[PATCH -next] netlabel: Fix memory leak in netlbl_mgmt_add_common

Hulk Robot reported memory leak in netlbl_mgmt_add_common.
The problem is non-freed map in case of netlbl_domhsh_add() failed.

BUG: memory leak
unreferenced object 0xffff888100ab7080 (size 96):
  comm "syz-executor537", pid 360, jiffies 4294862456 (age 22.678s)
  hex dump (first 32 bytes):
    05 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    fe 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01  ................
  backtrace:
    [<0000000008b40026>] netlbl_mgmt_add_common.isra.0+0xb2a/0x1b40
    [<000000003be10950>] netlbl_mgmt_add+0x271/0x3c0
    [<00000000c70487ed>] genl_family_rcv_msg_doit.isra.0+0x20e/0x320
    [<000000001f2ff614>] genl_rcv_msg+0x2bf/0x4f0
    [<0000000089045792>] netlink_rcv_skb+0x134/0x3d0
    [<0000000020e96fdd>] genl_rcv+0x24/0x40
    [<0000000042810c66>] netlink_unicast+0x4a0/0x6a0
    [<000000002e1659f0>] netlink_sendmsg+0x789/0xc70
    [<000000006e43415f>] sock_sendmsg+0x139/0x170
    [<00000000680a73d7>] ____sys_sendmsg+0x658/0x7d0
    [<0000000065cbb8af>] ___sys_sendmsg+0xf8/0x170
    [<0000000019932b6c>] __sys_sendmsg+0xd3/0x190
    [<00000000643ac172>] do_syscall_64+0x37/0x90
    [<000000009b79d6dc>] entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: 63c416887437 ("netlabel: Add network address selectors to the NetLabel/LSM domain mapping")
Reported-by: Hulk Robot <redacted>
Signed-off-by: Liu Shixin <redacted>
---
 net/netlabel/netlabel_mgmt.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/net/netlabel/netlabel_mgmt.c b/net/netlabel/netlabel_mgmt.c
index e664ab990941..e7f00c0f441e 100644
--- a/net/netlabel/netlabel_mgmt.c
+++ b/net/netlabel/netlabel_mgmt.c

@@ -191,6 +191,12 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
 		entry->family = AF_INET;
 		entry->def.type = NETLBL_NLTYPE_ADDRSELECT;
 		entry->def.addrsel = addrmap;
+
+		ret_val = netlbl_domhsh_add(entry, audit_info);
+		if (ret_val != 0) {
+			kfree(map);
+			goto add_free_addrmap;
+		}
 #if IS_ENABLED(CONFIG_IPV6)
 	} else if (info->attrs[NLBL_MGMT_A_IPV6ADDR]) {
 		struct in6_addr *addr;

@@ -243,13 +249,19 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
 		entry->family = AF_INET6;
 		entry->def.type = NETLBL_NLTYPE_ADDRSELECT;
 		entry->def.addrsel = addrmap;
+
+		ret_val = netlbl_domhsh_add(entry, audit_info);
+		if (ret_val != 0) {
+			kfree(map);
+			goto add_free_addrmap;
+		}
 #endif /* IPv6 */
+	} else {
+		ret_val = netlbl_domhsh_add(entry, audit_info);
+		if (ret_val != 0)
+			goto add_free_addrmap;
 	}
 
-	ret_val = netlbl_domhsh_add(entry, audit_info);
-	if (ret_val != 0)
-		goto add_free_addrmap;
-
 	return 0;
 
 add_free_addrmap:

-- 
2.18.0.huawei.25

On Thu, Jun 10, 2021 at 9:31 AM Liu Shixin [off-list ref] wrote:

Hi Shixin,

I have a small suggestion about this patch: you can move the variable
map out of if/else if branches, like the following code snippet.

Be aware to assign the variable map to NULL at first. Then kfree in
the last else branch will do nothing.

I don't test the following diff, if there are any issues, please let me know.

diff --git a/net/netlabel/netlabel_mgmt.c b/net/netlabel/netlabel_mgmt.c
index ca52f5085989..1824bcd2272b 100644
--- a/net/netlabel/netlabel_mgmt.c
+++ b/net/netlabel/netlabel_mgmt.c

@@ -78,6 +78,7 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
 {
        int ret_val = -EINVAL;
        struct netlbl_domaddr_map *addrmap = NULL;
+       struct netlbl_domaddr4_map *map = NULL;
        struct cipso_v4_doi *cipsov4 = NULL;
 #if IS_ENABLED(CONFIG_IPV6)
        struct calipso_doi *calipso = NULL;

@@ -147,7 +148,6 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
        if (info->attrs[NLBL_MGMT_A_IPV4ADDR]) {
                struct in_addr *addr;
                struct in_addr *mask;
-               struct netlbl_domaddr4_map *map;

                addrmap = kzalloc(sizeof(*addrmap), GFP_KERNEL);
                if (addrmap == NULL) {

@@ -195,7 +195,6 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
        } else if (info->attrs[NLBL_MGMT_A_IPV6ADDR]) {
                struct in6_addr *addr;
                struct in6_addr *mask;
-               struct netlbl_domaddr6_map *map;

                addrmap = kzalloc(sizeof(*addrmap), GFP_KERNEL);
                if (addrmap == NULL) {

@@ -247,8 +246,10 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
        }

        ret_val = netlbl_domhsh_add(entry, audit_info);
-       if (ret_val != 0)
+       if (ret_val != 0) {
+               kfree(map);
                goto add_free_addrmap;
+       }

        return 0;

        return 0;

 add_free_addrmap:
--
2.18.0.huawei.25

On 2021/6/10 11:08, Dongliang Mu wrote:

The type of map can be struct netlbl_domaddr4_map or struct netlbl_domaddr6_map
under different conditions. It seems like I can't put them together simply.

Thanks,

quoted

        return 0;

 add_free_addrmap:
--
2.18.0.huawei.25

.

On Thu, Jun 10, 2021 at 6:45 PM Liu Shixin [off-list ref] wrote:

On 2021/6/10 11:08, Dongliang Mu wrote:

quoted

On Thu, Jun 10, 2021 at 9:31 AM Liu Shixin [off-list ref] wrote:

quoted

Hulk Robot reported memory leak in netlbl_mgmt_add_common.
The problem is non-freed map in case of netlbl_domhsh_add() failed.

BUG: memory leak
unreferenced object 0xffff888100ab7080 (size 96):
  comm "syz-executor537", pid 360, jiffies 4294862456 (age 22.678s)
  hex dump (first 32 bytes):
    05 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    fe 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01  ................
  backtrace:
    [<0000000008b40026>] netlbl_mgmt_add_common.isra.0+0xb2a/0x1b40
    [<000000003be10950>] netlbl_mgmt_add+0x271/0x3c0
    [<00000000c70487ed>] genl_family_rcv_msg_doit.isra.0+0x20e/0x320
    [<000000001f2ff614>] genl_rcv_msg+0x2bf/0x4f0
    [<0000000089045792>] netlink_rcv_skb+0x134/0x3d0
    [<0000000020e96fdd>] genl_rcv+0x24/0x40
    [<0000000042810c66>] netlink_unicast+0x4a0/0x6a0
    [<000000002e1659f0>] netlink_sendmsg+0x789/0xc70
    [<000000006e43415f>] sock_sendmsg+0x139/0x170
    [<00000000680a73d7>] ____sys_sendmsg+0x658/0x7d0
    [<0000000065cbb8af>] ___sys_sendmsg+0xf8/0x170
    [<0000000019932b6c>] __sys_sendmsg+0xd3/0x190
    [<00000000643ac172>] do_syscall_64+0x37/0x90
    [<000000009b79d6dc>] entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: 63c416887437 ("netlabel: Add network address selectors to the NetLabel/LSM domain mapping")
Reported-by: Hulk Robot <redacted>
Signed-off-by: Liu Shixin <redacted>
---
 net/netlabel/netlabel_mgmt.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/net/netlabel/netlabel_mgmt.c b/net/netlabel/netlabel_mgmt.c
index e664ab990941..e7f00c0f441e 100644
--- a/net/netlabel/netlabel_mgmt.c
+++ b/net/netlabel/netlabel_mgmt.c

@@ -191,6 +191,12 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
                entry->family = AF_INET;
                entry->def.type = NETLBL_NLTYPE_ADDRSELECT;
                entry->def.addrsel = addrmap;
+
+               ret_val = netlbl_domhsh_add(entry, audit_info);
+               if (ret_val != 0) {
+                       kfree(map);
+                       goto add_free_addrmap;
+               }
 #if IS_ENABLED(CONFIG_IPV6)
        } else if (info->attrs[NLBL_MGMT_A_IPV6ADDR]) {
                struct in6_addr *addr;

@@ -243,13 +249,19 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
                entry->family = AF_INET6;
                entry->def.type = NETLBL_NLTYPE_ADDRSELECT;
                entry->def.addrsel = addrmap;
+
+               ret_val = netlbl_domhsh_add(entry, audit_info);
+               if (ret_val != 0) {
+                       kfree(map);
+                       goto add_free_addrmap;
+               }
 #endif /* IPv6 */
+       } else {
+               ret_val = netlbl_domhsh_add(entry, audit_info);
+               if (ret_val != 0)
+                       goto add_free_addrmap;
        }

-       ret_val = netlbl_domhsh_add(entry, audit_info);
-       if (ret_val != 0)
-               goto add_free_addrmap;
-

Hi Shixin,

I have a small suggestion about this patch: you can move the variable
map out of if/else if branches, like the following code snippet.

Be aware to assign the variable map to NULL at first. Then kfree in
the last else branch will do nothing.

I don't test the following diff, if there are any issues, please let me know.

diff --git a/net/netlabel/netlabel_mgmt.c b/net/netlabel/netlabel_mgmt.c
index ca52f5085989..1824bcd2272b 100644
--- a/net/netlabel/netlabel_mgmt.c
+++ b/net/netlabel/netlabel_mgmt.c

@@ -78,6 +78,7 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
 {
        int ret_val = -EINVAL;
        struct netlbl_domaddr_map *addrmap = NULL;
+       struct netlbl_domaddr4_map *map = NULL;
        struct cipso_v4_doi *cipsov4 = NULL;
 #if IS_ENABLED(CONFIG_IPV6)
        struct calipso_doi *calipso = NULL;

@@ -147,7 +148,6 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
        if (info->attrs[NLBL_MGMT_A_IPV4ADDR]) {
                struct in_addr *addr;
                struct in_addr *mask;
-               struct netlbl_domaddr4_map *map;

                addrmap = kzalloc(sizeof(*addrmap), GFP_KERNEL);
                if (addrmap == NULL) {

@@ -195,7 +195,6 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
        } else if (info->attrs[NLBL_MGMT_A_IPV6ADDR]) {
                struct in6_addr *addr;
                struct in6_addr *mask;
-               struct netlbl_domaddr6_map *map;

                addrmap = kzalloc(sizeof(*addrmap), GFP_KERNEL);
                if (addrmap == NULL) {

@@ -247,8 +246,10 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
        }

        ret_val = netlbl_domhsh_add(entry, audit_info);
-       if (ret_val != 0)
+       if (ret_val != 0) {
+               kfree(map);
                goto add_free_addrmap;
+       }

        return 0;

The type of map can be struct netlbl_domaddr4_map or struct netlbl_domaddr6_map
under different conditions. It seems like I can't put them together simply.

Yes, you're right. It takes more code changes to handle different
types. I choose to use the generic void * pointer.

The advantage of the diff below is to improve its maintainability of
error handling. I add one additional label: add_free_map to handle the
deallocation of map.

Note that, I did not test this diff. It is only used for
clarification. And maybe the compiler complains about the usage of
void * pointer.

diff --git a/net/netlabel/netlabel_mgmt.c b/net/netlabel/netlabel_mgmt.c
index ca52f5085989..38edf170b109 100644
--- a/net/netlabel/netlabel_mgmt.c
+++ b/net/netlabel/netlabel_mgmt.c

@@ -78,6 +78,7 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
 {
        int ret_val = -EINVAL;
        struct netlbl_domaddr_map *addrmap = NULL;
+       void *map = NULL;
        struct cipso_v4_doi *cipsov4 = NULL;
 #if IS_ENABLED(CONFIG_IPV6)
        struct calipso_doi *calipso = NULL;

@@ -147,7 +148,6 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
        if (info->attrs[NLBL_MGMT_A_IPV4ADDR]) {
                struct in_addr *addr;
                struct in_addr *mask;
-               struct netlbl_domaddr4_map *map;

                addrmap = kzalloc(sizeof(*addrmap), GFP_KERNEL);
                if (addrmap == NULL) {

@@ -170,7 +170,7 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
                addr = nla_data(info->attrs[NLBL_MGMT_A_IPV4ADDR]);
                mask = nla_data(info->attrs[NLBL_MGMT_A_IPV4MASK]);

-               map = kzalloc(sizeof(*map), GFP_KERNEL);
+               map = kzalloc(sizeof(struct netlbl_domaddr4_map), GFP_KERNEL);
                if (map == NULL) {
                        ret_val = -ENOMEM;
                        goto add_free_addrmap;

@@ -183,10 +183,8 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
                        map->def.cipso = cipsov4;

                ret_val = netlbl_af4list_add(&map->list, &addrmap->list4);
-               if (ret_val != 0) {
-                       kfree(map);
-                       goto add_free_addrmap;
-               }
+               if (ret_val != 0)
+                       goto add_free_map;

                entry->family = AF_INET;
                entry->def.type = NETLBL_NLTYPE_ADDRSELECT;

@@ -218,7 +216,7 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
                addr = nla_data(info->attrs[NLBL_MGMT_A_IPV6ADDR]);
                mask = nla_data(info->attrs[NLBL_MGMT_A_IPV6MASK]);

-               map = kzalloc(sizeof(*map), GFP_KERNEL);
+               map = kzalloc(sizeof(struct netlbl_domaddr6_map), GFP_KERNEL);
                if (map == NULL) {
                        ret_val = -ENOMEM;
                        goto add_free_addrmap;

@@ -235,10 +233,8 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
                        map->def.calipso = calipso;

                ret_val = netlbl_af6list_add(&map->list, &addrmap->list6);
-               if (ret_val != 0) {
-                       kfree(map);
-                       goto add_free_addrmap;
-               }
+               if (ret_val != 0)
+                       goto add_free_map;

                entry->family = AF_INET6;
                entry->def.type = NETLBL_NLTYPE_ADDRSELECT;

@@ -248,10 +244,12 @@ static int netlbl_mgmt_add_common(struct genl_info *info,

        ret_val = netlbl_domhsh_add(entry, audit_info);
        if (ret_val != 0)
-               goto add_free_addrmap;
+               goto add_free_map;

        return 0;

+add_free_map:
+       kfree(map);
 add_free_addrmap:
        kfree(addrmap);
 add_doi_put_def:

Thanks,

quoted

quoted

        return 0;

 add_free_addrmap:
--
2.18.0.huawei.25

.

On Wed, Jun 9, 2021 at 9:29 PM Liu Shixin [off-list ref] wrote:

Thanks for the report and a fix, although I think there may be a
simpler fix that results in less code duplication; some quick pseudo
code below:

  int netlbl_mgmt_add_common(...)
  {
     void *map_p = NULL;

     if (NLBL_MGMT_A_IPV4ADDR) {
       struct netlbl_domaddr4_map *map;
       map_p = map;

     } else if (NLBL_MGMT_A_IPV6ADDR) {
       struct netlbl_domaddr4_map *map;
       map_p = map;
    }

  add_free_addrmap:
    kfree(map_p);
    kfree(addrmap);
  }

... this approach would even simplify the error handling after the
netlbl_af{4,6}list_add() calls a bit too (you could jump straight to
add_free_addrmap).

-- 
paul moore
www.paul-moore.com

On Fri, Jun 11, 2021 at 7:43 AM Paul Moore [off-list ref] wrote:

On Wed, Jun 9, 2021 at 9:29 PM Liu Shixin [off-list ref] wrote:

quoted

Hulk Robot reported memory leak in netlbl_mgmt_add_common.
The problem is non-freed map in case of netlbl_domhsh_add() failed.

BUG: memory leak
unreferenced object 0xffff888100ab7080 (size 96):
  comm "syz-executor537", pid 360, jiffies 4294862456 (age 22.678s)
  hex dump (first 32 bytes):
    05 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    fe 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01  ................
  backtrace:
    [<0000000008b40026>] netlbl_mgmt_add_common.isra.0+0xb2a/0x1b40
    [<000000003be10950>] netlbl_mgmt_add+0x271/0x3c0
    [<00000000c70487ed>] genl_family_rcv_msg_doit.isra.0+0x20e/0x320
    [<000000001f2ff614>] genl_rcv_msg+0x2bf/0x4f0
    [<0000000089045792>] netlink_rcv_skb+0x134/0x3d0
    [<0000000020e96fdd>] genl_rcv+0x24/0x40
    [<0000000042810c66>] netlink_unicast+0x4a0/0x6a0
    [<000000002e1659f0>] netlink_sendmsg+0x789/0xc70
    [<000000006e43415f>] sock_sendmsg+0x139/0x170
    [<00000000680a73d7>] ____sys_sendmsg+0x658/0x7d0
    [<0000000065cbb8af>] ___sys_sendmsg+0xf8/0x170
    [<0000000019932b6c>] __sys_sendmsg+0xd3/0x190
    [<00000000643ac172>] do_syscall_64+0x37/0x90
    [<000000009b79d6dc>] entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: 63c416887437 ("netlabel: Add network address selectors to the NetLabel/LSM domain mapping")
Reported-by: Hulk Robot <redacted>
Signed-off-by: Liu Shixin <redacted>
---
 net/netlabel/netlabel_mgmt.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/net/netlabel/netlabel_mgmt.c b/net/netlabel/netlabel_mgmt.c
index e664ab990941..e7f00c0f441e 100644
--- a/net/netlabel/netlabel_mgmt.c
+++ b/net/netlabel/netlabel_mgmt.c

@@ -191,6 +191,12 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
                entry->family = AF_INET;
                entry->def.type = NETLBL_NLTYPE_ADDRSELECT;
                entry->def.addrsel = addrmap;
+
+               ret_val = netlbl_domhsh_add(entry, audit_info);
+               if (ret_val != 0) {
+                       kfree(map);
+                       goto add_free_addrmap;
+               }
 #if IS_ENABLED(CONFIG_IPV6)
        } else if (info->attrs[NLBL_MGMT_A_IPV6ADDR]) {
                struct in6_addr *addr;

@@ -243,13 +249,19 @@ static int netlbl_mgmt_add_common(struct genl_info *info,
                entry->family = AF_INET6;
                entry->def.type = NETLBL_NLTYPE_ADDRSELECT;
                entry->def.addrsel = addrmap;
+
+               ret_val = netlbl_domhsh_add(entry, audit_info);
+               if (ret_val != 0) {
+                       kfree(map);
+                       goto add_free_addrmap;
+               }
 #endif /* IPv6 */
+       } else {
+               ret_val = netlbl_domhsh_add(entry, audit_info);
+               if (ret_val != 0)
+                       goto add_free_addrmap;
        }

-       ret_val = netlbl_domhsh_add(entry, audit_info);
-       if (ret_val != 0)
-               goto add_free_addrmap;
-
        return 0;

Thanks for the report and a fix, although I think there may be a
simpler fix that results in less code duplication; some quick pseudo
code below:

  int netlbl_mgmt_add_common(...)
  {
     void *map_p = NULL;

     if (NLBL_MGMT_A_IPV4ADDR) {
       struct netlbl_domaddr4_map *map;
       map_p = map;

It's better to use a separate map_p pointer, not like the draft patch
I sent yesterday.

     } else if (NLBL_MGMT_A_IPV6ADDR) {
       struct netlbl_domaddr4_map *map;
       map_p = map;
    }

  add_free_addrmap:
    kfree(map_p);
    kfree(addrmap);
  }

Simple comment here: we should separate kfree(map_p) and
kfree(addrmap) into different goto labels, just like the draft patch I
sent yesterday.

... this approach would even simplify the error handling after the
netlbl_af{4,6}list_add() calls a bit too (you could jump straight to
add_free_addrmap).

--
paul moore
www.paul-moore.com