Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2023-12-18

This PR is larger than usual and contains changes in various parts
of the kernel.

The main changes are:

1) Fix kCFI bugs in BPF, from Peter Zijlstra.

End result: all forms of indirect calls from BPF into kernel
and from kernel into BPF work with CFI enabled. This allows BPF
to work with CONFIG_FINEIBT=y.

2) Introduce BPF token object, from Andrii Nakryiko.

It adds an ability to delegate a subset of BPF features from privileged
daemon (e.g., systemd) through special mount options for userns-bound
BPF FS to a trusted unprivileged application. The design accommodates
suggestions from Christian Brauner and Paul Moore.

Example:
$ sudo mkdir -p /sys/fs/bpf/token
$ sudo mount -t bpf bpffs /sys/fs/bpf/token \
             -o delegate_cmds=prog_load:MAP_CREATE \
             -o delegate_progs=kprobe \
             -o delegate_attachs=xdp

3) Various verifier improvements and fixes, from Andrii Nakryiko, Andrei Matei.

 - Complete precision tracking support for register spills
 - Fix verification of possibly-zero-sized stack accesses
 - Fix access to uninit stack slots
 - Track aligned STACK_ZERO cases as imprecise spilled registers.
   It improves the verifier "instructions processed" metric from single
   digit to 50-60% for some programs.
 - Fix verifier retval logic

4) Support for VLAN tag in XDP hints, from Larysa Zaremba.

5) Allocate BPF trampoline via bpf_prog_pack mechanism, from Song Liu.

End result: better memory utilization and lower I$ miss for calls to BPF
via BPF trampoline.

6) Fix race between BPF prog accessing inner map and parallel delete,
from Hou Tao.

7) Add bpf_xdp_get_xfrm_state() kfunc, from Daniel Xu.

It allows BPF interact with IPSEC infra. The intent is to support
software RSS (via XDP) for the upcoming ipsec pcpu work.
Experiments on AWS demonstrate single tunnel pcpu ipsec reaching
line rate on 100G ENA nics.

8) Expand bpf_cgrp_storage to support cgroup1 non-attach, from Yafang Shao.

9) BPF file verification via fsverity, from Song Liu.

It allows BPF progs get fsverity digest.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (164 commits)
  bpf: Ensure precise is reset to false in __mark_reg_const_zero()
  selftests/bpf: Add more uprobe multi fail tests
  bpf: Fail uprobe multi link with negative offset
  selftests/bpf: Test the release of map btf
  s390/bpf: Fix indirect trampoline generation
  selftests/bpf: Temporarily disable dummy_struct_ops test on s390
  x86/cfi,bpf: Fix bpf_exception_cb() signature
  bpf: Fix dtor CFI
  cfi: Add CFI_NOSEAL()
  x86/cfi,bpf: Fix bpf_struct_ops CFI
  x86/cfi,bpf: Fix bpf_callback_t CFI
  x86/cfi,bpf: Fix BPF JIT call
  cfi: Flip headers
  selftests/bpf: Add test for abnormal cnt during multi-kprobe attachment
  selftests/bpf: Don't use libbpf_get_error() in kprobe_multi_test
  selftests/bpf: Add test for abnormal cnt during multi-uprobe attachment
  bpf: Limit the number of kprobes when attaching program to multiple kprobes
  bpf: Limit the number of uprobes when attaching program to multiple uprobes
  bpf: xdp: Register generic_kfunc_set with XDP programs
  selftests/bpf: utilize string values for delegate_xxx mount options
  ...
====================

Link: https://lore.kernel.org/r/20231219000520.34178-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

3 files changed, 95 insertions, 0 deletions

diff --git a/fs/verity/fsverity_private.h b/fs/verity/fsverity_private.h
index d071a6e32581..a6a6b2749241 100644
--- a/fs/verity/fsverity_private.h
+++ b/fs/verity/fsverity_private.h
@@ -100,6 +100,16 @@ fsverity_msg(const struct inode *inode, const char *level,
 #define fsverity_err(inode, fmt, ...)		\
 	fsverity_msg((inode), KERN_ERR, fmt, ##__VA_ARGS__)
 
+/* measure.c */
+
+#ifdef CONFIG_BPF_SYSCALL
+void __init fsverity_init_bpf(void);
+#else
+static inline void fsverity_init_bpf(void)
+{
+}
+#endif
+
 /* open.c */
 
 int fsverity_init_merkle_tree_params(struct merkle_tree_params *params,
diff --git a/fs/verity/init.c b/fs/verity/init.c
index a29f062f6047..1e207c0f71de 100644
--- a/fs/verity/init.c
+++ b/fs/verity/init.c
@@ -69,6 +69,7 @@ static int __init fsverity_init(void)
 	fsverity_init_workqueue();
 	fsverity_init_sysctl();
 	fsverity_init_signature();
+	fsverity_init_bpf();
 	return 0;
 }
 late_initcall(fsverity_init)
diff --git a/fs/verity/measure.c b/fs/verity/measure.c
index eec5956141da..bf7a5f4cccaf 100644
--- a/fs/verity/measure.c
+++ b/fs/verity/measure.c
@@ -7,6 +7,8 @@
 
 #include "fsverity_private.h"
 
+#include <linux/bpf.h>
+#include <linux/btf.h>
 #include <linux/uaccess.h>
 
 /**
@@ -100,3 +102,85 @@ int fsverity_get_digest(struct inode *inode,
 	return hash_alg->digest_size;
 }
 EXPORT_SYMBOL_GPL(fsverity_get_digest);
+
+#ifdef CONFIG_BPF_SYSCALL
+
+/* bpf kfuncs */
+__bpf_kfunc_start_defs();
+
+/**
+ * bpf_get_fsverity_digest: read fsverity digest of file
+ * @file: file to get digest from
+ * @digest_ptr: (out) dynptr for struct fsverity_digest
+ *
+ * Read fsverity_digest of *file* into *digest_ptr*.
+ *
+ * Return: 0 on success, a negative value on error.
+ */
+__bpf_kfunc int bpf_get_fsverity_digest(struct file *file, struct bpf_dynptr_kern *digest_ptr)
+{
+	const struct inode *inode = file_inode(file);
+	u32 dynptr_sz = __bpf_dynptr_size(digest_ptr);
+	struct fsverity_digest *arg;
+	const struct fsverity_info *vi;
+	const struct fsverity_hash_alg *hash_alg;
+	int out_digest_sz;
+
+	if (dynptr_sz < sizeof(struct fsverity_digest))
+		return -EINVAL;
+
+	arg = __bpf_dynptr_data_rw(digest_ptr, dynptr_sz);
+	if (!arg)
+		return -EINVAL;
+
+	if (!IS_ALIGNED((uintptr_t)arg, __alignof__(*arg)))
+		return -EINVAL;
+
+	vi = fsverity_get_info(inode);
+	if (!vi)
+		return -ENODATA; /* not a verity file */
+
+	hash_alg = vi->tree_params.hash_alg;
+
+	arg->digest_algorithm = hash_alg - fsverity_hash_algs;
+	arg->digest_size = hash_alg->digest_size;
+
+	out_digest_sz = dynptr_sz - sizeof(struct fsverity_digest);
+
+	/* copy digest */
+	memcpy(arg->digest, vi->file_digest,  min_t(int, hash_alg->digest_size, out_digest_sz));
+
+	/* fill the extra buffer with zeros */
+	if (out_digest_sz > hash_alg->digest_size)
+		memset(arg->digest + arg->digest_size, 0, out_digest_sz - hash_alg->digest_size);
+
+	return 0;
+}
+
+__bpf_kfunc_end_defs();
+
+BTF_SET8_START(fsverity_set_ids)
+BTF_ID_FLAGS(func, bpf_get_fsverity_digest, KF_TRUSTED_ARGS)
+BTF_SET8_END(fsverity_set_ids)
+
+static int bpf_get_fsverity_digest_filter(const struct bpf_prog *prog, u32 kfunc_id)
+{
+	if (!btf_id_set8_contains(&fsverity_set_ids, kfunc_id))
+		return 0;
+
+	/* Only allow to attach from LSM hooks, to avoid recursion */
+	return prog->type != BPF_PROG_TYPE_LSM ? -EACCES : 0;
+}
+
+static const struct btf_kfunc_id_set bpf_fsverity_set = {
+	.owner = THIS_MODULE,
+	.set = &fsverity_set_ids,
+	.filter = bpf_get_fsverity_digest_filter,
+};
+
+void __init fsverity_init_bpf(void)
+{
+	register_btf_kfunc_id_set(BPF_PROG_TYPE_LSM, &bpf_fsverity_set);
+}
+
+#endif /* CONFIG_BPF_SYSCALL */