Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2019-10-27

The following pull-request contains BPF updates for your *net-next* tree.

We've added 52 non-merge commits during the last 11 day(s) which contain
a total of 65 files changed, 2604 insertions(+), 1100 deletions(-).

The main changes are:

 1) Revolutionize BPF tracing by using in-kernel BTF to type check BPF
    assembly code. The work here teaches BPF verifier to recognize
    kfree_skb()'s first argument as 'struct sk_buff *' in tracepoints
    such that verifier allows direct use of bpf_skb_event_output() helper
    used in tc BPF et al (w/o probing memory access) that dumps skb data
    into perf ring buffer. Also add direct loads to probe memory in order
    to speed up/replace bpf_probe_read() calls, from Alexei Starovoitov.

 2) Big batch of changes to improve libbpf and BPF kselftests. Besides
    others: generalization of libbpf's CO-RE relocation support to now
    also include field existence relocations, revamp the BPF kselftest
    Makefile to add test runner concept allowing to exercise various
    ways to build BPF programs, and teach bpf_object__open() and friends
    to automatically derive BPF program type/expected attach type from
    section names to ease their use, from Andrii Nakryiko.

 3) Fix deadlock in stackmap's build-id lookup on rq_lock(), from Song Liu.

 4) Allow to read BTF as raw data from bpftool. Most notable use case
    is to dump /sys/kernel/btf/vmlinux through this, from Jiri Olsa.

 5) Use bpf_redirect_map() helper in libbpf's AF_XDP helper prog which
    manages to improve "rx_drop" performance by ~4%., from Björn Töpel.

 6) Fix to restore the flow dissector after reattach BPF test and also
    fix error handling in bpf_helper_defs.h generation, from Jakub Sitnicki.

 7) Improve verifier's BTF ctx access for use outside of raw_tp, from
    Martin KaFai Lau.

 8) Improve documentation for AF_XDP with new sections and to reflect
    latest features, from Magnus Karlsson.

 9) Add back 'version' section parsing to libbpf for old kernels, from
    John Fastabend.

10) Fix strncat bounds error in libbpf's libbpf_prog_type_by_name(),
    from KP Singh.

11) Turn on -mattr=+alu32 in LLVM by default for BPF kselftests in order
    to improve insn coverage for built BPF progs, from Yonghong Song.

12) Misc minor cleanups and fixes, from various others.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 38 insertions, 1 deletions

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 66088a9e9b9e..673f5d40a93e 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -30,7 +30,7 @@
 #include <linux/kallsyms.h>
 #include <linux/rcupdate.h>
 #include <linux/perf_event.h>
-
+#include <linux/extable.h>
 #include <asm/unaligned.h>
 
 /* Registers */
@@ -712,6 +712,24 @@ bool is_bpf_text_address(unsigned long addr)
 	return ret;
 }
 
+const struct exception_table_entry *search_bpf_extables(unsigned long addr)
+{
+	const struct exception_table_entry *e = NULL;
+	struct bpf_prog *prog;
+
+	rcu_read_lock();
+	prog = bpf_prog_kallsyms_find(addr);
+	if (!prog)
+		goto out;
+	if (!prog->aux->num_exentries)
+		goto out;
+
+	e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr);
+out:
+	rcu_read_unlock();
+	return e;
+}
+
 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 		    char *sym)
 {
@@ -1291,6 +1309,11 @@ bool bpf_opcode_in_insntable(u8 code)
 }
 
 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
+u64 __weak bpf_probe_read(void * dst, u32 size, const void * unsafe_ptr)
+{
+	memset(dst, 0, size);
+	return -EFAULT;
+}
 /**
  *	__bpf_prog_run - run eBPF program on a given context
  *	@regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers
@@ -1310,6 +1333,10 @@ static u64 __no_fgcse ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u6
 		/* Non-UAPI available opcodes. */
 		[BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS,
 		[BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
+		[BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B,
+		[BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H,
+		[BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W,
+		[BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW,
 	};
 #undef BPF_INSN_3_LBL
 #undef BPF_INSN_2_LBL
@@ -1542,6 +1569,16 @@ out:
 	LDST(W,  u32)
 	LDST(DW, u64)
 #undef LDST
+#define LDX_PROBE(SIZEOP, SIZE)						\
+	LDX_PROBE_MEM_##SIZEOP:						\
+		bpf_probe_read(&DST, SIZE, (const void *)(long) SRC);	\
+		CONT;
+	LDX_PROBE(B,  1)
+	LDX_PROBE(H,  2)
+	LDX_PROBE(W,  4)
+	LDX_PROBE(DW, 8)
+#undef LDX_PROBE
+
 	STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
 		atomic_add((u32) SRC, (atomic_t *)(unsigned long)
 			   (DST + insn->off));