`snprintf()` is meant to protect against buffer overflows, but operating
on the buffer using its return value, possibly by calling it again, can
cause a buffer overflow, because it will return how many characters it
would have written if it had enough space even when it did not. In a
number of places, we repeatedly call snprintf() by successively
incrementing a buffer offset and decrementing a buffer length, by its
return value. This is a potentially unsafe usage of `snprintf()`
whenever the buffer length is reached. CodeQL complained about this.
To fix this, we introduce `kmem_scnprintf()`, which will return 0 when
the buffer is zero or the number of written characters, minus 1 to
exclude the NULL character, when the buffer was too small. In all other
cases, it behaves like snprintf(). The name is inspired by the Linux and
XNU kernels' `scnprintf()`. The implementation was written before I
thought to look at `scnprintf()` and had a good name for it, but it
turned out to have identical semantics to the Linux kernel version.
That lead to the name, `kmem_scnprintf()`.
CodeQL only catches this issue in loops, so repeated use of snprintf()
outside of a loop was not caught. As a result, a thorough audit of the
codebase was done to examine all instances of `snprintf()` usage for
potential problems and a few were caught. Fixes for them are included in
this patch.
Unfortunately, ZED is one of the places where `snprintf()` is
potentially used incorrectly. Since using `kmem_scnprintf()` in it would
require changing how it is linked, we modify its usage to make it safe,
no matter what buffer length is used. In addition, there was a bug in
the use of the return value where the NULL format character was not
being written by pwrite(). That has been fixed.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#14098
Both Clang's Static Analyzer and Synopsys' Coverity would ignore
assertions. Following Clang's advice, we annotate our assertions:
https://clang-analyzer.llvm.org/annotations.html#custom_assertions
This makes both Clang's Static Analyzer and Coverity properly identify
assertions. This change reduced Clang's reported defects from 246 to
180. It also reduced the false positives reported by Coverityi by 10,
while enabling Coverity to find 9 more defects that previously were
false negatives.
A couple examples of this would be CID-1524417 and CID-1524423. After
submitting a build to coverity with the modified assertions, CID-1524417
disappeared while the report for CID-1524423 no longer claimed that the
assertion tripped.
Coincidentally, it turns out that it is possible to more accurately
annotate our headers than the Coverity modelling file permits in the
case of format strings. Since we can do that and this patch annotates
headers whenever `__coverity_panic__()` would have been used in the
model file, we drop all models that use `__coverity_panic__()` from the
model file.
Upon seeing the success in eliminating false positives involving
assertions, it occurred to me that we could also modify our headers to
eliminate coverity's false positives involving byte swaps. We now have
coverity specific byteswap macros, that do nothing, to disable
Coverity's false positives when we do byte swaps. This allowed us to
also drop the byteswap definitions from the model file.
Lastly, a model file update has been done beyond the mentioned
deletions:
* The definitions of `umem_alloc_aligned()`, `umem_alloc()` andi
`umem_zalloc()` were originally implemented in a way that was
intended to inform coverity that when KM_SLEEP has been passed these
functions, they do not return NULL. A small error in how this was
done was found, so we correct it.
* Definitions for umem_cache_alloc() and umem_cache_free() have been
added.
In practice, no false positives were avoided by making these changes,
but in the interest of correctness from future coverity builds, we make
them anyway.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#13902
In FreeBSD, there are three compile environments that are supported:
user land, the kernel and the bootloader / standalone. Adjust the
headers to compile in the standalone environment. Limit kernel-only
items from view when _STANDALONE is defined.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Warner Losh <imp@FreeBSD.org>
Closes#10998
Remove dead code to make the implementation easier to understand.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Ahrens <matt@delphix.com>
Closes#10650
Remove dead code to make the implementation easier to understand.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Ahrens <matt@delphix.com>
Closes#10650
A collection of header changes to enable FreeBSD to build
with vendored OpenZFS.
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#10635
OS-specific code (e.g. under `module/os/linux`) does not need to share
its code structure with any other operating systems. In particular, the
ARC and kmem code need not be similar to the code in illumos, because we
won't be syncing this OS-specific code between operating systems. For
example, if/when illumos support is added to the common repo, we would
add a file `module/os/illumos/zfs/arc_os.c` for the illumos versions of
this code.
Therefore, we can simplify the code in the OS-specific ARC and kmem
routines.
These changes do not impact system behavior, they are purely code
cleanup. The changes are:
Arenas are not used on Linux or FreeBSD (they are always `NULL`), so
`heap_arena`, `zio_arena`, and `zio_alloc_arena` can be removed, along
with code that uses them.
In `arc_available_memory()`:
* `desfree` is unused, remove it
* rename `freemem` to avoid conflict with pre-existing `#define`
* remove checks related to arenas
* use units of bytes, rather than converting from bytes to pages and
then back to bytes
`SPL_KMEM_CACHE_REAP` is unused, remove it.
`skc_reap` is unused, remove it.
The `count` argument to `spl_kmem_cache_reap_now()` is unused, remove
it.
`vmem_size()` and associated type and macros are unused, remove them.
In `arc_memory_throttle()`, use a less confusing variable name to store
the result of `arc_free_memory()`.
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10499
Add the FreeBSD platform code to the OpenZFS repository. As of this
commit the source can be compiled and tested on FreeBSD 11 and 12.
Subsequent commits are now required to compile on FreeBSD and Linux.
Additionally, they must pass the ZFS Test Suite on FreeBSD which is
being run by the CI. As of this commit 1230 tests pass on FreeBSD
and there are no unexpected failures.
Reviewed-by: Sean Eric Fagan <sef@ixsystems.com>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes#898Closes#8987
