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* [dm-devel] [PATCH]dm_get_map: fix segfault when can't found target
@ 2022-05-27  2:27 Wu Guanghao
  2022-05-27 19:35 ` Benjamin Marzinski
  0 siblings, 1 reply; 3+ messages in thread
From: Wu Guanghao @ 2022-05-27  2:27 UTC (permalink / raw)
  To: Christophe Varoqui, Benjamin Marzinski, Martin Wilck,
	dm-devel mailing list
  Cc: lixiaokeng, linfeilong

We got a segfault when we test multipath + iscsi.

(gdb) bt
#0  __strlen_avx2 () at ../sysdeps/x86_64/multiarch/strlen-avx2.S:74
#1  0x00007f694306cd23 in __GI___strdup (s=0x0) at strdup.c:41
#2  0x00007f69433a147c in dm_get_map (name=0x55d4bc090320 "3600140537cde137ea8c43d8a971462c7",
    size=size@entry=0x55d4bc0270d8, outparams=outparams@entry=0x7f6941add640) at devmapper.c:688
#3  0x00007f69433cbbdf in update_multipath_table (mpp=mpp@entry=0x55d4bc026f30,
    pathvec=pathvec@entry=0x55d4bc063990, flags=flags@entry=0) at structs_vec.c:426
#4  0x00007f69433cbfe5 in update_multipath_strings (mpp=0x55d4bc026f30, pathvec=0x55d4bc063990)
    at structs_vec.c:526
#5  0x000055d4bb52e03e in check_path (vecs=0x55d4bbfad760, pp=0x7f692402d270, ticks=<optimized out>)
    at main.c:2280
#6  0x000055d4bb52f3e2 in checkerloop (ap=0x55d4bbfad760) at main.c:2542
#7  0x00007f694305b3ba in start_thread (arg=<optimized out>) at pthread_create.c:443
#8  0x00007f69430ddb40 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
(gdb) f 2
#2  0x00007f69433a147c in dm_get_map (name=0x55d4bc090320 "3600140537cde137ea8c43d8a971462c7",
    size=size@entry=0x55d4bc0270d8, outparams=outparams@entry=0x7f6941add640) at devmapper.c:688
688			*outparams = strdup(params);
(gdb) l
683			*size = length;
684	
685		if (!outparams)
686			r = DMP_OK;
687		else {
688			*outparams = strdup(params);
689			r = *outparams ? DMP_OK : DMP_ERR;
690		}
691	
692	out:
(gdb) p params
$1 = 0x0

If can't found target, we should goto out

Signed-off-by: Wu Guanghao <wuguanghao3@huawei.com>
---
 libmultipath/devmapper.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
index 2507f77f..450b17ef 100644
--- a/libmultipath/devmapper.c
+++ b/libmultipath/devmapper.c
@@ -682,8 +682,8 @@ int dm_get_map(const char *name, unsigned long long *size, char **outparams)
        r = DMP_NOT_FOUND;
        /* Fetch 1st target */
        if (dm_get_next_target(dmt, NULL, &start, &length,
-                              &target_type, &params) != NULL)
-               /* more than one target */
+                              &target_type, &params) != NULL || !params)
+               /* more than one target or not found target */
                goto out;

        if (size)
--
2.27.0

--
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https://listman.redhat.com/mailman/listinfo/dm-devel


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [dm-devel] [PATCH]dm_get_map: fix segfault when can't found target
  2022-05-27  2:27 [dm-devel] [PATCH]dm_get_map: fix segfault when can't found target Wu Guanghao
@ 2022-05-27 19:35 ` Benjamin Marzinski
  2022-05-31  9:57   ` Martin Wilck
  0 siblings, 1 reply; 3+ messages in thread
From: Benjamin Marzinski @ 2022-05-27 19:35 UTC (permalink / raw)
  To: Wu Guanghao
  Cc: lixiaokeng, Christophe Varoqui, dm-devel mailing list,
	Martin Wilck, linfeilong

On Fri, May 27, 2022 at 10:27:37AM +0800, Wu Guanghao wrote:
> We got a segfault when we test multipath + iscsi.
> 
> (gdb) bt
> #0  __strlen_avx2 () at ../sysdeps/x86_64/multiarch/strlen-avx2.S:74
> #1  0x00007f694306cd23 in __GI___strdup (s=0x0) at strdup.c:41
> #2  0x00007f69433a147c in dm_get_map (name=0x55d4bc090320 "3600140537cde137ea8c43d8a971462c7",
>     size=size@entry=0x55d4bc0270d8, outparams=outparams@entry=0x7f6941add640) at devmapper.c:688
> #3  0x00007f69433cbbdf in update_multipath_table (mpp=mpp@entry=0x55d4bc026f30,
>     pathvec=pathvec@entry=0x55d4bc063990, flags=flags@entry=0) at structs_vec.c:426
> #4  0x00007f69433cbfe5 in update_multipath_strings (mpp=0x55d4bc026f30, pathvec=0x55d4bc063990)
>     at structs_vec.c:526
> #5  0x000055d4bb52e03e in check_path (vecs=0x55d4bbfad760, pp=0x7f692402d270, ticks=<optimized out>)
>     at main.c:2280
> #6  0x000055d4bb52f3e2 in checkerloop (ap=0x55d4bbfad760) at main.c:2542
> #7  0x00007f694305b3ba in start_thread (arg=<optimized out>) at pthread_create.c:443
> #8  0x00007f69430ddb40 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
> (gdb) f 2
> #2  0x00007f69433a147c in dm_get_map (name=0x55d4bc090320 "3600140537cde137ea8c43d8a971462c7",
>     size=size@entry=0x55d4bc0270d8, outparams=outparams@entry=0x7f6941add640) at devmapper.c:688
> 688			*outparams = strdup(params);
> (gdb) l
> 683			*size = length;
> 684	
> 685		if (!outparams)
> 686			r = DMP_OK;
> 687		else {
> 688			*outparams = strdup(params);
> 689			r = *outparams ? DMP_OK : DMP_ERR;
> 690		}
> 691	
> 692	out:
> (gdb) p params
> $1 = 0x0
> 
> If can't found target, we should goto out
> 
> Signed-off-by: Wu Guanghao <wuguanghao3@huawei.com>

Reviewed-by: Benjamin Marzinski <bmarzins@redhat.com>

> ---
>  libmultipath/devmapper.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
> index 2507f77f..450b17ef 100644
> --- a/libmultipath/devmapper.c
> +++ b/libmultipath/devmapper.c
> @@ -682,8 +682,8 @@ int dm_get_map(const char *name, unsigned long long *size, char **outparams)
>         r = DMP_NOT_FOUND;
>         /* Fetch 1st target */
>         if (dm_get_next_target(dmt, NULL, &start, &length,
> -                              &target_type, &params) != NULL)
> -               /* more than one target */
> +                              &target_type, &params) != NULL || !params)
> +               /* more than one target or not found target */
>                 goto out;
> 
>         if (size)
> --
> 2.27.0
--
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https://listman.redhat.com/mailman/listinfo/dm-devel


^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [dm-devel] [PATCH]dm_get_map: fix segfault when can't found target
  2022-05-27 19:35 ` Benjamin Marzinski
@ 2022-05-31  9:57   ` Martin Wilck
  0 siblings, 0 replies; 3+ messages in thread
From: Martin Wilck @ 2022-05-31  9:57 UTC (permalink / raw)
  To: Benjamin Marzinski, Wu Guanghao
  Cc: lixiaokeng, Christophe Varoqui, dm-devel mailing list, linfeilong

On Fri, 2022-05-27 at 14:35 -0500, Benjamin Marzinski wrote:
> On Fri, May 27, 2022 at 10:27:37AM +0800, Wu Guanghao wrote:
> > We got a segfault when we test multipath + iscsi.
> > 
> > (gdb) bt
> > #0  __strlen_avx2 () at ../sysdeps/x86_64/multiarch/strlen-
> > avx2.S:74
> > #1  0x00007f694306cd23 in __GI___strdup (s=0x0) at strdup.c:41
> > #2  0x00007f69433a147c in dm_get_map (name=0x55d4bc090320
> > "3600140537cde137ea8c43d8a971462c7",
> >     size=size@entry=0x55d4bc0270d8,
> > outparams=outparams@entry=0x7f6941add640) at devmapper.c:688
> > #3  0x00007f69433cbbdf in update_multipath_table
> > (mpp=mpp@entry=0x55d4bc026f30,
> >     pathvec=pathvec@entry=0x55d4bc063990, flags=flags@entry=0) at
> > structs_vec.c:426
> > #4  0x00007f69433cbfe5 in update_multipath_strings
> > (mpp=0x55d4bc026f30, pathvec=0x55d4bc063990)
> >     at structs_vec.c:526
> > #5  0x000055d4bb52e03e in check_path (vecs=0x55d4bbfad760,
> > pp=0x7f692402d270, ticks=<optimized out>)
> >     at main.c:2280
> > #6  0x000055d4bb52f3e2 in checkerloop (ap=0x55d4bbfad760) at
> > main.c:2542
> > #7  0x00007f694305b3ba in start_thread (arg=<optimized out>) at
> > pthread_create.c:443
> > #8  0x00007f69430ddb40 in clone3 () at
> > ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
> > (gdb) f 2
> > #2  0x00007f69433a147c in dm_get_map (name=0x55d4bc090320
> > "3600140537cde137ea8c43d8a971462c7",
> >     size=size@entry=0x55d4bc0270d8,
> > outparams=outparams@entry=0x7f6941add640) at devmapper.c:688
> > 688                     *outparams = strdup(params);
> > (gdb) l
> > 683                     *size = length;
> > 684     
> > 685             if (!outparams)
> > 686                     r = DMP_OK;
> > 687             else {
> > 688                     *outparams = strdup(params);
> > 689                     r = *outparams ? DMP_OK : DMP_ERR;
> > 690             }
> > 691     
> > 692     out:
> > (gdb) p params
> > $1 = 0x0
> > 
> > If can't found target, we should goto out
> > 
> > Signed-off-by: Wu Guanghao <wuguanghao3@huawei.com>
> 
> Reviewed-by: Benjamin Marzinski <bmarzins@redhat.com>

Reviewed-by: Martin Wilck <mwilck@suse.com>

Thanks! Note: We have two other callers of dm_get_next_target that
should add a similar check.

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^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-05-31  9:58 UTC | newest]

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2022-05-27  2:27 [dm-devel] [PATCH]dm_get_map: fix segfault when can't found target Wu Guanghao
2022-05-27 19:35 ` Benjamin Marzinski
2022-05-31  9:57   ` Martin Wilck

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