| Message ID | 20231011170321.73950-4-daan.j.demeyer@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | Add cgroup sockaddr hooks for unix sockets | expand |
From: Daan De Meyer <daan.j.demeyer@gmail.com> Date: Wed, 11 Oct 2023 19:03:12 +0200 > As prep for adding unix socket support to the cgroup sockaddr hooks, > let's add a kfunc bpf_sock_addr_set_sun_path() that allows modifying a unix > sockaddr from bpf. While this is already possible for AF_INET and AF_INET6, > we'll need this kfunc when we add unix socket support since modifying the > address for those requires modifying both the address and the sockaddr > length. > > Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com> > --- > kernel/bpf/btf.c | 1 + > net/core/filter.c | 40 +++++++++++++++++++++++++++++++++++++++- > 2 files changed, 40 insertions(+), 1 deletion(-) > > diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c > index 69101200c124..15d71d2986d3 100644 > --- a/kernel/bpf/btf.c > +++ b/kernel/bpf/btf.c > @@ -7850,6 +7850,7 @@ static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type) > case BPF_PROG_TYPE_SYSCALL: > return BTF_KFUNC_HOOK_SYSCALL; > case BPF_PROG_TYPE_CGROUP_SKB: > + case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: > return BTF_KFUNC_HOOK_CGROUP_SKB; > case BPF_PROG_TYPE_SCHED_ACT: > return BTF_KFUNC_HOOK_SCHED_ACT; > diff --git a/net/core/filter.c b/net/core/filter.c > index a094694899c9..12fbd8a560c8 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c > @@ -81,6 +81,7 @@ > #include <net/xdp.h> > #include <net/mptcp.h> > #include <net/netfilter/nf_conntrack_bpf.h> > +#include <linux/un.h> > > static const struct bpf_func_proto * > bpf_sk_base_func_proto(enum bpf_func_id func_id); > @@ -11752,6 +11753,32 @@ __bpf_kfunc int bpf_dynptr_from_xdp(struct xdp_buff *xdp, u64 flags, > > return 0; > } > + > +__bpf_kfunc int bpf_sock_addr_set_sun_path(struct bpf_sock_addr_kern *sa_kern, > + const u8 *sun_path, u32 sun_path__sz) > +{ > + struct sockaddr *sa = sa_kern->uaddr; > + struct sockaddr_un *un; > + > + if (sa_kern->sk->sk_family != AF_UNIX) > + return -EINVAL; > + > + /* We do not allow changing the address of unnamed unix sockets. */ > + if (sa_kern->uaddrlen == 0) > + return -EINVAL; Instead of adding this check, you can call the hooks after unix_validate_addr() in connect() and sendmsg(). In unix_getname(), you can move up the bpf hooks into the else branch below. if (!addr) { ... } else { ... <-- here } > + > + /* We do not allow changing the address to unnamed or larger than the > + * maximum allowed address size for a unix sockaddr. > + */ > + if (sun_path__sz == 0 || sun_path__sz > UNIX_PATH_MAX) > + return -EINVAL; > + > + un = (struct sockaddr_un *)sa; > + memcpy(un->sun_path, sun_path, sun_path__sz); > + sa_kern->uaddrlen = offsetof(struct sockaddr_un, sun_path) + sun_path__sz; > + > + return 0; > +} > __diag_pop(); > > int bpf_dynptr_from_skb_rdonly(struct sk_buff *skb, u64 flags, > @@ -11776,6 +11803,10 @@ BTF_SET8_START(bpf_kfunc_check_set_xdp) > BTF_ID_FLAGS(func, bpf_dynptr_from_xdp) > BTF_SET8_END(bpf_kfunc_check_set_xdp) > > +BTF_SET8_START(bpf_kfunc_check_set_sock_addr) > +BTF_ID_FLAGS(func, bpf_sock_addr_set_sun_path) > +BTF_SET8_END(bpf_kfunc_check_set_sock_addr) > + > static const struct btf_kfunc_id_set bpf_kfunc_set_skb = { > .owner = THIS_MODULE, > .set = &bpf_kfunc_check_set_skb, > @@ -11786,6 +11817,11 @@ static const struct btf_kfunc_id_set bpf_kfunc_set_xdp = { > .set = &bpf_kfunc_check_set_xdp, > }; > > +static const struct btf_kfunc_id_set bpf_kfunc_set_sock_addr = { > + .owner = THIS_MODULE, > + .set = &bpf_kfunc_check_set_sock_addr, > +}; > + > static int __init bpf_kfunc_init(void) > { > int ret; > @@ -11800,7 +11836,9 @@ static int __init bpf_kfunc_init(void) > ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_XMIT, &bpf_kfunc_set_skb); > ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_SEG6LOCAL, &bpf_kfunc_set_skb); > ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_NETFILTER, &bpf_kfunc_set_skb); > - return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &bpf_kfunc_set_xdp); > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &bpf_kfunc_set_xdp); > + return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SOCK_ADDR, > + &bpf_kfunc_set_sock_addr); > } > late_initcall(bpf_kfunc_init); > > -- > 2.41.0
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 69101200c124..15d71d2986d3 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -7850,6 +7850,7 @@ static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type) case BPF_PROG_TYPE_SYSCALL: return BTF_KFUNC_HOOK_SYSCALL; case BPF_PROG_TYPE_CGROUP_SKB: + case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: return BTF_KFUNC_HOOK_CGROUP_SKB; case BPF_PROG_TYPE_SCHED_ACT: return BTF_KFUNC_HOOK_SCHED_ACT; diff --git a/net/core/filter.c b/net/core/filter.c index a094694899c9..12fbd8a560c8 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -81,6 +81,7 @@ #include <net/xdp.h> #include <net/mptcp.h> #include <net/netfilter/nf_conntrack_bpf.h> +#include <linux/un.h> static const struct bpf_func_proto * bpf_sk_base_func_proto(enum bpf_func_id func_id); @@ -11752,6 +11753,32 @@ __bpf_kfunc int bpf_dynptr_from_xdp(struct xdp_buff *xdp, u64 flags, return 0; } + +__bpf_kfunc int bpf_sock_addr_set_sun_path(struct bpf_sock_addr_kern *sa_kern, + const u8 *sun_path, u32 sun_path__sz) +{ + struct sockaddr *sa = sa_kern->uaddr; + struct sockaddr_un *un; + + if (sa_kern->sk->sk_family != AF_UNIX) + return -EINVAL; + + /* We do not allow changing the address of unnamed unix sockets. */ + if (sa_kern->uaddrlen == 0) + return -EINVAL; + + /* We do not allow changing the address to unnamed or larger than the + * maximum allowed address size for a unix sockaddr. + */ + if (sun_path__sz == 0 || sun_path__sz > UNIX_PATH_MAX) + return -EINVAL; + + un = (struct sockaddr_un *)sa; + memcpy(un->sun_path, sun_path, sun_path__sz); + sa_kern->uaddrlen = offsetof(struct sockaddr_un, sun_path) + sun_path__sz; + + return 0; +} __diag_pop(); int bpf_dynptr_from_skb_rdonly(struct sk_buff *skb, u64 flags, @@ -11776,6 +11803,10 @@ BTF_SET8_START(bpf_kfunc_check_set_xdp) BTF_ID_FLAGS(func, bpf_dynptr_from_xdp) BTF_SET8_END(bpf_kfunc_check_set_xdp) +BTF_SET8_START(bpf_kfunc_check_set_sock_addr) +BTF_ID_FLAGS(func, bpf_sock_addr_set_sun_path) +BTF_SET8_END(bpf_kfunc_check_set_sock_addr) + static const struct btf_kfunc_id_set bpf_kfunc_set_skb = { .owner = THIS_MODULE, .set = &bpf_kfunc_check_set_skb, @@ -11786,6 +11817,11 @@ static const struct btf_kfunc_id_set bpf_kfunc_set_xdp = { .set = &bpf_kfunc_check_set_xdp, }; +static const struct btf_kfunc_id_set bpf_kfunc_set_sock_addr = { + .owner = THIS_MODULE, + .set = &bpf_kfunc_check_set_sock_addr, +}; + static int __init bpf_kfunc_init(void) { int ret; @@ -11800,7 +11836,9 @@ static int __init bpf_kfunc_init(void) ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_XMIT, &bpf_kfunc_set_skb); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_LWT_SEG6LOCAL, &bpf_kfunc_set_skb); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_NETFILTER, &bpf_kfunc_set_skb); - return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &bpf_kfunc_set_xdp); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &bpf_kfunc_set_xdp); + return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SOCK_ADDR, + &bpf_kfunc_set_sock_addr); } late_initcall(bpf_kfunc_init);
As prep for adding unix socket support to the cgroup sockaddr hooks, let's add a kfunc bpf_sock_addr_set_sun_path() that allows modifying a unix sockaddr from bpf. While this is already possible for AF_INET and AF_INET6, we'll need this kfunc when we add unix socket support since modifying the address for those requires modifying both the address and the sockaddr length. Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com> --- kernel/bpf/btf.c | 1 + net/core/filter.c | 40 +++++++++++++++++++++++++++++++++++++++- 2 files changed, 40 insertions(+), 1 deletion(-)