| Message ID | 20231013070408.1979343-1-make_ruc2021@163.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | tipc: Fix uninit-value access in tipc_nl_node_get_link() | expand |
On 13/10/2023 08:04, Ma Ke wrote: > Names must be null-terminated strings. If a name which is not > null-terminated is passed through netlink, strstr() and similar > functions can cause buffer overrun. This patch fixes this issue > by returning -EINVAL if a non-null-terminated name is passed. > > Signed-off-by: Ma Ke <make_ruc2021@163.com> > --- > net/tipc/node.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/tipc/node.c b/net/tipc/node.c > index 3105abe97bb9..a02bcd7e07d3 100644 > --- a/net/tipc/node.c > +++ b/net/tipc/node.c > @@ -2519,6 +2519,9 @@ int tipc_nl_node_get_link(struct sk_buff *skb, struct genl_info *info) > return -EINVAL; > > name = nla_data(attrs[TIPC_NLA_LINK_NAME]); > + if (name[strnlen(name, > + nla_len(attrs[TIPC_NLA_LINK_NAME]))] != '\0') > + return -EINVAL; The better choice would be to use strncmp() with limit of TIPC_MAX_LINK_NAME in tipc_node_find_by_name(). This patch fixes tipc_nl_node_get_link(), but the same pattern is used in tipc_nl_node_set_link() and tipc_nl_node_reset_link_stats(), these functions also need improvements. Changes to strncmp() and strnstr() will fix all spots. > > msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL); > if (!msg.skb)
Ma Ke <make_ruc2021@163.com> wrote: > Names must be null-terminated strings. If a name which is not > null-terminated is passed through netlink, strstr() and similar > functions can cause buffer overrun. This patch fixes this issue > by returning -EINVAL if a non-null-terminated name is passed. > > Signed-off-by: Ma Ke <make_ruc2021@163.com> > --- > net/tipc/node.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/tipc/node.c b/net/tipc/node.c > index 3105abe97bb9..a02bcd7e07d3 100644 > --- a/net/tipc/node.c > +++ b/net/tipc/node.c > @@ -2519,6 +2519,9 @@ int tipc_nl_node_get_link(struct sk_buff *skb, struct genl_info *info) > return -EINVAL; > > name = nla_data(attrs[TIPC_NLA_LINK_NAME]); > + if (name[strnlen(name, > + nla_len(attrs[TIPC_NLA_LINK_NAME]))] != '\0') > + return -EINVAL; If the existing userspace is passing 0-terminated strings it would be better to fix the policy (tipc_nl_link_policy) instead (and set NLA_NUL_STRING). And if not, above change breaks userspace.
On Fri, 13 Oct 2023 15:04:08 +0800 Ma Ke wrote: > Names must be null-terminated strings. If a name which is not > null-terminated is passed through netlink, strstr() and similar > functions can cause buffer overrun. This patch fixes this issue > by returning -EINVAL if a non-null-terminated name is passed. > > Signed-off-by: Ma Ke <make_ruc2021@163.com> You have now sent 14 incorrect fixes to Linux networking. And not a single correct one. I would like to politely ask you to stop.
diff --git a/net/tipc/node.c b/net/tipc/node.c index 3105abe97bb9..a02bcd7e07d3 100644 --- a/net/tipc/node.c +++ b/net/tipc/node.c @@ -2519,6 +2519,9 @@ int tipc_nl_node_get_link(struct sk_buff *skb, struct genl_info *info) return -EINVAL; name = nla_data(attrs[TIPC_NLA_LINK_NAME]); + if (name[strnlen(name, + nla_len(attrs[TIPC_NLA_LINK_NAME]))] != '\0') + return -EINVAL; msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL); if (!msg.skb)
Names must be null-terminated strings. If a name which is not null-terminated is passed through netlink, strstr() and similar functions can cause buffer overrun. This patch fixes this issue by returning -EINVAL if a non-null-terminated name is passed. Signed-off-by: Ma Ke <make_ruc2021@163.com> --- net/tipc/node.c | 3 +++ 1 file changed, 3 insertions(+)