29 Jan, 2020
2 commits
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commit 2c6b7bcd747201441923a0d3062577a8d1fbd8f8 upstream.
Commit 8a23eb804ca4 ("Make filldir[64]() verify the directory entry
filename is valid") added some minimal validity checks on the directory
entries passed to filldir[64](). But they really were pretty minimal.This fleshes out at least the name length check: we used to disallow
zero-length names, but really, negative lengths or oevr-long names
aren't ok either. Both could happen if there is some filesystem
corruption going on.Now, most filesystems tend to use just an "unsigned char" or similar for
the length of a directory entry name, so even with a corrupt filesystem
you should never see anything odd like that. But since we then use the
name length to create the directory entry record length, let's make sure
it actually is half-way sensible.Note how POSIX states that the size of a path component is limited by
NAME_MAX, but we actually use PATH_MAX for the check here. That's
because while NAME_MAX is generally the correct maximum name length
(it's 255, for the same old "name length is usually just a byte on
disk"), there's nothing in the VFS layer that really cares.So the real limitation at a VFS layer is the total pathname length you
can pass as a filename: PATH_MAX.Signed-off-by: Linus Torvalds
Signed-off-by: Greg Kroah-Hartman -
commit 3c2659bd1db81ed6a264a9fc6262d51667d655ad upstream.
In commit 9f79b78ef744 ("Convert filldir[64]() from __put_user() to
unsafe_put_user()") I changed filldir to not do individual __put_user()
accesses, but instead use unsafe_put_user() surrounded by the proper
user_access_begin/end() pair.That make them enormously faster on modern x86, where the STAC/CLAC
games make individual user accesses fairly heavy-weight.However, the user_access_begin() range was not really the exact right
one, since filldir() has the unfortunate problem that it needs to not
only fill out the new directory entry, it also needs to fix up the
previous one to contain the proper file offset.It's unfortunate, but the "d_off" field in "struct dirent" is _not_ the
file offset of the directory entry itself - it's the offset of the next
one. So we end up backfilling the offset in the previous entry as we
walk along.But since x86 didn't really care about the exact range, and used to be
the only architecture that did anything fancy in user_access_begin() to
begin with, the filldir[64]() changes did something lazy, and even
commented on it:/*
* Note! This range-checks 'previous' (which may be NULL).
* The real range was checked in getdents
*/
if (!user_access_begin(dirent, sizeof(*dirent)))
goto efault;and it all worked fine.
But now 32-bit ppc is starting to also implement user_access_begin(),
and the fact that we faked the range to only be the (possibly not even
valid) previous directory entry becomes a problem, because ppc32 will
actually be using the range that is passed in for more than just "check
that it's user space".This is a complete rewrite of Christophe's original patch.
By saving off the record length of the previous entry instead of a
pointer to it in the filldir data structures, we can simplify the range
check and the writing of the previous entry d_off field. No need for
any conditionals in the user accesses themselves, although we retain the
conditional EINTR checking for the "was this the first directory entry"
signal handling latency logic.Fixes: 9f79b78ef744 ("Convert filldir[64]() from __put_user() to unsafe_put_user()")
Link: https://lore.kernel.org/lkml/a02d3426f93f7eb04960a4d9140902d278cab0bb.1579697910.git.christophe.leroy@c-s.fr/
Link: https://lore.kernel.org/lkml/408c90c4068b00ea8f1c41cca45b84ec23d4946b.1579783936.git.christophe.leroy@c-s.fr/
Reported-and-tested-by: Christophe Leroy
Signed-off-by: Linus Torvalds
Signed-off-by: Greg Kroah-Hartman
19 Oct, 2019
1 commit
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This was always meant to be a temporary thing, just for testing and to
see if it actually ever triggered.The only thing that reported it was syzbot doing disk image fuzzing, and
then that warning is expected. So let's just remove it before -rc4,
because the extra sanity testing should probably go to -stable, but we
don't want the warning to do so.Reported-by: syzbot+3031f712c7ad5dd4d926@syzkaller.appspotmail.com
Fixes: 8a23eb804ca4 ("Make filldir[64]() verify the directory entry filename is valid")
Signed-off-by: Linus Torvalds
08 Oct, 2019
1 commit
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In commit 9f79b78ef744 ("Convert filldir[64]() from __put_user() to
unsafe_put_user()") I made filldir() use unsafe_put_user(), which
improves code generation on x86 enormously.But because we didn't have a "unsafe_copy_to_user()", the dirent name
copy was also done by hand with unsafe_put_user() in a loop, and it
turns out that a lot of other architectures didn't like that, because
unlike x86, they have various alignment issues.Most non-x86 architectures trap and fix it up, and some (like xtensa)
will just fail unaligned put_user() accesses unconditionally. Which
makes that "copy using put_user() in a loop" not work for them at all.I could make that code do explicit alignment etc, but the architectures
that don't like unaligned accesses also don't really use the fancy
"user_access_begin/end()" model, so they might just use the regular old
__copy_to_user() interface.So this commit takes that looping implementation, turns it into the x86
version of "unsafe_copy_to_user()", and makes other architectures
implement the unsafe copy version as __copy_to_user() (the same way they
do for the other unsafe_xyz() accessor functions).Note that it only does this for the copying _to_ user space, and we
still don't have a unsafe version of copy_from_user().That's partly because we have no current users of it, but also partly
because the copy_from_user() case is slightly different and cannot
efficiently be implemented in terms of a unsafe_get_user() loop (because
gcc can't do asm goto with outputs).It would be trivial to do this using "rep movsb", which would work
really nicely on newer x86 cores, but really badly on some older ones.Al Viro is looking at cleaning up all our user copy routines to make
this all a non-issue, but for now we have this simple-but-stupid version
for x86 that works fine for the dirent name copy case because those
names are short strings and we simply don't need anything fancier.Fixes: 9f79b78ef744 ("Convert filldir[64]() from __put_user() to unsafe_put_user()")
Reported-by: Guenter Roeck
Reported-and-tested-by: Tony Luck
Cc: Al Viro
Cc: Max Filippov
Signed-off-by: Linus Torvalds
06 Oct, 2019
2 commits
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This has been discussed several times, and now filesystem people are
talking about doing it individually at the filesystem layer, so head
that off at the pass and just do it in getdents{64}().This is partially based on a patch by Jann Horn, but checks for NUL
bytes as well, and somewhat simplified.There's also commentary about how it might be better if invalid names
due to filesystem corruption don't cause an immediate failure, but only
an error at the end of the readdir(), so that people can still see the
filenames that are ok.There's also been discussion about just how much POSIX strictly speaking
requires this since it's about filesystem corruption. It's really more
"protect user space from bad behavior" as pointed out by Jann. But
since Eric Biederman looked up the POSIX wording, here it is for context:"From readdir:
The readdir() function shall return a pointer to a structure
representing the directory entry at the current position in the
directory stream specified by the argument dirp, and position the
directory stream at the next entry. It shall return a null pointer
upon reaching the end of the directory stream. The structure dirent
defined in the header describes a directory entry.From definitions:
3.129 Directory Entry (or Link)
An object that associates a filename with a file. Several directory
entries can associate names with the same file....
3.169 Filename
A name consisting of 1 to {NAME_MAX} bytes used to name a file. The
characters composing the name may be selected from the set of all
character values excluding the slash character and the null byte. The
filenames dot and dot-dot have special meaning. A filename is
sometimes referred to as a 'pathname component'."Note that I didn't bother adding the checks to any legacy interfaces
that nobody uses.Also note that if this ends up being noticeable as a performance
regression, we can fix that to do a much more optimized model that
checks for both NUL and '/' at the same time one word at a time.We haven't really tended to optimize 'memchr()', and it only checks for
one pattern at a time anyway, and we really _should_ check for NUL too
(but see the comment about "soft errors" in the code about why it
currently only checks for '/')See the CONFIG_DCACHE_WORD_ACCESS case of hash_name() for how the name
lookup code looks for pathname terminating characters in parallel.Link: https://lore.kernel.org/lkml/20190118161440.220134-2-jannh@google.com/
Cc: Alexander Viro
Cc: Jann Horn
Cc: Eric W. Biederman
Signed-off-by: Linus Torvalds -
We really should avoid the "__{get,put}_user()" functions entirely,
because they can easily be mis-used and the original intent of being
used for simple direct user accesses no longer holds in a post-SMAP/PAN
world.Manually optimizing away the user access range check makes no sense any
more, when the range check is generally much cheaper than the "enable
user accesses" code that the __{get,put}_user() functions still need.So instead of __put_user(), use the unsafe_put_user() interface with
user_access_{begin,end}() that really does generate better code these
days, and which is generally a nicer interface. Under some loads, the
multiple user writes that filldir() does are actually quite noticeable.This also makes the dirent name copy use unsafe_put_user() with a couple
of macros. We do not want to make function calls with SMAP/PAN
disabled, and the code this generates is quite good when the
architecture uses "asm goto" for unsafe_put_user() like x86 does.Note that this doesn't bother with the legacy cases. Nobody should use
them anyway, so performance doesn't really matter there.Signed-off-by: Linus Torvalds
04 Jan, 2019
1 commit
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Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.Signed-off-by: Linus Torvalds
03 Apr, 2018
1 commit
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Using this helper allows us to avoid the in-kernel calls to the
sys_getdents64() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it
uses the same calling convention as sys_getdents64().This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.netCc: Alexander Viro
Signed-off-by: Dominik Brodowski
07 Nov, 2017
1 commit
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Conflicts:
include/linux/compiler-clang.h
include/linux/compiler-gcc.h
include/linux/compiler-intel.h
include/uapi/linux/stddef.hSigned-off-by: Ingo Molnar
02 Nov, 2017
1 commit
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Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.By default all files without license information are under the default
license of the kernel, which is GPL version 2.Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if
Reviewed-by: Philippe Ombredanne
Reviewed-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
10 Oct, 2017
1 commit
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There was mutex_lock_interruptible() initially, and it was changed
to rwsem, but there were not killable rwsem primitives that time.
>From commit 9902af79c01a:"The main issue is the lack of down_write_killable(), so the places
like readdir.c switched to plain inode_lock(); once killable
variants of rwsem primitives appear, that'll be dealt with"Use down_read_killable() same as down_write_killable() in !shared
case, as concurrent inode_lock() may take much time, that may be
wanted to be interrupted by user.Signed-off-by: Kirill Tkhai
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: arnd@arndb.de
Cc: avagin@virtuozzo.com
Cc: davem@davemloft.net
Cc: fenghua.yu@intel.com
Cc: gorcunov@virtuozzo.com
Cc: heiko.carstens@de.ibm.com
Cc: hpa@zytor.com
Cc: ink@jurassic.park.msu.ru
Cc: mattst88@gmail.com
Cc: rientjes@google.com
Cc: rth@twiddle.net
Cc: schwidefsky@de.ibm.com
Cc: tony.luck@intel.com
Cc: viro@zeniv.linux.org.uk
Link: http://lkml.kernel.org/r/150670120820.23930.5455667921545937220.stgit@localhost.localdomain
Signed-off-by: Ingo Molnar
18 Apr, 2017
1 commit
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Signed-off-by: Al Viro
25 Dec, 2016
1 commit
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This was entirely automated, using the script by Al:
PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*'
sed -i -e "s!$PATT!#include !" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)to do the replacement at the end of the merge window.
Requested-by: Al Viro
Signed-off-by: Linus Torvalds
26 May, 2016
1 commit
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The ones that are taking it exclusive, that is...
Signed-off-by: Al Viro
25 May, 2016
1 commit
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Pull ext4 updates from Ted Ts'o:
"Fix a number of bugs, most notably a potential stale data exposure
after a crash and a potential BUG_ON crash if a file has the data
journalling flag enabled while it has dirty delayed allocation blocks
that haven't been written yet. Also fix a potential crash in the new
project quota code and a maliciously corrupted file system.In addition, fix some DAX-specific bugs, including when there is a
transient ENOSPC situation and races between writes via direct I/O and
an mmap'ed segment that could lead to lost I/O.Finally the usual set of miscellaneous cleanups"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (23 commits)
ext4: pre-zero allocated blocks for DAX IO
ext4: refactor direct IO code
ext4: fix race in transient ENOSPC detection
ext4: handle transient ENOSPC properly for DAX
dax: call get_blocks() with create == 1 for write faults to unwritten extents
ext4: remove unmeetable inconsisteny check from ext4_find_extent()
jbd2: remove excess descriptions for handle_s
ext4: remove unnecessary bio get/put
ext4: silence UBSAN in ext4_mb_init()
ext4: address UBSAN warning in mb_find_order_for_block()
ext4: fix oops on corrupted filesystem
ext4: fix check of dqget() return value in ext4_ioctl_setproject()
ext4: clean up error handling when orphan list is corrupted
ext4: fix hang when processing corrupted orphaned inode list
ext4: remove trailing \n from ext4_warning/ext4_error calls
ext4: fix races between changing inode journal mode and ext4_writepages
ext4: handle unwritten or delalloc buffers before enabling data journaling
ext4: fix jbd2 handle extension in ext4_ext_truncate_extend_restart()
ext4: do not ask jbd2 to write data for delalloc buffers
jbd2: add support for avoiding data writes during transaction commits
...
03 May, 2016
3 commits
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New method: ->iterate_shared(). Same arguments as in ->iterate(),
called with the directory locked only shared. Once all filesystems
switch, the old one will be gone.Signed-off-by: Al Viro
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same as read() on regular files has, and for the same reason.
Signed-off-by: Al Viro
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ta-da!
The main issue is the lack of down_write_killable(), so the places
like readdir.c switched to plain inode_lock(); once killable
variants of rwsem primitives appear, that'll be dealt with.lockdep side also might need more work
Signed-off-by: Al Viro
24 Apr, 2016
1 commit
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If a directory has a large number of empty blocks, iterating over all
of them can take a long time, leading to scheduler warnings and users
getting irritated when they can't kill a process in the middle of one
of these long-running readdir operations. Fix this by adding checks to
ext4_readdir() and ext4_htree_fill_tree().This was reverted earlier due to a typo in the original commit where I
experimented with using signal_pending() instead of
fatal_signal_pending(). The test was in the wrong place if we were
going to return signal_pending() since we would end up returning
duplicant entries. See 9f2394c9be47 for a more detailed explanation.Added fix as suggested by Linus to check for signal_pending() in
in the filldir() functions.Reported-by: Benjamin LaHaise
Google-Bug-Id: 27880676
Signed-off-by: Theodore Ts'o
23 Jan, 2016
1 commit
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parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.Signed-off-by: Al Viro
01 Nov, 2014
1 commit
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Signed-off-by: Miklos Szeredi
Signed-off-by: Al Viro
05 Jun, 2014
1 commit
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Before the patch, read creates FAN_ACCESS_PERM and FAN_ACCESS events,
readdir creates only FAN_ACCESS_PERM events.This is inconsistent.
After the patch, readdir creates FAN_ACCESS_PERM and FAN_ACCESS events.
Signed-off-by: Heinrich Schuchardt
Reviewed-by: Jan Kara
Cc: Eric Paris
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
25 Oct, 2013
1 commit
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Signed-off-by: Al Viro
29 Jun, 2013
4 commits
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Signed-off-by: Al Viro
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everything's converted to ->iterate()
Signed-off-by: Al Viro
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New method - ->iterate(file, ctx). That's the replacement for ->readdir();
it takes callback from ctx->actor, uses ctx->pos instead of file->f_pos and
calls dir_emit(ctx, ...) instead of filldir(data, ...). It does *not*
update file->f_pos (or look at it, for that matter); iterate_dir() does the
update.Note that dir_emit() takes the offset from ctx->pos (and eventually
filldir_t will lose that argument).Signed-off-by: Al Viro
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iterate_dir(): new helper, replacing vfs_readdir().
struct dir_context: contains the readdir callback (and will get more stuff
in it), embedded into whatever data that callback wants to deal with;
eventually, we'll be passing it to ->readdir() replacement instead of
(data,filldir) pair.Signed-off-by: Al Viro
23 Feb, 2013
1 commit
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Signed-off-by: Al Viro
27 Sep, 2012
1 commit
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Signed-off-by: Al Viro
30 May, 2012
1 commit
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Signed-off-by: Al Viro
29 Feb, 2012
1 commit
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For files only using THIS_MODULE and/or EXPORT_SYMBOL, map
them onto including export.h -- or if the file isn't even
using those, then just delete the include. Fix up any implicit
include dependencies that were being masked by module.h along
the way.Signed-off-by: Paul Gortmaker
10 Aug, 2010
1 commit
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Using:
gcc (GCC) 4.5.0 20100610 (prerelease)
The following warnings appear:
fs/readdir.c: In function `filldir64':
fs/readdir.c:240:15: warning: `dirent' is used uninitialized in this function
fs/readdir.c: In function `filldir':
fs/readdir.c:155:15: warning: `dirent' is used uninitialized in this function
fs/compat.c: In function `compat_filldir64':
fs/compat.c:1071:11: warning: `dirent' is used uninitialized in this function
fs/compat.c: In function `compat_filldir':
fs/compat.c:984:15: warning: `dirent' is used uninitialized in this functionThe warnings are related to the use of the NAME_OFFSET() macro. Luckily,
it appears as though the standard offsetof() macro is what is being
implemented by NAME_OFFSET(), thus we can fix the warning and use a more
standard code construct at the same time.Signed-off-by: Kevin Winchester
Cc: Al Viro
Cc: Christoph Hellwig
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
14 Jan, 2009
3 commits
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Signed-off-by: Heiko Carstens
-
Signed-off-by: Heiko Carstens
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This way it matches the generic system call name convention.
Signed-off-by: Heiko Carstens
23 Oct, 2008
1 commit
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It's not the final state, but it allows moving ->readdir() instances
to passing filldir return value to caller of vfs_readdir().Signed-off-by: Al Viro
25 Aug, 2008
1 commit
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Handling of -EOVERFLOW.
Signed-off-by: Al Viro
07 Dec, 2007
1 commit
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Signed-off-by: Liam R. Howlett
Acked-by: Ingo Molnar
Signed-off-by: Matthew Wilcox
09 May, 2007
2 commits
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ROUND_UP macro cleanup use,ALIGN or DIV_ROUND_UP where ever appropriate.
Signed-off-by: Milind Arun Choudhary
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Remove includes of where it is not used/needed.
Suggested by Al Viro.Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).Signed-off-by: Randy Dunlap
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
