From 4b1c5d917d34f705096bb7dd8a2bd19b0881970e Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 12 Sep 2018 10:29:11 -0700 Subject: bpf: btf: Fix end boundary calculation for type section The end boundary math for type section is incorrect in btf_check_all_metas(). It just happens that hdr->type_off is always 0 for now because there are only two sections (type and string) and string section must be at the end (ensured in btf_parse_str_sec). However, type_off may not be 0 if a new section would be added later. This patch fixes it. Fixes: f80442a4cd18 ("bpf: btf: Change how section is supported in btf_header") Reported-by: Dmitry Vyukov Signed-off-by: Martin KaFai Lau Acked-by: Yonghong Song Signed-off-by: Daniel Borkmann --- kernel/bpf/btf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 2590700237c1..138f0302692e 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -1844,7 +1844,7 @@ static int btf_check_all_metas(struct btf_verifier_env *env) hdr = &btf->hdr; cur = btf->nohdr_data + hdr->type_off; - end = btf->nohdr_data + hdr->type_len; + end = cur + hdr->type_len; env->log_type_id = 1; while (cur < end) { -- cgit v1.2.3 From dd066823db2ac4e22f721ec85190817b58059a54 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Wed, 12 Sep 2018 14:06:10 -0700 Subject: bpf/verifier: disallow pointer subtraction Subtraction of pointers was accidentally allowed for unpriv programs by commit 82abbf8d2fc4. Revert that part of commit. Fixes: 82abbf8d2fc4 ("bpf: do not allow root to mangle valid pointers") Reported-by: Jann Horn Acked-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann --- kernel/bpf/verifier.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 92246117d2b0..bb07e74b34a2 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -3163,7 +3163,7 @@ static int adjust_reg_min_max_vals(struct bpf_verifier_env *env, * an arbitrary scalar. Disallow all math except * pointer subtraction */ - if (opcode == BPF_SUB){ + if (opcode == BPF_SUB && env->allow_ptr_leaks) { mark_reg_unknown(env, regs, insn->dst_reg); return 0; } -- cgit v1.2.3 From 4c3d795cb012a378855543a775408fba1ccff6f2 Mon Sep 17 00:00:00 2001 From: Tushar Dave Date: Wed, 12 Sep 2018 22:15:29 +0200 Subject: bpf: use __GFP_COMP while allocating page Helper bpg_msg_pull_data() can allocate multiple pages while linearizing multiple scatterlist elements into one shared page. However, if the shared page has size > PAGE_SIZE, using copy_page_to_iter() causes below warning. e.g. [ 6367.019832] WARNING: CPU: 2 PID: 7410 at lib/iov_iter.c:825 page_copy_sane.part.8+0x0/0x8 To avoid above warning, use __GFP_COMP while allocating multiple contiguous pages. Fixes: 015632bb30da ("bpf: sk_msg program helper bpf_sk_msg_pull_data") Signed-off-by: Tushar Dave Signed-off-by: Daniel Borkmann --- net/core/filter.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/core/filter.c b/net/core/filter.c index aecdeba052d3..5e00f2b85a56 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2344,7 +2344,8 @@ BPF_CALL_4(bpf_msg_pull_data, if (unlikely(bytes_sg_total > copy)) return -EINVAL; - page = alloc_pages(__GFP_NOWARN | GFP_ATOMIC, get_order(copy)); + page = alloc_pages(__GFP_NOWARN | GFP_ATOMIC | __GFP_COMP, + get_order(copy)); if (unlikely(!page)) return -ENOMEM; p = page_address(page); -- cgit v1.2.3