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 --- Documentation/admin-guide/jfs.rst | 66 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) create mode 100644 Documentation/admin-guide/jfs.rst (limited to 'Documentation/admin-guide/jfs.rst') diff --git a/Documentation/admin-guide/jfs.rst b/Documentation/admin-guide/jfs.rst new file mode 100644 index 000000000..9e12d936b --- /dev/null +++ b/Documentation/admin-guide/jfs.rst @@ -0,0 +1,66 @@ +=========================================== +IBM's Journaled File System (JFS) for Linux +=========================================== + +JFS Homepage: http://jfs.sourceforge.net/ + +The following mount options are supported: + +(*) == default + +iocharset=name + Character set to use for converting from Unicode to + ASCII. The default is to do no conversion. Use + iocharset=utf8 for UTF-8 translations. This requires + CONFIG_NLS_UTF8 to be set in the kernel .config file. + iocharset=none specifies the default behavior explicitly. + +resize=value + Resize the volume to blocks. JFS only supports + growing a volume, not shrinking it. This option is only + valid during a remount, when the volume is mounted + read-write. The resize keyword with no value will grow + the volume to the full size of the partition. + +nointegrity + Do not write to the journal. The primary use of this option + is to allow for higher performance when restoring a volume + from backup media. The integrity of the volume is not + guaranteed if the system abnormally abends. + +integrity(*) + Commit metadata changes to the journal. Use this option to + remount a volume where the nointegrity option was + previously specified in order to restore normal behavior. + +errors=continue + Keep going on a filesystem error. +errors=remount-ro(*) + Remount the filesystem read-only on an error. +errors=panic + Panic and halt the machine if an error occurs. + +uid=value + Override on-disk uid with specified value +gid=value + Override on-disk gid with specified value +umask=value + Override on-disk umask with specified octal value. For + directories, the execute bit will be set if the corresponding + read bit is set. + +discard=minlen, discard/nodiscard(*) + This enables/disables the use of discard/TRIM commands. + The discard/TRIM commands are sent to the underlying + block device when blocks are freed. This is useful for SSD + devices and sparse/thinly-provisioned LUNs. The FITRIM ioctl + command is also available together with the nodiscard option. + The value of minlen specifies the minimum blockcount, when + a TRIM command to the block device is considered useful. + When no value is given to the discard option, it defaults to + 64 blocks, which means 256KiB in JFS. + The minlen value of discard overrides the minlen value given + on an FITRIM ioctl(). + +The JFS mailing list can be subscribed to by using the link labeled +"Mail list Subscribe" at our web page http://jfs.sourceforge.net/ -- cgit v1.3.1