On 10/05/2017 11:26 PM, Jakub Kicinski wrote:
On Thu, 05 Oct 2017 23:10:03 +0200, Daniel Borkmann wrote:
include/linux/bpf_verifier.h | 7 +++--
kernel/bpf/verifier.c | 64
+++++++++++++++++++++++++++++++-------------
2 files changed, 50 insertions(+), 21 deletions(-)
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 598802dd1897..c0f0e210c3f8 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -140,10 +140,13 @@ struct bpf_verifier_env {
bool seen_direct_write;
struct bpf_insn_aux_data *insn_aux_data; /* array of per-insn state */
- u32 log_level;
+ char __user *log_ubuf;
+ u32 log_usize;
+ u32 log_ulen;
+ char *log_buf;
u32 log_size;
u32 log_len;
- char *log_buf;
+ u32 log_level;
Small request: given we'd now have log_{level,ubuf,usize,ulen,buf,size,len}
in struct bpf_verifier_env, could we abstract that a bit e.g. into something
like struct bpf_verifier_log, which has level and kbuf and ubuf as members
of which {k,u}buf would be something like struct bpf_verifier_buf with three
members (mem or buf, len_total, len_used) or such. I think most of patch 1
is on passing env into verbose, so likely wouldn't be too much change required
for this, but would be nice to make that a bit more structured if we need to
touch it anyway.
I thought about it but got put off by the fact that on of the bufs has
a special __user marking.. So I don't think we can really have a common
struct bpf_verifier_buf for the two :S Any suggestions on how to work
around that?
Little bit annoying, I know. We have same 'issue' with struct sock_fprog_kern
and struct sock_fprog, probably something similar would be needed here for
the bpf_verifier_buf thing as well to make it two structs.
ret = -ENOMEM;
- env->log_buf = vmalloc(env->log_size);
+ env->log_buf = page_address(alloc_page(GFP_USER));
alloc_page() can return NULL, if I spot this correctly, then page_address()
cannot handle NULL and would try to deref it, no? Am I missing something?
Oh, I need to fix the nfp driver too, then!
