Re: [PATCH bpf-next v2 2/2] bpf: use kvmalloc for map keys in syscalls

On 08/19, Daniel Borkmann wrote:

On 8/17/21 5:45 PM, Stanislav Fomichev wrote:

quoted

Same as previous patch but for the keys. memdup_bpfptr is renamed
to vmemdup_bpfptr (and converted to kvmalloc).

Signed-off-by: Stanislav Fomichev <redacted>
---
  include/linux/bpfptr.h | 12 ++++++++++--
  kernel/bpf/syscall.c   | 34 +++++++++++++++++-----------------
  2 files changed, 27 insertions(+), 19 deletions(-)

diff --git a/include/linux/bpfptr.h b/include/linux/bpfptr.h
index 5cdeab497cb3..84eeffb4316a 100644
--- a/include/linux/bpfptr.h
+++ b/include/linux/bpfptr.h

@@ -62,9 +62,17 @@ static inline int copy_to_bpfptr_offset(bpfptr_t  

dst, size_t offset,

quoted

  	return copy_to_sockptr_offset((sockptr_t) dst, offset, src, size);
  }
-static inline void *memdup_bpfptr(bpfptr_t src, size_t len)
+static inline void *vmemdup_bpfptr(bpfptr_t src, size_t len)

nit: should we just name it kvmemdup_bpfptr() in that case?

Sounds good!

quoted

  {
-	return memdup_sockptr((sockptr_t) src, len);
+	void *p = kvmalloc(len, GFP_USER | __GFP_NOWARN);
+
+	if (!p)
+		return ERR_PTR(-ENOMEM);
+	if (copy_from_sockptr(p, (sockptr_t) src, len)) {

Also, I think this one should rather use copy_from_bpfptr() here.

Ah, missed that one, thanks!

quoted

+		kvfree(p);
+		return ERR_PTR(-EFAULT);
+	}
+	return p;
  }

Rest lgtm, thanks!