From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- fs/verity/init.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 fs/verity/init.c (limited to 'fs/verity/init.c') diff --git a/fs/verity/init.c b/fs/verity/init.c new file mode 100644 index 000000000..3aa55dec8 --- /dev/null +++ b/fs/verity/init.c @@ -0,0 +1,70 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * fs-verity module initialization and logging + * + * Copyright 2019 Google LLC + */ + +#define CREATE_TRACE_POINTS +#include "fsverity_private.h" + +#include + +#ifdef CONFIG_SYSCTL +static const struct ctl_table fsverity_sysctl_table[] = { +#ifdef CONFIG_FS_VERITY_BUILTIN_SIGNATURES + { + .procname = "require_signatures", + .data = &fsverity_require_signatures, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE, + }, +#endif +}; + +static void __init fsverity_init_sysctl(void) +{ + register_sysctl_init("fs/verity", fsverity_sysctl_table); +} +#else /* CONFIG_SYSCTL */ +static inline void fsverity_init_sysctl(void) +{ +} +#endif /* !CONFIG_SYSCTL */ + +void fsverity_msg(const struct inode *inode, const char *level, + const char *fmt, ...) +{ + static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL, + DEFAULT_RATELIMIT_BURST); + struct va_format vaf; + va_list args; + + if (!__ratelimit(&rs)) + return; + + va_start(args, fmt); + vaf.fmt = fmt; + vaf.va = &args; + if (inode) + printk("%sfs-verity (%s, inode %llu): %pV\n", + level, inode->i_sb->s_id, inode->i_ino, &vaf); + else + printk("%sfs-verity: %pV\n", level, &vaf); + va_end(args); +} + +static int __init fsverity_init(void) +{ + fsverity_check_hash_algs(); + fsverity_init_info_cache(); + fsverity_init_workqueue(); + fsverity_init_sysctl(); + fsverity_init_signature(); + fsverity_init_bpf(); + return 0; +} +late_initcall(fsverity_init) -- cgit v1.3.1