2019-05-14 08:10:10

by Yue Haibing

Subject: [PATCH] ppp: deflate: Fix possible crash in deflate_init

BUG: unable to handle kernel paging request at ffffffffa018f000
PGD 3270067 P4D 3270067 PUD 3271063 PMD 2307eb067 PTE 0
Oops: 0000 [#1] PREEMPT SMP
CPU: 0 PID: 4138 Comm: modprobe Not tainted 5.1.0-rc7+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014
RIP: 0010:ppp_register_compressor+0x3e/0xd0 [ppp_generic]
Code: 98 4a 3f e2 48 8b 15 c1 67 00 00 41 8b 0c 24 48 81 fa 40 f0 19 a0
75 0e eb 35 48 8b 12 48 81 fa 40 f0 19 a0 74
RSP: 0018:ffffc90000d93c68 EFLAGS: 00010287
RAX: ffffffffa018f000 RBX: ffffffffa01a3000 RCX: 000000000000001a
RDX: ffff888230c750a0 RSI: 0000000000000000 RDI: ffffffffa019f000
RBP: ffffc90000d93c80 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffa0194080
R13: ffff88822ee1a700 R14: 0000000000000000 R15: ffffc90000d93e78
FS: 00007f2339557540(0000) GS:ffff888237a00000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffa018f000 CR3: 000000022bde4000 CR4: 00000000000006f0
Call Trace:
? 0xffffffffa01a3000
deflate_init+0x11/0x1000 [ppp_deflate]
? 0xffffffffa01a3000
do_one_initcall+0x6c/0x3cc
? kmem_cache_alloc_trace+0x248/0x3b0
do_init_module+0x5b/0x1f1
load_module+0x1db1/0x2690
? m_show+0x1d0/0x1d0
__do_sys_finit_module+0xc5/0xd0
__x64_sys_finit_module+0x15/0x20
do_syscall_64+0x6b/0x1d0
entry_SYSCALL_64_after_hwframe+0x49/0xbe

If ppp_deflate fails to register in deflate_init,
module initialization failed out, however
ppp_deflate_draft may has been regiestred and not
unregistered before return.
Then the seconed modprobe will trigger crash like this.

Reported-by: Hulk Robot <[email protected]>
Signed-off-by: YueHaibing <[email protected]>
---
drivers/net/ppp/ppp_deflate.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ppp/ppp_deflate.c b/drivers/net/ppp/ppp_deflate.c
index b5edc7f..2829efe 100644
--- a/drivers/net/ppp/ppp_deflate.c
+++ b/drivers/net/ppp/ppp_deflate.c
@@ -610,12 +610,16 @@ static void z_incomp(void *arg, unsigned char *ibuf, int icnt)

static int __init deflate_init(void)
{
- int answer = ppp_register_compressor(&ppp_deflate);
- if (answer == 0)
- printk(KERN_INFO
- "PPP Deflate Compression module registered\n");
+ int answer;
+
+ answer = ppp_register_compressor(&ppp_deflate);
+ if (answer)
+ return answer;
+
+ pr_info("PPP Deflate Compression module registered\n");
ppp_register_compressor(&ppp_deflate_draft);
- return answer;
+
+ return 0;
}

static void __exit deflate_cleanup(void)
--
1.8.3.1

2019-05-14 14:09:28

by Guillaume Nault

Subject: Re: [PATCH] ppp: deflate: Fix possible crash in deflate_init

On Tue, May 14, 2019 at 03:43:00PM +0800, YueHaibing wrote:
>
> If ppp_deflate fails to register in deflate_init,
> module initialization failed out, however
> ppp_deflate_draft may has been regiestred and not
> unregistered before return.
> Then the seconed modprobe will trigger crash like this.
>
> Reported-by: Hulk Robot <[email protected]>
> Signed-off-by: YueHaibing <[email protected]>
> ---
> drivers/net/ppp/ppp_deflate.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/ppp/ppp_deflate.c b/drivers/net/ppp/ppp_deflate.c
> index b5edc7f..2829efe 100644
> --- a/drivers/net/ppp/ppp_deflate.c
> +++ b/drivers/net/ppp/ppp_deflate.c
> @@ -610,12 +610,16 @@ static void z_incomp(void *arg, unsigned char *ibuf, int icnt)
>
> static int __init deflate_init(void)
> {
> - int answer = ppp_register_compressor(&ppp_deflate);
> - if (answer == 0)
> - printk(KERN_INFO
> - "PPP Deflate Compression module registered\n");
> + int answer;
> +
> + answer = ppp_register_compressor(&ppp_deflate);
> + if (answer)
> + return answer;
> +
> + pr_info("PPP Deflate Compression module registered\n");
> ppp_register_compressor(&ppp_deflate_draft);
> - return answer;
> +
> + return 0;
> }
>
I'd be cleaner to also check for ppp_deflate_draft registration failure
IMHO (and print the log line only if both compressors get registered
successfully).

2019-05-14 14:46:09

by Yue Haibing

Subject: Re: [PATCH] ppp: deflate: Fix possible crash in deflate_init

On 2019/5/14 22:05, Guillaume Nault wrote:
> On Tue, May 14, 2019 at 03:43:00PM +0800, YueHaibing wrote:
>>
>> If ppp_deflate fails to register in deflate_init,
>> module initialization failed out, however
>> ppp_deflate_draft may has been regiestred and not
>> unregistered before return.
>> Then the seconed modprobe will trigger crash like this.
>>
>> Reported-by: Hulk Robot <[email protected]>
>> Signed-off-by: YueHaibing <[email protected]>
>> ---
>> drivers/net/ppp/ppp_deflate.c | 14 +++++++++-----
>> 1 file changed, 9 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/net/ppp/ppp_deflate.c b/drivers/net/ppp/ppp_deflate.c
>> index b5edc7f..2829efe 100644
>> --- a/drivers/net/ppp/ppp_deflate.c
>> +++ b/drivers/net/ppp/ppp_deflate.c
>> @@ -610,12 +610,16 @@ static void z_incomp(void *arg, unsigned char *ibuf, int icnt)
>>
>> static int __init deflate_init(void)
>> {
>> - int answer = ppp_register_compressor(&ppp_deflate);
>> - if (answer == 0)
>> - printk(KERN_INFO
>> - "PPP Deflate Compression module registered\n");
>> + int answer;
>> +
>> + answer = ppp_register_compressor(&ppp_deflate);
>> + if (answer)
>> + return answer;
>> +
>> + pr_info("PPP Deflate Compression module registered\n");
>> ppp_register_compressor(&ppp_deflate_draft);
>> - return answer;
>> +
>> + return 0;
>> }
>>
> I'd be cleaner to also check for ppp_deflate_draft registration failure
> IMHO (and print the log line only if both compressors get registered
> successfully).

Ok, will send v2 to do that, thanks!

>
> .
>

2019-05-14 15:02:43

by Yue Haibing

Subject: [PATCH v2] ppp: deflate: Fix possible crash in deflate_init

BUG: unable to handle kernel paging request at ffffffffa018f000
PGD 3270067 P4D 3270067 PUD 3271063 PMD 2307eb067 PTE 0
Oops: 0000 [#1] PREEMPT SMP
CPU: 0 PID: 4138 Comm: modprobe Not tainted 5.1.0-rc7+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014
RIP: 0010:ppp_register_compressor+0x3e/0xd0 [ppp_generic]
Code: 98 4a 3f e2 48 8b 15 c1 67 00 00 41 8b 0c 24 48 81 fa 40 f0 19 a0
75 0e eb 35 48 8b 12 48 81 fa 40 f0 19 a0 74
RSP: 0018:ffffc90000d93c68 EFLAGS: 00010287
RAX: ffffffffa018f000 RBX: ffffffffa01a3000 RCX: 000000000000001a
RDX: ffff888230c750a0 RSI: 0000000000000000 RDI: ffffffffa019f000
RBP: ffffc90000d93c80 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffa0194080
R13: ffff88822ee1a700 R14: 0000000000000000 R15: ffffc90000d93e78
FS: 00007f2339557540(0000) GS:ffff888237a00000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffa018f000 CR3: 000000022bde4000 CR4: 00000000000006f0
Call Trace:
? 0xffffffffa01a3000
deflate_init+0x11/0x1000 [ppp_deflate]
? 0xffffffffa01a3000
do_one_initcall+0x6c/0x3cc
? kmem_cache_alloc_trace+0x248/0x3b0
do_init_module+0x5b/0x1f1
load_module+0x1db1/0x2690
? m_show+0x1d0/0x1d0
__do_sys_finit_module+0xc5/0xd0
__x64_sys_finit_module+0x15/0x20
do_syscall_64+0x6b/0x1d0
entry_SYSCALL_64_after_hwframe+0x49/0xbe

If ppp_deflate fails to register in deflate_init,
module initialization failed out, however
ppp_deflate_draft may has been regiestred and not
unregistered before return.
Then the seconed modprobe will trigger crash like this.

Reported-by: Hulk Robot <[email protected]>
Signed-off-by: YueHaibing <[email protected]>
---
v2: also check ppp_deflate_draft registration
---
drivers/net/ppp/ppp_deflate.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ppp/ppp_deflate.c b/drivers/net/ppp/ppp_deflate.c
index b5edc7f..685e875 100644
--- a/drivers/net/ppp/ppp_deflate.c
+++ b/drivers/net/ppp/ppp_deflate.c
@@ -610,12 +610,20 @@ static void z_incomp(void *arg, unsigned char *ibuf, int icnt)

static int __init deflate_init(void)
{
- int answer = ppp_register_compressor(&ppp_deflate);
- if (answer == 0)
- printk(KERN_INFO
- "PPP Deflate Compression module registered\n");
- ppp_register_compressor(&ppp_deflate_draft);
- return answer;
+ int rc;
+
+ rc = ppp_register_compressor(&ppp_deflate);
+ if (rc)
+ return rc;
+
+ rc = ppp_register_compressor(&ppp_deflate_draft);
+ if (rc) {
+ ppp_unregister_compressor(&ppp_deflate);
+ return rc;
+ }
+
+ pr_info("PPP Deflate Compression module registered\n");
+ return 0;
}

static void __exit deflate_cleanup(void)
--
1.8.3.1

2019-05-14 15:36:58

by Guillaume Nault

Subject: Re: [PATCH v2] ppp: deflate: Fix possible crash in deflate_init

On Tue, May 14, 2019 at 10:55:32PM +0800, YueHaibing wrote:
> If ppp_deflate fails to register in deflate_init,
> module initialization failed out, however
> ppp_deflate_draft may has been regiestred and not
> unregistered before return.
>
Thanks!

Acked-by: Guillaume Nault <[email protected]>

2019-05-14 22:44:33

by David Miller

Subject: Re: [PATCH v2] ppp: deflate: Fix possible crash in deflate_init

From: YueHaibing <[email protected]>
Date: Tue, 14 May 2019 22:55:32 +0800

> BUG: unable to handle kernel paging request at ffffffffa018f000
...
> If ppp_deflate fails to register in deflate_init,
> module initialization failed out, however
> ppp_deflate_draft may has been regiestred and not
> unregistered before return.
> Then the seconed modprobe will trigger crash like this.
>
> Reported-by: Hulk Robot <[email protected]>
> Signed-off-by: YueHaibing <[email protected]>
> ---
> v2: also check ppp_deflate_draft registration

Applied and queued up for -stable, thanks.