linux-crypto.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Andy Lutomirski <luto@kernel.org>
To: Daniel Borkmann <daniel@iogearbox.net>,
	Netdev <netdev@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux Crypto Mailing List <linux-crypto@vger.kernel.org>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>,
	Hannes Frederic Sowa <hannes@stressinduktion.org>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Eric Dumazet <edumazet@google.com>,
	Eric Biggers <ebiggers3@gmail.com>,
	Tom Herbert <tom@herbertland.com>,
	"David S. Miller" <davem@davemloft.net>,
	Andy Lutomirski <luto@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>
Subject: [PATCH v2 5/8] bpf: Avoid copying the entire BPF program when hashing it
Date: Tue, 10 Jan 2017 15:24:43 -0800	[thread overview]
Message-ID: <7d95d2483eb648960a9f33e38a01fcc678da545e.1484090585.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1484090585.git.luto@kernel.org>
In-Reply-To: <cover.1484090585.git.luto@kernel.org>

The sha256 helpers can consume a message incrementally, so there's no need
to allocate a buffer to store the whole blob to be hashed.

This may be a slight slowdown for very long messages because gcc can't
inline the sha256_update() calls.  For reasonably-sized programs,
however, this should be a considerable speedup as vmalloc() is quite
slow.

Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
 kernel/bpf/core.c | 33 +++++++++++++--------------------
 1 file changed, 13 insertions(+), 20 deletions(-)

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 668b92f6ab58..106162a1bc54 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -149,44 +149,37 @@ void __bpf_prog_free(struct bpf_prog *fp)
 int bpf_prog_calc_digest(struct bpf_prog *fp)
 {
 	struct sha256_state sha;
-	u32 i, psize;
-	struct bpf_insn *dst;
+	u32 i;
 	bool was_ld_map;
-	u8 *raw;
-
-	psize = bpf_prog_insn_size(fp);
-	raw = vmalloc(psize);
-	if (!raw)
-		return -ENOMEM;
 
 	sha256_init_direct(&sha);
 
 	/* We need to take out the map fd for the digest calculation
 	 * since they are unstable from user space side.
 	 */
-	dst = (void *)raw;
 	for (i = 0, was_ld_map = false; i < fp->len; i++) {
-		dst[i] = fp->insnsi[i];
+		struct bpf_insn insn = fp->insnsi[i];
+
 		if (!was_ld_map &&
-		    dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
-		    dst[i].src_reg == BPF_PSEUDO_MAP_FD) {
+		    insn.code == (BPF_LD | BPF_IMM | BPF_DW) &&
+		    insn.src_reg == BPF_PSEUDO_MAP_FD) {
 			was_ld_map = true;
-			dst[i].imm = 0;
+			insn.imm = 0;
 		} else if (was_ld_map &&
-			   dst[i].code == 0 &&
-			   dst[i].dst_reg == 0 &&
-			   dst[i].src_reg == 0 &&
-			   dst[i].off == 0) {
+			   insn.code == 0 &&
+			   insn.dst_reg == 0 &&
+			   insn.src_reg == 0 &&
+			   insn.off == 0) {
 			was_ld_map = false;
-			dst[i].imm = 0;
+			insn.imm = 0;
 		} else {
 			was_ld_map = false;
 		}
+
+		sha256_update_direct(&sha, (const u8 *)&insn, sizeof(insn));
 	}
 
-	sha256_update_direct(&sha, raw, psize);
 	sha256_final_direct(&sha, fp->digest);
-	vfree(raw);
 	return 0;
 }
 
-- 
2.9.3

  parent reply	other threads:[~2017-01-10 23:24 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-10 23:24 [PATCH v2 0/8] Switch BPF's digest to SHA256 Andy Lutomirski
2017-01-10 23:24 ` [PATCH v2 1/8] crypto/sha256: Factor out the parts of base API that don't use shash_desc Andy Lutomirski
2017-01-10 23:24 ` [PATCH v2 2/8] crypto/sha256: Export a sha256_{init,update,final}_direct() API Andy Lutomirski
2017-01-10 23:24 ` [PATCH v2 3/8] crypto/sha256: Build the SHA256 core separately from the crypto module Andy Lutomirski
2017-01-10 23:24 ` [PATCH v2 4/8] bpf: Use SHA256 instead of SHA1 for bpf digests Andy Lutomirski
2017-01-10 23:24 ` Andy Lutomirski [this message]
2017-01-10 23:24 ` [PATCH v2 6/8] bpf: Rename fdinfo's prog_digest to prog_sha256 Andy Lutomirski
2017-01-10 23:24 ` [PATCH v2 7/8] net: Rename TCA*BPF_DIGEST to ..._SHA256 Andy Lutomirski
2017-01-11  0:50   ` Daniel Borkmann
2017-01-11  3:11     ` Andy Lutomirski
2017-01-11  9:09       ` Daniel Borkmann
2017-01-11 18:19         ` Andy Lutomirski
2017-01-13 23:08           ` Daniel Borkmann
2017-01-10 23:24 ` [PATCH v2 8/8] crypto/testmgr: Allocate only the required output size for hash tests Andy Lutomirski
2017-01-11 15:13   ` David Laight
2017-01-11 18:10     ` Andy Lutomirski
2017-01-12  7:47   ` Herbert Xu
2017-01-12  7:52     ` Andy Lutomirski
2017-01-12 16:44   ` Herbert Xu
2017-01-11  1:09 ` [PATCH v2 0/8] Switch BPF's digest to SHA256 Alexei Starovoitov

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=7d95d2483eb648960a9f33e38a01fcc678da545e.1484090585.git.luto@kernel.org \
    --to=luto@kernel.org \
    --cc=Jason@zx2c4.com \
    --cc=alexei.starovoitov@gmail.com \
    --cc=ast@kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=davem@davemloft.net \
    --cc=ebiggers3@gmail.com \
    --cc=edumazet@google.com \
    --cc=hannes@stressinduktion.org \
    --cc=linux-crypto@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=tom@herbertland.com \
    --subject='Re: [PATCH v2 5/8] bpf: Avoid copying the entire BPF program when hashing it' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).