From 32bf08a6257b9c7380dcd040af3c0858eee3ef05 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Mon, 20 Oct 2014 14:54:57 -0700 Subject: bpf: fix bug in eBPF verifier while comparing for verifier state equivalency the comparison was missing a check for uninitialized register. Make sure it does so and add a testcase. Fixes: f1bca824dabb ("bpf: add search pruning optimization to verifier") Cc: Hannes Frederic Sowa Signed-off-by: Alexei Starovoitov Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 801f5f3b9307..9f81818f2941 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1409,7 +1409,8 @@ static bool states_equal(struct verifier_state *old, struct verifier_state *cur) if (memcmp(&old->regs[i], &cur->regs[i], sizeof(old->regs[0])) != 0) { if (old->regs[i].type == NOT_INIT || - old->regs[i].type == UNKNOWN_VALUE) + (old->regs[i].type == UNKNOWN_VALUE && + cur->regs[i].type != NOT_INIT)) continue; return false; } -- cgit v1.2.3-59-g8ed1b From f89b7755f517cdbb755d7543eef986ee9d54e654 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Thu, 23 Oct 2014 18:41:08 -0700 Subject: bpf: split eBPF out of NET introduce two configs: - hidden CONFIG_BPF to select eBPF interpreter that classic socket filters depend on - visible CONFIG_BPF_SYSCALL (default off) that tracing and sockets can use that solves several problems: - tracing and others that wish to use eBPF don't need to depend on NET. They can use BPF_SYSCALL to allow loading from userspace or select BPF to use it directly from kernel in NET-less configs. - in 3.18 programs cannot be attached to events yet, so don't force it on - when the rest of eBPF infra is there in 3.19+, it's still useful to switch it off to minimize kernel size bloat-o-meter on x64 shows: add/remove: 0/60 grow/shrink: 0/2 up/down: 0/-15601 (-15601) tested with many different config combinations. Hopefully didn't miss anything. Signed-off-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- init/Kconfig | 14 ++++++++++++++ kernel/Makefile | 2 +- kernel/bpf/Makefile | 6 +++--- kernel/bpf/core.c | 9 +++++++++ net/Kconfig | 2 +- 5 files changed, 28 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/init/Kconfig b/init/Kconfig index 3ee28ae02cc8..2081a4d3d917 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1341,6 +1341,10 @@ config SYSCTL_ARCH_UNALIGN_ALLOW config HAVE_PCSPKR_PLATFORM bool +# interpreter that classic socket filters depend on +config BPF + bool + menuconfig EXPERT bool "Configure standard kernel features (expert users)" # Unhide debug options, to make the on-by-default options visible @@ -1521,6 +1525,16 @@ config EVENTFD If unsure, say Y. +# syscall, maps, verifier +config BPF_SYSCALL + bool "Enable bpf() system call" if EXPERT + select ANON_INODES + select BPF + default n + help + Enable the bpf() system call that allows to manipulate eBPF + programs and maps via file descriptors. + config SHMEM bool "Use full shmem filesystem" if EXPERT default y diff --git a/kernel/Makefile b/kernel/Makefile index dc5c77544fd6..17ea6d4a9a24 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -86,7 +86,7 @@ obj-$(CONFIG_RING_BUFFER) += trace/ obj-$(CONFIG_TRACEPOINTS) += trace/ obj-$(CONFIG_IRQ_WORK) += irq_work.o obj-$(CONFIG_CPU_PM) += cpu_pm.o -obj-$(CONFIG_NET) += bpf/ +obj-$(CONFIG_BPF) += bpf/ obj-$(CONFIG_PERF_EVENTS) += events/ diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index 45427239f375..0daf7f6ae7df 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -1,5 +1,5 @@ -obj-y := core.o syscall.o verifier.o - +obj-y := core.o +obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o ifdef CONFIG_TEST_BPF -obj-y += test_stub.o +obj-$(CONFIG_BPF_SYSCALL) += test_stub.o endif diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index f0c30c59b317..d6594e457a25 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -655,3 +655,12 @@ void bpf_prog_free(struct bpf_prog *fp) schedule_work(&aux->work); } EXPORT_SYMBOL_GPL(bpf_prog_free); + +/* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call + * skb_copy_bits(), so provide a weak definition of it for NET-less config. + */ +int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, + int len) +{ + return -EFAULT; +} diff --git a/net/Kconfig b/net/Kconfig index 6272420a721b..99815b5454bf 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -6,7 +6,7 @@ menuconfig NET bool "Networking support" select NLATTR select GENERIC_NET_UTILS - select ANON_INODES + select BPF ---help--- Unless you really know what you are doing, you should say Y here. The reason is that some programs need kernel networking support even -- cgit v1.2.3-59-g8ed1b