memory leak in tipc_group_create_member

memory leak in tipc_group_create_member

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    a9815a4f Merge branch 'x86-urgent-for-linus' of git://git...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12a6dbf0600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=37c48fb52e3789e6
dashboard link: https://syzkaller.appspot.com/bug?extid=f95d90c454864b3b5bc9
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13be3ecc600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11c992b4600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+f95d90c454864b3b5bc9@syzkaller.appspotmail.com

executing program
BUG: memory leak
unreferenced object 0xffff888122bca200 (size 128):
   comm "syz-executor232", pid 7065, jiffies 4294943817 (age 8.880s)
   hex dump (first 32 bytes):
     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
     00 00 00 00 00 00 00 00 18 a2 bc 22 81 88 ff ff  ..........."....
   backtrace:
     [<000000005bada299>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:43 [inline]
     [<000000005bada299>] slab_post_alloc_hook mm/slab.h:522 [inline]
     [<000000005bada299>] slab_alloc mm/slab.c:3319 [inline]
     [<000000005bada299>] kmem_cache_alloc_trace+0x145/0x2c0 mm/slab.c:3548
     [<00000000e7bcdc9f>] kmalloc include/linux/slab.h:552 [inline]
     [<00000000e7bcdc9f>] kzalloc include/linux/slab.h:748 [inline]
     [<00000000e7bcdc9f>] tipc_group_create_member+0x3c/0x190  
net/tipc/group.c:306
     [<0000000005f56f40>] tipc_group_add_member+0x34/0x40  
net/tipc/group.c:327
     [<0000000044406683>] tipc_nametbl_build_group+0x9b/0xf0  
net/tipc/name_table.c:600
     [<000000009f71e803>] tipc_sk_join net/tipc/socket.c:2901 [inline]
     [<000000009f71e803>] tipc_setsockopt+0x170/0x490 net/tipc/socket.c:3006
     [<000000007f61cbc2>] __sys_setsockopt+0x10f/0x220 net/socket.c:2084
     [<00000000cc630372>] __do_sys_setsockopt net/socket.c:2100 [inline]
     [<00000000cc630372>] __se_sys_setsockopt net/socket.c:2097 [inline]
     [<00000000cc630372>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2097
     [<00000000ec30be33>] do_syscall_64+0x76/0x1a0  
arch/x86/entry/common.c:296
     [<00000000271be3e6>] entry_SYSCALL_64_after_hwframe+0x44/0xa9



---
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See https://goo.gl/tpsmEJ for more information about syzbot.
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syzbot can test patches for this bug, for details see:
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Re: memory leak in tipc_group_create_member

[Ying Xue]

On 8/2/19 3:44 PM, Hillf Danton wrote:
> 
> On Thu, 01 Aug 2019 19:38:06 -0700
>> Hello,
>>
>> syzbot found the following crash on:
>>
>> HEAD commit:    a9815a4f Merge branch 'x86-urgent-for-linus' of git://git...
>> git tree:       upstream
>> console output: https://syzkaller.appspot.com/x/log.txt?x=12a6dbf0600000
>> kernel config:  https://syzkaller.appspot.com/x/.config?x=37c48fb52e3789e6
>> dashboard link: https://syzkaller.appspot.com/bug?extid=f95d90c454864b3b5bc9
>> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
>> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13be3ecc600000
>> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11c992b4600000
>>
>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> Reported-by: syzbot+f95d90c454864b3b5bc9@syzkaller.appspotmail.com
>>
>> executing program
>> BUG: memory leak
>> unreferenced object 0xffff888122bca200 (size 128):
>>    comm "syz-executor232", pid 7065, jiffies 4294943817 (age 8.880s)
>>    hex dump (first 32 bytes):
>>      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>      00 00 00 00 00 00 00 00 18 a2 bc 22 81 88 ff ff  ..........."....
>>    backtrace:
>>      [<000000005bada299>] kmemleak_alloc_recursive  include/linux/kmemleak.h:43 [inline]
>>      [<000000005bada299>] slab_post_alloc_hook mm/slab.h:522 [inline]
>>      [<000000005bada299>] slab_alloc mm/slab.c:3319 [inline]
>>      [<000000005bada299>] kmem_cache_alloc_trace+0x145/0x2c0 mm/slab.c:3548
>>      [<00000000e7bcdc9f>] kmalloc include/linux/slab.h:552 [inline]
>>      [<00000000e7bcdc9f>] kzalloc include/linux/slab.h:748 [inline]
>>      [<00000000e7bcdc9f>] tipc_group_create_member+0x3c/0x190  net/tipc/group.c:306
>>      [<0000000005f56f40>] tipc_group_add_member+0x34/0x40  net/tipc/group.c:327
>>      [<0000000044406683>] tipc_nametbl_build_group+0x9b/0xf0  net/tipc/name_table.c:600
>>      [<000000009f71e803>] tipc_sk_join net/tipc/socket.c:2901 [inline]
>>      [<000000009f71e803>] tipc_setsockopt+0x170/0x490 net/tipc/socket.c:3006
>>      [<000000007f61cbc2>] __sys_setsockopt+0x10f/0x220 net/socket.c:2084
>>      [<00000000cc630372>] __do_sys_setsockopt net/socket.c:2100 [inline]
>>      [<00000000cc630372>] __se_sys_setsockopt net/socket.c:2097 [inline]
>>      [<00000000cc630372>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2097
>>      [<00000000ec30be33>] do_syscall_64+0x76/0x1a0  arch/x86/entry/common.c:296
>>      [<00000000271be3e6>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>

Acked-by: Ying Xue <ying.xue@windriver.com>

>  
> --- a/net/tipc/group.c
> +++ b/net/tipc/group.c
> @@ -273,7 +273,7 @@ static struct tipc_member *tipc_group_fi
>  	return NULL;
>  }
>  
> -static void tipc_group_add_to_tree(struct tipc_group *grp,
> +static struct tipc_member *tipc_group_add_to_tree(struct tipc_group *grp,
>  				   struct tipc_member *m)
>  {
>  	u64 nkey, key = (u64)m->node << 32 | m->port;
> @@ -282,7 +282,6 @@ static void tipc_group_add_to_tree(struc
>  
>  	n = &grp->members.rb_node;
>  	while (*n) {
> -		tmp = container_of(*n, struct tipc_member, tree_node);
>  		parent = *n;
>  		tmp = container_of(parent, struct tipc_member, tree_node);
>  		nkey = (u64)tmp->node << 32 | tmp->port;
> @@ -291,17 +290,18 @@ static void tipc_group_add_to_tree(struc
>  		else if (key > nkey)
>  			n = &(*n)->rb_right;
>  		else
> -			return;
> +			return tmp;
>  	}
>  	rb_link_node(&m->tree_node, parent, n);
>  	rb_insert_color(&m->tree_node, &grp->members);
> +	return m;
>  }
>  
>  static struct tipc_member *tipc_group_create_member(struct tipc_group *grp,
>  						    u32 node, u32 port,
>  						    u32 instance, int state)
>  {
> -	struct tipc_member *m;
> +	struct tipc_member *m, *n;
>  
>  	m = kzalloc(sizeof(*m), GFP_ATOMIC);
>  	if (!m)
> @@ -315,10 +315,14 @@ static struct tipc_member *tipc_group_cr
>  	m->instance = instance;
>  	m->bc_acked = grp->bc_snd_nxt - 1;
>  	grp->member_cnt++;
> -	tipc_group_add_to_tree(grp, m);
> -	tipc_nlist_add(&grp->dests, m->node);
> -	m->state = state;
> -	return m;
> +	n = tipc_group_add_to_tree(grp, m);
> +	if (n == m) {
> +		tipc_nlist_add(&grp->dests, m->node);
> +		m->state = state;
> +	} else {
> +		kfree(m);
> +	}
> +	return n;
>  }
>  
>  void tipc_group_add_member(struct tipc_group *grp, u32 node,
> --
> 
> 

[Linux-kernel-mentees] [PATCH net] tipc: Fix memory leak in tipc_group_create_member()

[Peilin Ye]

tipc_group_add_to_tree() returns silently if `key` matches `nkey` of an
existing node, causing tipc_group_create_member() to leak memory. Let
tipc_group_add_to_tree() return an error in such a case, so that
tipc_group_create_member() can handle it properly.

Fixes: 75da2163dbb6 ("tipc: introduce communication groups")
Reported-and-tested-by: syzbot+f95d90c454864b3b5bc9@syzkaller.appspotmail.com
Cc: Hillf Danton <hdanton@sina.com>
Link: https://syzkaller.appspot.com/bug?id=048390604fe1b60df34150265479202f10e13aff
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
Decoded syzbot reproducer in pseudo-C:

	fd0 = socket(AF_TIPC, SOCK_DGRAM, 0);

	sockaddr_tipc.family = AF_TIPC;
	sockaddr_tipc.addrtype = TIPC_ADDR_NAMESEQ;
	sockaddr_tipc.scope = 0;
	sockaddr_tipc.addr.namesq.type = TIPC_RESERVED_TYPES + 1;
	bind(fd0, &sockaddr_tipc, sizeof(sockaddr_tipc));

	tipc_group_req0.type = TIPC_RESERVED_TYPES + 1;
	setsockopt(fd0, SOL_TIPC, TIPC_GROUP_JOIN, &tipc_group_req0, sizeof(tipc_group_req0));

	fd1 = socket(AF_TIPC, SOCK_STREAM, 0);

	tipc_group_req1.type = TIPC_RESERVED_TYPES + 1;
	tipc_group_req1.scope = TIPC_CLUSTER_SCOPE;
	setsockopt(fd1, SOL_TIPC, TIPC_GROUP_JOIN, &tipc_group_req1, sizeof(tipc_group_req1));

 net/tipc/group.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/net/tipc/group.c b/net/tipc/group.c
index 588c2d2b0c69..553cf08b4d76 100644
--- a/net/tipc/group.c
+++ b/net/tipc/group.c
@@ -273,8 +273,8 @@ static struct tipc_member *tipc_group_find_node(struct tipc_group *grp,
 	return NULL;
 }
 
-static void tipc_group_add_to_tree(struct tipc_group *grp,
-				   struct tipc_member *m)
+static int tipc_group_add_to_tree(struct tipc_group *grp,
+				  struct tipc_member *m)
 {
 	u64 nkey, key = (u64)m->node << 32 | m->port;
 	struct rb_node **n, *parent = NULL;
@@ -291,10 +291,11 @@ static void tipc_group_add_to_tree(struct tipc_group *grp,
 		else if (key > nkey)
 			n = &(*n)->rb_right;
 		else
-			return;
+			return -1;
 	}
 	rb_link_node(&m->tree_node, parent, n);
 	rb_insert_color(&m->tree_node, &grp->members);
+	return 0;
 }
 
 static struct tipc_member *tipc_group_create_member(struct tipc_group *grp,
@@ -302,6 +303,7 @@ static struct tipc_member *tipc_group_create_member(struct tipc_group *grp,
 						    u32 instance, int state)
 {
 	struct tipc_member *m;
+	int ret;
 
 	m = kzalloc(sizeof(*m), GFP_ATOMIC);
 	if (!m)
@@ -314,8 +316,12 @@ static struct tipc_member *tipc_group_create_member(struct tipc_group *grp,
 	m->port = port;
 	m->instance = instance;
 	m->bc_acked = grp->bc_snd_nxt - 1;
+	ret = tipc_group_add_to_tree(grp, m);
+	if (ret < 0) {
+		kfree(m);
+		return NULL;
+	}
 	grp->member_cnt++;
-	tipc_group_add_to_tree(grp, m);
 	tipc_nlist_add(&grp->dests, m->node);
 	m->state = state;
 	return m;
-- 
2.25.1

Re: [Linux-kernel-mentees] [PATCH net] tipc: Fix memory leak in tipc_group_create_member()

[David Miller]

From: Peilin Ye <yepeilin.cs@gmail.com>
Date: Sat, 12 Sep 2020 06:22:30 -0400

> @@ -291,10 +291,11 @@ static void tipc_group_add_to_tree(struct tipc_group *grp,
>  		else if (key > nkey)
>  			n = &(*n)->rb_right;
>  		else
> -			return;
> +			return -1;

Use a real error code like "-EEXIST", thank you.

Re: [Linux-kernel-mentees] [PATCH net] tipc: Fix memory leak in tipc_group_create_member()

[Peilin Ye]

On Sat, Sep 12, 2020 at 06:23:36PM -0700, David Miller wrote:
> From: Peilin Ye <yepeilin.cs@gmail.com>
> Date: Sat, 12 Sep 2020 06:22:30 -0400
> 
> > @@ -291,10 +291,11 @@ static void tipc_group_add_to_tree(struct tipc_group *grp,
> >  		else if (key > nkey)
> >  			n = &(*n)->rb_right;
> >  		else
> > -			return;
> > +			return -1;
> 
> Use a real error code like "-EEXIST", thank you.

Ah, I'll fix it in v2 soon, sorry about that. I saw another function in
this file returning -1.

Peilin Ye

[Linux-kernel-mentees] [PATCH net v2] tipc: Fix memory leak in tipc_group_create_member()

[Peilin Ye]

tipc_group_add_to_tree() returns silently if `key` matches `nkey` of an
existing node, causing tipc_group_create_member() to leak memory. Let
tipc_group_add_to_tree() return an error in such a case, so that
tipc_group_create_member() can handle it properly.

Fixes: 75da2163dbb6 ("tipc: introduce communication groups")
Reported-and-tested-by: syzbot+f95d90c454864b3b5bc9@syzkaller.appspotmail.com
Cc: Hillf Danton <hdanton@sina.com>
Link: https://syzkaller.appspot.com/bug?id=048390604fe1b60df34150265479202f10e13aff
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
Change in v2:
    - let tipc_group_add_to_tree() return a real error code instead of -1.
      (Suggested by David Miller <davem@davemloft.net>)

 net/tipc/group.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/net/tipc/group.c b/net/tipc/group.c
index 588c2d2b0c69..b1fcd2ad5ecf 100644
--- a/net/tipc/group.c
+++ b/net/tipc/group.c
@@ -273,8 +273,8 @@ static struct tipc_member *tipc_group_find_node(struct tipc_group *grp,
 	return NULL;
 }
 
-static void tipc_group_add_to_tree(struct tipc_group *grp,
-				   struct tipc_member *m)
+static int tipc_group_add_to_tree(struct tipc_group *grp,
+				  struct tipc_member *m)
 {
 	u64 nkey, key = (u64)m->node << 32 | m->port;
 	struct rb_node **n, *parent = NULL;
@@ -291,10 +291,11 @@ static void tipc_group_add_to_tree(struct tipc_group *grp,
 		else if (key > nkey)
 			n = &(*n)->rb_right;
 		else
-			return;
+			return -EEXIST;
 	}
 	rb_link_node(&m->tree_node, parent, n);
 	rb_insert_color(&m->tree_node, &grp->members);
+	return 0;
 }
 
 static struct tipc_member *tipc_group_create_member(struct tipc_group *grp,
@@ -302,6 +303,7 @@ static struct tipc_member *tipc_group_create_member(struct tipc_group *grp,
 						    u32 instance, int state)
 {
 	struct tipc_member *m;
+	int ret;
 
 	m = kzalloc(sizeof(*m), GFP_ATOMIC);
 	if (!m)
@@ -314,8 +316,12 @@ static struct tipc_member *tipc_group_create_member(struct tipc_group *grp,
 	m->port = port;
 	m->instance = instance;
 	m->bc_acked = grp->bc_snd_nxt - 1;
+	ret = tipc_group_add_to_tree(grp, m);
+	if (ret < 0) {
+		kfree(m);
+		return NULL;
+	}
 	grp->member_cnt++;
-	tipc_group_add_to_tree(grp, m);
 	tipc_nlist_add(&grp->dests, m->node);
 	m->state = state;
 	return m;
-- 
2.25.1

Re: [Linux-kernel-mentees] [PATCH net v2] tipc: Fix memory leak in tipc_group_create_member()

[David Miller]

From: Peilin Ye <yepeilin.cs@gmail.com>
Date: Sun, 13 Sep 2020 04:06:05 -0400

> tipc_group_add_to_tree() returns silently if `key` matches `nkey` of an
> existing node, causing tipc_group_create_member() to leak memory. Let
> tipc_group_add_to_tree() return an error in such a case, so that
> tipc_group_create_member() can handle it properly.
> 
> Fixes: 75da2163dbb6 ("tipc: introduce communication groups")
> Reported-and-tested-by: syzbot+f95d90c454864b3b5bc9@syzkaller.appspotmail.com
> Cc: Hillf Danton <hdanton@sina.com>
> Link: https://syzkaller.appspot.com/bug?id=048390604fe1b60df34150265479202f10e13aff
> Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
> ---
> Change in v2:
>     - let tipc_group_add_to_tree() return a real error code instead of -1.
>       (Suggested by David Miller <davem@davemloft.net>)

Applied and queued up for -stable, thank you.