From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly. l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries. A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly. This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context. Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT. [shorne@gmail.com: fix comment style] Fixes: 9d02a4283e9c ("OpenRISC: Boot code") Cc: stable@vger.kernel.org Signed-off-by: Ali Ahmet Memis Signed-off-by: Stafford Horne --- fs/udf/udftime.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 89 insertions(+) create mode 100644 fs/udf/udftime.c (limited to 'fs/udf/udftime.c') diff --git a/fs/udf/udftime.c b/fs/udf/udftime.c new file mode 100644 index 000000000..78ecc6336 --- /dev/null +++ b/fs/udf/udftime.c @@ -0,0 +1,89 @@ +// SPDX-License-Identifier: LGPL-2.0+ +/* Copyright (C) 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Paul Eggert (eggert@twinsun.com). */ + +/* + * dgb 10/02/98: ripped this from glibc source to help convert timestamps + * to unix time + * 10/04/98: added new table-based lookup after seeing how ugly + * the gnu code is + * blf 09/27/99: ripped out all the old code and inserted new table from + * John Brockmeyer (without leap second corrections) + * rewrote udf_stamp_to_time and fixed timezone accounting in + * udf_time_to_stamp. + */ + +/* + * We don't take into account leap seconds. This may be correct or incorrect. + * For more NIST information (especially dealing with leap seconds), see: + * http://www.boulder.nist.gov/timefreq/pubs/bulletin/leapsecond.htm + */ + +#include "udfdecl.h" + +#include +#include +#include + +void +udf_disk_stamp_to_time(struct timespec64 *dest, struct timestamp src) +{ + u16 typeAndTimezone = le16_to_cpu(src.typeAndTimezone); + u16 year = le16_to_cpu(src.year); + uint8_t type = typeAndTimezone >> 12; + int16_t offset; + + if (type == 1) { + offset = typeAndTimezone << 4; + /* sign extent offset */ + offset = (offset >> 4); + if (offset == -2047) /* unspecified offset */ + offset = 0; + } else + offset = 0; + + dest->tv_sec = mktime64(year, src.month, src.day, src.hour, src.minute, + src.second); + dest->tv_sec -= offset * 60; + + /* + * Sanitize nanosecond field since reportedly some filesystems are + * recorded with bogus sub-second values. + */ + if (src.centiseconds < 100 && src.hundredsOfMicroseconds < 100 && + src.microseconds < 100) { + dest->tv_nsec = 1000 * (src.centiseconds * 10000 + + src.hundredsOfMicroseconds * 100 + src.microseconds); + } else { + dest->tv_nsec = 0; + } +} + +void +udf_time_to_disk_stamp(struct timestamp *dest, struct timespec64 ts) +{ + time64_t seconds; + int16_t offset; + struct tm tm; + + offset = -sys_tz.tz_minuteswest; + + dest->typeAndTimezone = cpu_to_le16(0x1000 | (offset & 0x0FFF)); + + seconds = ts.tv_sec + offset * 60; + time64_to_tm(seconds, 0, &tm); + dest->year = cpu_to_le16(tm.tm_year + 1900); + dest->month = tm.tm_mon + 1; + dest->day = tm.tm_mday; + dest->hour = tm.tm_hour; + dest->minute = tm.tm_min; + dest->second = tm.tm_sec; + dest->centiseconds = ts.tv_nsec / 10000000; + dest->hundredsOfMicroseconds = (ts.tv_nsec / 1000 - + dest->centiseconds * 10000) / 100; + dest->microseconds = (ts.tv_nsec / 1000 - dest->centiseconds * 10000 - + dest->hundredsOfMicroseconds * 100); +} + +/* EOF */ -- cgit v1.3.1