Messages in this thread Patch in this message | | | From | Shigeru Yoshida <> | Subject | [PATCH net v2] tipc: Fix uninit-value access in tipc_nl_node_reset_link_stats() | Date | Sat, 21 Oct 2023 01:34:15 +0900 |
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syzbot reported the following uninit-value access issue:
===================================================== BUG: KMSAN: uninit-value in strlen lib/string.c:418 [inline] BUG: KMSAN: uninit-value in strstr+0xb8/0x2f0 lib/string.c:756 strlen lib/string.c:418 [inline] strstr+0xb8/0x2f0 lib/string.c:756 tipc_nl_node_reset_link_stats+0x3ea/0xb50 net/tipc/node.c:2595 genl_family_rcv_msg_doit net/netlink/genetlink.c:971 [inline] genl_family_rcv_msg net/netlink/genetlink.c:1051 [inline] genl_rcv_msg+0x11ec/0x1290 net/netlink/genetlink.c:1066 netlink_rcv_skb+0x371/0x650 net/netlink/af_netlink.c:2545 genl_rcv+0x40/0x60 net/netlink/genetlink.c:1075 netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline] netlink_unicast+0xf47/0x1250 net/netlink/af_netlink.c:1368 netlink_sendmsg+0x1238/0x13d0 net/netlink/af_netlink.c:1910 sock_sendmsg_nosec net/socket.c:730 [inline] sock_sendmsg net/socket.c:753 [inline] ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2541 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2595 __sys_sendmsg net/socket.c:2624 [inline] __do_sys_sendmsg net/socket.c:2633 [inline] __se_sys_sendmsg net/socket.c:2631 [inline] __x64_sys_sendmsg+0x307/0x490 net/socket.c:2631 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd
Uninit was created at: slab_post_alloc_hook+0x12f/0xb70 mm/slab.h:767 slab_alloc_node mm/slub.c:3478 [inline] kmem_cache_alloc_node+0x577/0xa80 mm/slub.c:3523 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:559 __alloc_skb+0x318/0x740 net/core/skbuff.c:650 alloc_skb include/linux/skbuff.h:1286 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1214 [inline] netlink_sendmsg+0xb34/0x13d0 net/netlink/af_netlink.c:1885 sock_sendmsg_nosec net/socket.c:730 [inline] sock_sendmsg net/socket.c:753 [inline] ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2541 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2595 __sys_sendmsg net/socket.c:2624 [inline] __do_sys_sendmsg net/socket.c:2633 [inline] __se_sys_sendmsg net/socket.c:2631 [inline] __x64_sys_sendmsg+0x307/0x490 net/socket.c:2631 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd
Link names must be null-terminated strings. If a link name which is not null-terminated is passed through netlink, strstr() and similar functions can cause buffer overrun. This causes the above issue.
This patch resolves the issue by using nla_strscpy() to ensure the link name is null-terminated.
Fixes: ae36342b50a9 ("tipc: add link stat reset to new netlink api") Reported-and-tested-by: syzbot+5138ca807af9d2b42574@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=5138ca807af9d2b42574 Signed-off-by: Shigeru Yoshida <syoshida@redhat.com> --- v1->v2: - Use nla_strscpy() - Fix similar bugs in other functions other than syzbot reported --- net/tipc/node.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/net/tipc/node.c b/net/tipc/node.c index 3105abe97bb9..2121908e56c1 100644 --- a/net/tipc/node.c +++ b/net/tipc/node.c @@ -2419,7 +2419,7 @@ int tipc_nl_node_set_link(struct sk_buff *skb, struct genl_info *info) int err; int res = 0; int bearer_id; - char *name; + char name[TIPC_MAX_LINK_NAME]; struct tipc_link *link; struct tipc_node *node; struct sk_buff_head xmitq; @@ -2440,7 +2440,7 @@ int tipc_nl_node_set_link(struct sk_buff *skb, struct genl_info *info) if (!attrs[TIPC_NLA_LINK_NAME]) return -EINVAL; - name = nla_data(attrs[TIPC_NLA_LINK_NAME]); + nla_strscpy(name, attrs[TIPC_NLA_LINK_NAME], TIPC_MAX_LINK_NAME); if (strcmp(name, tipc_bclink_name) == 0) return tipc_nl_bc_link_set(net, attrs); @@ -2500,7 +2500,7 @@ int tipc_nl_node_get_link(struct sk_buff *skb, struct genl_info *info) struct net *net = genl_info_net(info); struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1]; struct tipc_nl_msg msg; - char *name; + char name[TIPC_MAX_LINK_NAME]; int err; msg.portid = info->snd_portid; @@ -2518,7 +2518,7 @@ int tipc_nl_node_get_link(struct sk_buff *skb, struct genl_info *info) if (!attrs[TIPC_NLA_LINK_NAME]) return -EINVAL; - name = nla_data(attrs[TIPC_NLA_LINK_NAME]); + nla_strscpy(name, attrs[TIPC_NLA_LINK_NAME], TIPC_MAX_LINK_NAME); msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL); if (!msg.skb) @@ -2563,7 +2563,7 @@ int tipc_nl_node_get_link(struct sk_buff *skb, struct genl_info *info) int tipc_nl_node_reset_link_stats(struct sk_buff *skb, struct genl_info *info) { int err; - char *link_name; + char link_name[TIPC_MAX_LINK_NAME]; unsigned int bearer_id; struct tipc_link *link; struct tipc_node *node; @@ -2584,7 +2584,7 @@ int tipc_nl_node_reset_link_stats(struct sk_buff *skb, struct genl_info *info) if (!attrs[TIPC_NLA_LINK_NAME]) return -EINVAL; - link_name = nla_data(attrs[TIPC_NLA_LINK_NAME]); + nla_strscpy(link_name, attrs[TIPC_NLA_LINK_NAME], TIPC_MAX_LINK_NAME); err = -EINVAL; if (!strcmp(link_name, tipc_bclink_name)) { -- 2.41.0
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