diff options
author | Martin KaFai Lau <kafai@fb.com> | 2022-08-17 09:17:17 +0300 |
---|---|---|
committer | Alexei Starovoitov <ast@kernel.org> | 2022-08-19 03:06:12 +0300 |
commit | 24426654ed3ae83d1127511891fb782c54f49203 (patch) | |
tree | 7145914d9472d48429f375131656cb1080afd489 /include | |
parent | 4d748f9916076399f01c259d30fe1b88abe8f622 (diff) | |
download | linux-24426654ed3ae83d1127511891fb782c54f49203.tar.xz |
bpf: net: Avoid sk_setsockopt() taking sk lock when called from bpf
Most of the code in bpf_setsockopt(SOL_SOCKET) are duplicated from
the sk_setsockopt(). The number of supported optnames are
increasing ever and so as the duplicated code.
One issue in reusing sk_setsockopt() is that the bpf prog
has already acquired the sk lock. This patch adds a
has_current_bpf_ctx() to tell if the sk_setsockopt() is called from
a bpf prog. The bpf prog calling bpf_setsockopt() is either running
in_task() or in_serving_softirq(). Both cases have the current->bpf_ctx
initialized. Thus, the has_current_bpf_ctx() only needs to
test !!current->bpf_ctx.
This patch also adds sockopt_{lock,release}_sock() helpers
for sk_setsockopt() to use. These helpers will test
has_current_bpf_ctx() before acquiring/releasing the lock. They are
in EXPORT_SYMBOL for the ipv6 module to use in a latter patch.
Note on the change in sock_setbindtodevice(). sockopt_lock_sock()
is done in sock_setbindtodevice() instead of doing the lock_sock
in sock_bindtoindex(..., lock_sk = true).
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220817061717.4175589-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/bpf.h | 13 | ||||
-rw-r--r-- | include/net/sock.h | 3 |
2 files changed, 16 insertions, 0 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index a627a02cf8ab..39bd36359c1e 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1966,6 +1966,15 @@ static inline bool unprivileged_ebpf_enabled(void) return !sysctl_unprivileged_bpf_disabled; } +/* Not all bpf prog type has the bpf_ctx. + * For the bpf prog type that has initialized the bpf_ctx, + * this function can be used to decide if a kernel function + * is called by a bpf program. + */ +static inline bool has_current_bpf_ctx(void) +{ + return !!current->bpf_ctx; +} #else /* !CONFIG_BPF_SYSCALL */ static inline struct bpf_prog *bpf_prog_get(u32 ufd) { @@ -2175,6 +2184,10 @@ static inline bool unprivileged_ebpf_enabled(void) return false; } +static inline bool has_current_bpf_ctx(void) +{ + return false; +} #endif /* CONFIG_BPF_SYSCALL */ void __bpf_free_used_btfs(struct bpf_prog_aux *aux, diff --git a/include/net/sock.h b/include/net/sock.h index 05a1bbdf5805..352b9458fdc6 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1749,6 +1749,9 @@ static inline void unlock_sock_fast(struct sock *sk, bool slow) } } +void sockopt_lock_sock(struct sock *sk); +void sockopt_release_sock(struct sock *sk); + /* Used by processes to "lock" a socket state, so that * interrupts and bottom half handlers won't change it * from under us. It essentially blocks any incoming |