kernel/git/stable/linux-stable.git/fs/libfs.c, branch linux-4.19.y

libfs: add DEFINE_SIMPLE_ATTRIBUTE_SIGNED for signed value

2023-01-18T10:30:06+00:00

[ Upstream commit 2e41f274f9aa71cdcc69dc1f26a3f9304a651804 ] Patch series "fix error when writing negative value to simple attribute files". The simple attribute files do not accept a negative value since the commit 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()"), but some attribute files want to accept a negative value. This patch (of 3): The simple attribute files do not accept a negative value since the commit 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()"), so we have to use a 64-bit value to write a negative value. This adds DEFINE_SIMPLE_ATTRIBUTE_SIGNED for a signed value. Link: https://lkml.kernel.org/r/20220919172418.45257-1-akinobu.mita@gmail.com Link: https://lkml.kernel.org/r/20220919172418.45257-2-akinobu.mita@gmail.com Fixes: 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()") Signed-off-by: Akinobu Mita Reported-by: Zhao Gongyi Reviewed-by: David Hildenbrand Reviewed-by: Greg Kroah-Hartman Cc: Alexander Viro Cc: Jonathan Corbet Cc: Oscar Salvador Cc: Rafael J. Wysocki Cc: Shuah Khan Cc: Wei Yongjun Cc: Yicong Yang Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

libfs: fix error cast of negative value in simple_attr_write()

2020-11-24T12:27:23+00:00

[ Upstream commit 488dac0c9237647e9b8f788b6a342595bfa40bda ] The attr->set() receive a value of u64, but simple_strtoll() is used for doing the conversion. It will lead to the error cast if user inputs a negative value. Use kstrtoull() instead of simple_strtoll() to convert a string got from the user to an unsigned value. The former will return '-EINVAL' if it gets a negetive value, but the latter can't handle the situation correctly. Make 'val' unsigned long long as what kstrtoull() takes, this will eliminate the compile warning on no 64-bit architectures. Fixes: f7b88631a897 ("fs/libfs.c: fix simple_attr_write() on 32bit machines") Signed-off-by: Yicong Yang Signed-off-by: Andrew Morton Cc: Al Viro Link: https://lkml.kernel.org/r/1605341356-11872-1-git-send-email-yangyicong@hisilicon.com Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

libfs: fix infoleak in simple_attr_read()

2020-04-02T13:28:21+00:00

commit a65cab7d7f05c2061a3e2490257d3086ff3202c6 upstream. Reading from a debugfs file at a nonzero position, without first reading at position 0, leaks uninitialized memory to userspace. It's a bit tricky to do this, since lseek() and pread() aren't allowed on these files, and write() doesn't update the position on them. But writing to them with splice() *does* update the position: #define _GNU_SOURCE 1 #include #include #include int main() { int pipes[2], fd, n, i; char buf[32]; pipe(pipes); write(pipes[1], "0", 1); fd = open("/sys/kernel/debug/fault_around_bytes", O_RDWR); splice(pipes[0], NULL, fd, NULL, 1, 0); n = read(fd, buf, sizeof(buf)); for (i = 0; i < n; i++) printf("%02x", buf[i]); printf("\n"); } Output: 5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a30 Fix the infoleak by making simple_attr_read() always fill simple_attr::get_buf if it hasn't been filled yet. Reported-by: syzbot+fcab69d1ada3e8d6f06b@syzkaller.appspotmail.com Reported-by: Alexander Potapenko Fixes: acaefc25d21f ("[PATCH] libfs: add simple attribute files") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Acked-by: Kees Cook Link: https://lore.kernel.org/r/20200308023849.988264-1-ebiggers@kernel.org Signed-off-by: Greg Kroah-Hartman

Fix the locking in dcache_readdir() and friends

2019-10-17T20:45:35+00:00

commit d4f4de5e5ef8efde85febb6876cd3c8ab1631999 upstream. There are two problems in dcache_readdir() - one is that lockless traversal of the list needs non-trivial cooperation of d_alloc() (at least a switch to list_add_rcu(), and probably more than just that) and another is that it assumes that no removal will happen without the directory locked exclusive. Said assumption had always been there, never had been stated explicitly and is violated by several places in the kernel (devpts and selinuxfs). * replacement of next_positive() with different calling conventions: it returns struct list_head * instead of struct dentry *; the latter is passed in and out by reference, grabbing the result and dropping the original value. * scan is under ->d_lock. If we run out of timeslice, cursor is moved after the last position we'd reached and we reschedule; then the scan continues from that place. To avoid livelocks between multiple lseek() (with cursors getting moved past each other, never reaching the real entries) we always skip the cursors, need_resched() or not. * returned list_head * is either ->d_child of dentry we'd found or ->d_subdirs of parent (if we got to the end of the list). * dcache_readdir() and dcache_dir_lseek() switched to new helper. dcache_readdir() always holds a reference to dentry passed to dir_emit() now. Cursor is moved to just before the entry where dir_emit() has failed or into the very end of the list, if we'd run out. * move_cursor() eliminated - it had sucky calling conventions and after fixing that it became simply list_move() (in lseek and scan_positives) or list_move_tail() (in readdir). All operations with the list are under ->d_lock now, and we do not depend upon having all file removals done with parent locked exclusive anymore. Cc: stable@vger.kernel.org Reported-by: "zhengbin (A)" Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

fs, dax: prepare for dax-specific address_space_operations

2018-03-30T18:34:55+00:00

In preparation for the dax implementation to start associating dax pages to inodes via page->mapping, we need to provide a 'struct address_space_operations' instance for dax. Define some generic VFS aops helpers for dax. These noop implementations are there in the dax case to prevent the VFS from falling back to operations with page-cache assumptions, dax_writeback_mapping_range() may not be referenced in the FS_DAX=n case. Cc: Jeff Moyer Cc: Ross Zwisler Suggested-by: Matthew Wilcox Suggested-by: Jan Kara Suggested-by: Christoph Hellwig Reviewed-by: Christoph Hellwig Reviewed-by: Jan Kara Suggested-by: Dave Chinner Signed-off-by: Dan Williams

Rename superblock flags (MS_xyz -> SB_xyz)

2017-11-27T21:05:09+00:00

This is a pure automated search-and-replace of the internal kernel superblock flags. The s_flags are now called SB_*, with the names and the values for the moment mirroring the MS_* flags that they're equivalent to. Note how the MS_xyz flags are the ones passed to the mount system call, while the SB_xyz flags are what we then use in sb->s_flags. The script to do this was: # places to look in; re security/*: it generally should *not* be # touched (that stuff parses mount(2) arguments directly), but # there are two places where we really deal with superblock flags. FILES="drivers/mtd drivers/staging/lustre fs ipc mm \ include/linux/fs.h include/uapi/linux/bfs_fs.h \ security/apparmor/apparmorfs.c security/apparmor/include/lib.h" # the list of MS_... constants SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \ DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \ POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \ I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \ ACTIVE NOUSER" SED_PROG= for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done # we want files that contain at least one of MS_..., # with fs/namespace.c and fs/pnode.c excluded. L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c') for f in $L; do sed -i $f $SED_PROG; done Requested-by: Al Viro Signed-off-by: Linus Torvalds

fs: convert __generic_file_fsync to use errseq_t based reporting

2017-07-06T11:02:29+00:00

Many simple, block-based filesystems use generic_file_fsync as their fsync operation. Some others (ext* and fat) also call this function to handle syncing out data. Switch this code over to use errseq_t based error reporting so that all of these filesystems get reliable error reporting via fsync, fdatasync and msync. Signed-off-by: Jeff Layton

fs: check for writeback errors after syncing out buffers in generic_file_fsync

2017-07-06T11:02:21+00:00

ext2 currently does a test+clear of the AS_EIO flag, which is is problematic for some coming changes. What we really need to do instead is call filemap_check_errors in __generic_file_fsync after syncing out the buffers. That will be sufficient for this case, and help other callers detect these errors properly as well. With that, we don't need to twiddle it in ext2. Suggested-by: Jan Kara Signed-off-by: Jeff Layton Reviewed-by: Christoph Hellwig Reviewed-by: Jan Kara Reviewed-by: Matthew Wilcox

fs: constify tree_descr arrays passed to simple_fill_super()

2017-04-27T03:54:06+00:00

simple_fill_super() is passed an array of tree_descr structures which describe the files to create in the filesystem's root directory. Since these arrays are never modified intentionally, they should be 'const' so that they are placed in .rodata and benefit from memory protection. This patch updates the function signature and all users, and also constifies tree_descr.name. Signed-off-by: Eric Biggers Signed-off-by: Al Viro

Merge branch 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2017-03-03T19:38:56+00:00

Pull vfs 'statx()' update from Al Viro. This adds the new extended stat() interface that internally subsumes our previous stat interfaces, and allows user mode to specify in more detail what kind of information it wants. It also allows for some explicit synchronization information to be passed to the filesystem, which can be relevant for network filesystems: is the cached value ok, or do you need open/close consistency, or what? From David Howells. Andreas Dilger points out that the first version of the extended statx interface was posted June 29, 2010: https://www.spinics.net/lists/linux-fsdevel/msg33831.html * 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: statx: Add a system call to make enhanced file info available