From 6890896bd765b0504761c61901c9804fca23bfb2 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Fri, 24 Apr 2020 16:59:41 -0700 Subject: bpf: Fix missing bpf_base_func_proto in cgroup_base_func_proto for CGROUP_NET=n linux-next build bot reported compile issue [1] with one of its configs. It looks like when we have CONFIG_NET=n and CONFIG_BPF{,_SYSCALL}=y, we are missing the bpf_base_func_proto definition (from net/core/filter.c) in cgroup_base_func_proto. I'm reshuffling the code a bit to make it work. The common helpers are moved into kernel/bpf/helpers.c and the bpf_base_func_proto is exported from there. Also, bpf_get_raw_cpu_id goes into kernel/bpf/core.c akin to existing bpf_user_rnd_u32. [1] https://lore.kernel.org/linux-next/CAKH8qBsBvKHswiX1nx40LgO+BGeTmb1NX8tiTttt_0uu6T3dCA@mail.gmail.com/T/#mff8b0c083314c68c2e2ef0211cb11bc20dc13c72 Fixes: 0456ea170cd6 ("bpf: Enable more helpers for BPF_PROG_TYPE_CGROUP_{DEVICE,SYSCTL,SOCKOPT}") Signed-off-by: Stanislav Fomichev Signed-off-by: Alexei Starovoitov Cc: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200424235941.58382-1-sdf@google.com --- include/linux/filter.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/linux/filter.h') diff --git a/include/linux/filter.h b/include/linux/filter.h index 9b5aa5c483cc..af37318bb1c5 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -863,8 +863,6 @@ int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog); int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog, bpf_aux_classic_check_t trans, bool save_orig); void bpf_prog_destroy(struct bpf_prog *fp); -const struct bpf_func_proto * -bpf_base_func_proto(enum bpf_func_id func_id); int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk); int sk_attach_bpf(u32 ufd, struct sock *sk); -- cgit v1.2.3-71-gd317 From d26c0cc53950464a24adfa76867f1d71f0cbbea6 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 30 Apr 2020 23:30:47 +0200 Subject: bpf: Avoid gcc-10 stringop-overflow warning in struct bpf_prog gcc-10 warns about accesses to zero-length arrays: kernel/bpf/core.c: In function 'bpf_patch_insn_single': cc1: warning: writing 8 bytes into a region of size 0 [-Wstringop-overflow=] In file included from kernel/bpf/core.c:21: include/linux/filter.h:550:20: note: at offset 0 to object 'insnsi' with size 0 declared here 550 | struct bpf_insn insnsi[0]; | ^~~~~~ In this case, we really want to have two flexible-array members, but that is not possible. Removing the union to make insnsi a flexible-array member while leaving insns as a zero-length array fixes the warning, as nothing writes to the other one in that way. This trick only works on linux-3.18 or higher, as older versions had additional members in the union. Fixes: 60a3b2253c41 ("net: bpf: make eBPF interpreter images read-only") Signed-off-by: Arnd Bergmann Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200430213101.135134-6-arnd@arndb.de --- include/linux/filter.h | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'include/linux/filter.h') diff --git a/include/linux/filter.h b/include/linux/filter.h index af37318bb1c5..73d06a39e2d6 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -545,10 +545,8 @@ struct bpf_prog { unsigned int (*bpf_func)(const void *ctx, const struct bpf_insn *insn); /* Instructions for interpreter */ - union { - struct sock_filter insns[0]; - struct bpf_insn insnsi[0]; - }; + struct sock_filter insns[0]; + struct bpf_insn insnsi[]; }; struct sk_filter { -- cgit v1.2.3-71-gd317