf_vmlinux doesn't exist\n");
+ return -EINVAL;
+ }
+
if (IS_ERR(btf_vmlinux)) {
bpf_log(log, "btf_vmlinux is malformed\n");
return -EINVAL;
--
2.25.1
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^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [Linux-kernel-mentees] [PATCH v3] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id()
2020-07-14 18:09 ` [Linux-kernel-mentees] [PATCH v3] " Peilin Ye
@ 2020-07-15 21:07 ` Daniel Borkmann
0 siblings, 0 replies; 7+ messages in thread
From: Daniel Borkmann @ 2020-07-15 21:07 UTC (permalink / raw)
To: Peilin Ye, Andrii Nakryiko, Alexei Starovoitov
Cc: Song Liu, John Fastabend, linux-kernel, syzkaller-bugs,
clang-built-linux, netdev, KP Singh, Yonghong Song, bpf,
linux-kernel-mentees, Martin KaFai Lau
On 7/14/20 8:09 PM, Peilin Ye wrote:
> Prevent __btf_resolve_helper_id() from dereferencing `btf_vmlinux`
> as NULL. This patch fixes the following syzbot bug:
>
> https://syzkaller.appspot.com/bug?id=f823224ada908fa5c207902a5a62065e53ca0fcc
>
> Reported-by: syzbot+ee09bda7017345f1fbe6@syzkaller.appspotmail.com
> Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
Looks good, applied, thanks! As far as I can tell all the other occurrences are
gated behind btf_parse_vmlinux() where we also init struct_opts, etc.
So for bpf-next this would then end up looking like ...
int btf_resolve_helper_id(struct bpf_verifier_log *log,
const struct bpf_func_proto *fn, int arg)
{
int id;
if (fn->arg_type[arg] != ARG_PTR_TO_BTF_ID)
return -EINVAL;
id = fn->btf_id[arg];
if (!id || !btf_vmlinux || id > btf_vmlinux->nr_types)
return -EINVAL;
return id;
}
> ---
> Sorry, I got the link wrong. Thank you for pointing that out.
>
> Change in v3:
> - Fix incorrect syzbot dashboard link.
>
> Change in v2:
> - Split NULL and IS_ERR cases.
>
> kernel/bpf/btf.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
> index 30721f2c2d10..092116a311f4 100644
> --- a/kernel/bpf/btf.c
> +++ b/kernel/bpf/btf.c
> @@ -4088,6 +4088,11 @@ static int __btf_resolve_helper_id(struct bpf_verifier_log *log, void *fn,
> const char *tname, *sym;
> u32 btf_id, i;
>
> + if (!btf_vmlinux) {
> + bpf_log(log, "btf_vmlinux doesn't exist\n");
> + return -EINVAL;
> + }
> +
> if (IS_ERR(btf_vmlinux)) {
> bpf_log(log, "btf_vmlinux is malformed\n");
> return -EINVAL;
>
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end of thread, other threads:[~2020-07-15 21:07 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-14 0:38 [Linux-kernel-mentees] [PATCH] bpf: Fix NULL pointer dereference in __btf_resolve_helper_id() Peilin Ye
2020-07-14 0:53 ` Andrii Nakryiko
2020-07-14 1:27 ` [Linux-kernel-mentees] [PATCH v2] " Peilin Ye
2020-07-14 4:37 ` Andrii Nakryiko
2020-07-14 17:27 ` Alexei Starovoitov
2020-07-14 18:09 ` [Linux-kernel-mentees] [PATCH v3] " Peilin Ye
2020-07-15 21:07 ` Daniel Borkmann
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