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/ntfs/time.h | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 fs/ntfs/time.h (limited to 'fs/ntfs/time.h') diff --git a/fs/ntfs/time.h b/fs/ntfs/time.h new file mode 100644 index 000000000..aeed195bd --- /dev/null +++ b/fs/ntfs/time.h @@ -0,0 +1,87 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * NTFS time conversion functions. + * + * Copyright (c) 2001-2005 Anton Altaparmakov + */ + +#ifndef _LINUX_NTFS_TIME_H +#define _LINUX_NTFS_TIME_H + +#include +#include /* For do_div(). */ + +#define NTFS_TIME_OFFSET ((s64)(369 * 365 + 89) * 24 * 3600) + +/* + * utc2ntfs - convert Linux UTC time to NTFS time + * @ts: Linux UTC time to convert to NTFS time + * + * Convert the Linux UTC time @ts to its corresponding NTFS time and return + * that in little endian format. + * + * Linux stores time in a struct timespec64 consisting of a time64_t tv_sec + * and a long tv_nsec where tv_sec is the number of 1-second intervals since + * 1st January 1970, 00:00:00 UTC and tv_nsec is the number of 1-nano-second + * intervals since the value of tv_sec. + * + * NTFS uses Microsoft's standard time format which is stored in a s64 and is + * measured as the number of 100-nano-second intervals since 1st January 1601, + * 00:00:00 UTC. + */ +static inline __le64 utc2ntfs(const struct timespec64 ts) +{ + /* + * Convert the seconds to 100ns intervals, add the nano-seconds + * converted to 100ns intervals, and then add the NTFS time offset. + */ + return cpu_to_le64((u64)(ts.tv_sec + NTFS_TIME_OFFSET) * 10000000 + + ts.tv_nsec / 100); +} + +/* + * get_current_ntfs_time - get the current time in little endian NTFS format + * + * Get the current time from the Linux kernel, convert it to its corresponding + * NTFS time and return that in little endian format. + */ +static inline __le64 get_current_ntfs_time(void) +{ + struct timespec64 ts; + + ktime_get_coarse_real_ts64(&ts); + return utc2ntfs(ts); +} + +/* + * ntfs2utc - convert NTFS time to Linux time + * @time: NTFS time (little endian) to convert to Linux UTC + * + * Convert the little endian NTFS time @time to its corresponding Linux UTC + * time and return that in cpu format. + * + * Linux stores time in a struct timespec64 consisting of a time64_t tv_sec + * and a long tv_nsec where tv_sec is the number of 1-second intervals since + * 1st January 1970, 00:00:00 UTC and tv_nsec is the number of 1-nano-second + * intervals since the value of tv_sec. + * + * NTFS uses Microsoft's standard time format which is stored in a s64 and is + * measured as the number of 100 nano-second intervals since 1st January 1601, + * 00:00:00 UTC. + */ +static inline struct timespec64 ntfs2utc(const __le64 time) +{ + struct timespec64 ts; + s32 t32; + + /* Subtract the NTFS time offset. */ + s64 t = le64_to_cpu(time) - NTFS_TIME_OFFSET * 10000000; + /* + * Convert the time to 1-second intervals and the remainder to + * 1-nano-second intervals. + */ + ts.tv_sec = div_s64_rem(t, 10000000, &t32); + ts.tv_nsec = t32 * 100; + return ts; +} +#endif /* _LINUX_NTFS_TIME_H */ -- cgit v1.3.1