From af91acbc62999d62e2ca1e80f660d20561ca55d3 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Wed, 30 Oct 2019 16:30:19 -0700 Subject: bpf: Fix bpf jit kallsym access Jiri reported crash when JIT is on, but net.core.bpf_jit_kallsyms is off. bpf_prog_kallsyms_find() was skipping addr->bpf_prog resolution logic in oops and stack traces. That's incorrect. It should only skip addr->name resolution for 'cat /proc/kallsyms'. That's what bpf_jit_kallsyms and bpf_jit_harden protect. Fixes: 3dec541b2e63 ("bpf: Add support for BTF pointers to x86 JIT") Reported-by: Jiri Olsa Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20191030233019.1187404-1-ast@kernel.org --- kernel/bpf/core.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'kernel/bpf/core.c') diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 673f5d40a93e..8d3fbc86ca5e 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -668,9 +668,6 @@ static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr) { struct latch_tree_node *n; - if (!bpf_jit_kallsyms_enabled()) - return NULL; - n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); return n ? container_of(n, struct bpf_prog_aux, ksym_tnode)->prog : -- cgit v1.2.3-59-g8ed1b From 6e07a6341277a1dbdf5ed0c41921033c234c1635 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Sat, 2 Nov 2019 00:18:00 +0100 Subject: bpf: Switch BPF probe insns to bpf_probe_read_kernel Commit 2a02759ef5f8 ("bpf: Add support for BTF pointers to interpreter") explicitly states that the pointer to BTF object is a pointer to a kernel object or NULL. Therefore we should also switch to using the strict kernel probe helper which is restricted to kernel addresses only when architectures have non-overlapping address spaces. Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/d2b90827837685424a4b8008dfe0460558abfada.1572649915.git.daniel@iogearbox.net --- kernel/bpf/core.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'kernel/bpf/core.c') diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 8d3fbc86ca5e..df82d5a42b23 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1306,11 +1306,12 @@ 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) +u64 __weak bpf_probe_read_kernel(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 @@ -1566,9 +1567,9 @@ 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); \ +#define LDX_PROBE(SIZEOP, SIZE) \ + LDX_PROBE_MEM_##SIZEOP: \ + bpf_probe_read_kernel(&DST, SIZE, (const void *)(long) SRC); \ CONT; LDX_PROBE(B, 1) LDX_PROBE(H, 2) -- cgit v1.2.3-59-g8ed1b