C99 6.7.8.17 says that when an undesignated initialiser is used, only
the first element of a union is initialised. If the first element is not
the largest within the union, how the remaining space is initialised is
up to the compiler.
GCC extends the initialiser to the entire union, while Clang treats the
remainder as padding, and so initialises according to whatever
automatic/implicit initialisation rules are currently active.
When Linux is compiled with CONFIG_INIT_STACK_ALL_PATTERN,
-ftrivial-auto-var-init=pattern is added to the kernel CFLAGS. This flag
sets the policy for automatic/implicit initialisation of variables on
the stack.
Taken together, this means that when compiling under
CONFIG_INIT_STACK_ALL_PATTERN on Clang, the "zero" initialiser will only
zero the first element in a union, and the rest will be filled with a
pattern. This is significant for aes_ctx_t, which in
aes_encrypt_atomic() and aes_decrypt_atomic() is initialised to zero,
but then used as a gcm_ctx_t, which is the fifth element in the union,
and thus gets pattern initialisation. Later, it's assumed to be zero,
resulting in a hang.
As confusing and undiscoverable as it is, by the spec, we are at fault
when we initialise a structure containing a union with the zero
initializer. As such, this commit replaces these uses with an explicit
memset(0).
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Tino Reichardt <milky-zfs@mcmilk.de>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Closes#16135Closes#16206
In the zstream code, Coverity reported:
"The argument could be controlled by an attacker, who could invoke the
function with arbitrary values (for example, a very high or negative
buffer size)."
It did not report this in the kernel. This is likely because the
userspace code stored this in an int before passing it into the
allocator, while the kernel code stored it in a uint32_t.
However, this did reveal a potentially real problem. On 32-bit systems
and systems with only 4GB of physical memory or less in general, it is
possible to pass a large enough value that the system will hang. Even
worse, on Linux systems, the kernel memory allocator is not able to
support allocations up to the maximum 4GB allocation size that this
allows.
This had already been limited in userspace to 64MB by
`ZFS_SENDRECV_MAX_NVLIST`, but we need a hard limit in the kernel to
protect systems. After some discussion, we settle on 256MB as a hard
upper limit. Attempting to receive a stream that requires more memory
than that will result in E2BIG being returned to user space.
Reported-by: Coverity (CID-1529836)
Reported-by: Coverity (CID-1529837)
Reported-by: Coverity (CID-1529838)
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#14285
Coverity has long complained about the checksum being uninitialized if
an END record is processed before its BEGIN record. This should not
happen, but there was no code to check for it. I had left this unfixed
since it was a low priority issue, but then
9f4ede63d2 added another instance of this.
I am making an effort to "hold the line" to keep new coverity defect
reports from going unaddressed, so I find myself forced to fix this much
earlier than I had originally planned to address it.
The solution is to maintain a counter and a flag. Then use VERIFY
statements to verify the following runtime constraints:
* Every record either has a corresponding BEGIN record, is a BEGIN
record or is the end of stream END record for replication streams.
* BEGIN records cannot be nested. i.e. There must be an END record
before another BEGIN record may be seen.
Failure to meet these constraints will cause the program to exit.
This is sufficient to ensure that the checksum is never accessed when
uninitialized.
Reported-by: Coverity (CID 1524578)
Reported-by: Coverity (CID 1524633)
Reported-by: Coverity (CID 1527295)
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Damian Szuberski <szuberskidamian@gmail.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes#14176
It can be used to repair a ZFS file system corrupted by ZFS bug #12762.
Use it like this:
zfs send -c <DS> | \
zstream decompress <OBJECT>,<OFFSET>[,<COMPRESSION_ALGO>] ... | \
zfs recv <DST_DS>
Reviewed-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Alan Somers <asomers@gmail.com>
Sponsored-by: Axcient
Workaround for #12762Closes#13256
bcopy() has a confusing argument order and is actually a move, not a
copy; they're all deprecated since POSIX.1-2001 and removed in -2008,
and we shim them out to mem*() on Linux anyway
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes#12996
For some reason cppcheck 1.90 is generating an invalidSyntax warning
when the BF64_SET macro is used in the zstream source. The same
warning is not reported by cppcheck 2.3, nor is their any evident
problem with the expanded macro. This appears to be an issue with
this version of cppcheck. This commit annotates the source to suppress
the warning.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11700
Use the correct return type for getopt otherwise clang complains
about tautological-constant-out-of-range-compare.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Sterling Jensen <sterlingjensen@users.noreply.github.com>
Closes#11359
Fix uninitialized variable in `zstream redup` command. The compiler
may determine the 'stream_offset' variable can be uninitialized
because not all rdt_lookup() exit paths set it. This should never
happen in practice as documented by the assert, but initialize it
regardless to resolve the warning.
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#10241Closes#10244
* Fix uninitialized variable in `zstream redup` command. The
'rdt.ddt_count' variable is uninitialized because it was
allocated from the stack and not globally. Initialize it.
This was reported by gcc when compiling with debugging enabled.
zstream_redup.c:157:16: error: 'rdt.ddt_count' may be used
uninitialized in this function [-Werror=maybe-uninitialized]
* Remove the cmd/zstreamdump/.gitignore file. It's no longer
needed now that the zstreamdump command is a script.
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#10192
Deduplicated send and receive is deprecated. To ease migration to the
new dedup-send-less world, the commit adds a `zstream redup` utility to
convert deduplicated send streams to normal streams, so that they can
continue to be received indefinitely.
The new `zstream` command also replaces the functionality of
`zstreamdump`, by way of the `zstream dump` subcommand. The
`zstreamdump` command is replaced by a shell script which invokes
`zstream dump`.
The way that `zstream redup` works under the hood is that as we read the
send stream, we build up a hash table which maps from `<GUID, object,
offset> -> <file_offset>`.
Whenever we see a WRITE record, we add a new entry to the hash table,
which indicates where in the stream file to find the WRITE record for
this block. (The key is `drr_toguid, drr_object, drr_offset`.)
For entries other than WRITE_BYREF, we pass them through unchanged
(except for the running checksum, which is recalculated).
For WRITE_BYREF records, we change them to WRITE records. We find the
referenced WRITE record by looking in the hash table (for the record
with key `drr_refguid, drr_refobject, drr_refoffset`), and then reading
the record header and payload from the specified offset in the stream
file. This is why the stream can not be a pipe. The found WRITE record
replaces the WRITE_BYREF record, with its `drr_toguid`, `drr_object`,
and `drr_offset` fields changed to be the same as the WRITE_BYREF's
(i.e. we are writing the same logical block, but with the data supplied
by the previous WRITE record).
This algorithm requires memory proportional to the number of WRITE
records (same as `zfs send -D`), but the size per WRITE record is
relatively low (40 bytes, vs. 72 for `zfs send -D`). A 1TB send stream
with 8KB blocks (`recordsize=8k`) would use around 5GB of RAM to
"redup".
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Paul Dagnelie <pcd@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10124Closes#10156
Rob N
Richard Yao
Alan Somers
наб
Brian Behlendorf
sterlingjensen
Matthew Ahrens