This project might be open to known security vulnerabilities, which can be prevented by tightening the version range of affected dependencies. Find detailed information at the bottom.
Affected versions of the crate did not properly implement a 'static lifetime bound on the waker function.
This resulted in a use-after-free if Waker::wake() is called after original data had been dropped.
The flaw was corrected by adding 'static lifetime bound to the data waker takes.
chrono: Potential segfault in `localtime_r` invocations
Unix-like operating systems may segfault due to dereferencing a dangling pointer in specific circumstances. This requires an environment variable to be set in a different thread than the affected functions. This may occur without the user's knowledge, notably in a third-party library.
A bug in the SmallVec::insert_many method caused it to allocate a buffer that was smaller than needed. It then wrote past the end of the buffer, causing a buffer overflow and memory corruption on the heap.
This bug was only triggered if the iterator passed to insert_many yielded more items than the lower bound returned from its size_hint method.
The flaw was corrected in smallvec 0.6.14 and 1.6.1, by ensuring that additional space is always reserved for each item inserted. The fix also simplified the implementation of insert_many to use less unsafe code, so it is easier to verify its correctness.
Thank you to Yechan Bae (@Qwaz) and the Rust group at Georgia Tech’s SSLab for finding and reporting this bug.
hyper: Lenient `hyper` header parsing of `Content-Length` could allow request smuggling
hyper's HTTP header parser accepted, according to RFC 7230, illegal contents inside Content-Length headers.
Due to this, upstream HTTP proxies that ignore the header may still forward them along if it chooses to ignore the error.
To be vulnerable, hyper must be used as an HTTP/1 server and using an HTTP proxy upstream that ignores the header's contents
but still forwards it. Due to all the factors that must line up, an attack exploiting this vulnerability is unlikely.
hyper: Integer overflow in `hyper`'s parsing of the `Transfer-Encoding` header leads to data loss
When decoding chunk sizes that are too large, hyper's code would encounter an integer overflow. Depending on the situation,
this could lead to data loss from an incorrect total size, or in rarer cases, a request smuggling attack.
To be vulnerable, you must be using hyper for any HTTP/1 purpose, including as a client or server, and consumers must send
requests or responses that specify a chunk size greater than 18 exabytes. For a possible request smuggling attack to be possible,
any upstream proxies must accept a chunk size greater than 64 bits.
tar: Links in archive can create arbitrary directories
When unpacking a tarball that contains a symlink the tar crate may create
directories outside of the directory it's supposed to unpack into.
The function errors when it's trying to create a file, but the folders are
already created at this point.
use std::{io, io::Result};
use tar::{Archive, Builder, EntryType, Header};
fn main() -> Result<()> {
let mut buf = Vec::new();
{
let mut builder = Builder::new(&mut buf);
// symlink: parent -> ..
let mut header = Header::new_gnu();
header.set_path("symlink")?;
header.set_link_name("..")?;
header.set_entry_type(EntryType::Symlink);
header.set_size(0);
header.set_cksum();
builder.append(&header, io::empty())?;
// file: symlink/exploit/foo/bar
let mut header = Header::new_gnu();
header.set_path("symlink/exploit/foo/bar")?;
header.set_size(0);
header.set_cksum();
builder.append(&header, io::empty())?;
builder.finish()?;
};
Archive::new(&*buf).unpack("demo")
}
This has been fixed in https://github.com/alexcrichton/tar-rs/pull/259 and is
published as tar 0.4.36. Thanks to Martin Michaelis (@mgjm) for discovering
and reporting this, and Nikhil Benesch (@benesch) for the fix!
nix: Out-of-bounds write in nix::unistd::getgrouplist
On certain platforms, if a user has more than 16 groups, the
nix::unistd::getgrouplist function will call the libc getgrouplist
function with a length parameter greater than the size of the buffer it
provides, resulting in an out-of-bounds write and memory corruption.
The libc getgrouplist function takes an in/out parameter ngroups
specifying the size of the group buffer. When the buffer is too small to
hold all of the requested user's group memberships, some libc
implementations, including glibc and Solaris libc, will modify ngroups
to indicate the actual number of groups for the user, in addition to
returning an error. The version of nix::unistd::getgrouplist in nix
0.16.0 and up will resize the buffer to twice its size, but will not
read or modify the ngroups variable. Thus, if the user has more than
twice as many groups as the initial buffer size of 8, the next call to
getgrouplist will then write past the end of the buffer.
The issue would require editing /etc/groups to exploit, which is usually
only editable by the root user.
regex: Regexes with large repetitions on empty sub-expressions take a very long time to parse
The Rust Security Response WG was notified that the regex crate did not
properly limit the complexity of the regular expressions (regex) it parses. An
attacker could use this security issue to perform a denial of service, by
sending a specially crafted regex to a service accepting untrusted regexes. No
known vulnerability is present when parsing untrusted input with trusted
regexes.
This issue has been assigned CVE-2022-24713. The severity of this vulnerability
is "high" when the regex crate is used to parse untrusted regexes. Other uses
of the regex crate are not affected by this vulnerability.
Overview
The regex crate features built-in mitigations to prevent denial of service
attacks caused by untrusted regexes, or untrusted input matched by trusted
regexes. Those (tunable) mitigations already provide sane defaults to prevent
attacks. This guarantee is documented and it's considered part of the crate's
API.
Unfortunately a bug was discovered in the mitigations designed to prevent
untrusted regexes to take an arbitrary amount of time during parsing, and it's
possible to craft regexes that bypass such mitigations. This makes it possible
to perform denial of service attacks by sending specially crafted regexes to
services accepting user-controlled, untrusted regexes.
Affected versions
All versions of the regex crate before or equal to 1.5.4 are affected by this
issue. The fix is include starting from regex 1.5.5.
Mitigations
We recommend everyone accepting user-controlled regexes to upgrade immediately
to the latest version of the regex crate.
Unfortunately there is no fixed set of problematic regexes, as there are
practically infinite regexes that could be crafted to exploit this
vulnerability. Because of this, we do not recommend denying known problematic
regexes.
Acknowledgements
We want to thank Addison Crump for responsibly disclosing this to us according
to the Rust security policy, and for helping review the fix.
We also want to thank Andrew Gallant for developing the fix, and Pietro Albini
for coordinating the disclosure and writing this advisory.
When using named pipes on Windows, mio will under some circumstances return invalid tokens that correspond to named pipes that have already been deregistered from the mio registry. The impact of this vulnerability depends on how mio is used. For some applications, invalid tokens may be ignored or cause a warning or a crash. On the other hand, for applications that store pointers in the tokens, this vulnerability may result in a use-after-free.
For users of Tokio, this vulnerability is serious and can result in a use-after-free in Tokio.
The vulnerability is Windows-specific, and can only happen if you are using named pipes. Other IO resources are not affected.
Affected versions
This vulnerability has been fixed in mio v0.8.11.
All versions of mio between v0.7.2 and v0.8.10 are vulnerable.
Tokio is vulnerable when you are using a vulnerable version of mio AND you are using at least Tokio v1.30.0. Versions of Tokio prior to v1.30.0 will ignore invalid tokens, so they are not vulnerable.
Workarounds
Vulnerable libraries that use mio can work around this issue by detecting and ignoring invalid tokens.
Technical details
When an IO resource registered with mio has a readiness event, mio delivers that readiness event to the user using a user-specified token. Mio guarantees that when an IO resource is deregistered, then it will never return the token for that IO resource again. However, for named pipes on windows, mio may sometimes deliver the token for a named pipe even though the named pipe has been previously deregistered.
With versions of the whoami crate >= 0.5.3 and < 1.5.0, calling any of these functions leads to an
immediate stack buffer overflow on illumos and Solaris:
whoami::username
whoami::realname
whoami::username_os
whoami::realname_os
With versions of the whoami crate >= 0.5.3 and < 1.0.1, calling any of the above functions also
leads to a stack buffer overflow on these platforms:
Bitrig
DragonFlyBSD
FreeBSD
NetBSD
OpenBSD
This occurs because of an incorrect definition of the passwd struct on those platforms.
As a result of this issue, denial of service and data corruption have both been observed in the
wild. The issue is possibly exploitable as well.
This vulnerability also affects other Unix platforms that aren't Linux or macOS.
Essentially, encoding a value larger than 4GiB can cause the length prefix in the protocol to overflow,
causing the server to interpret the rest of the string as binary protocol commands or other data.
This code has existed essentially since the beginning,
so it is reasonable to assume that all published versions <= 0.8.0 are affected.
Mitigation
As always, you should make sure your application is validating untrustworthy user input.
Reject any input over 4 GiB, or any input that could encode to a string longer than 4 GiB.
Dynamically built queries are also potentially problematic if it pushes the message size over this 4 GiB bound.
Encode::size_hint()
can be used for sanity checks, but do not assume that the size returned is accurate.
For example, the Json<T> and Text<T> adapters have no reasonable way to predict or estimate the final encoded size,
so they just return size_of::<T>() instead.
For web application backends, consider adding some middleware that limits the size of request bodies by default.
ring::aead::quic::HeaderProtectionKey::new_mask() may panic when overflow
checking is enabled. In the QUIC protocol, an attacker can induce this panic by
sending a specially-crafted packet. Even unintentionally it is likely to occur
in 1 out of every 2**32 packets sent and/or received.
On 64-bit targets operations using ring::aead::{AES_128_GCM, AES_256_GCM} may
panic when overflow checking is enabled, when encrypting/decrypting approximately
68,719,476,700 bytes (about 64 gigabytes) of data in a single chunk. Protocols
like TLS and SSH are not affected by this because those protocols break large
amounts of data into small chunks. Similarly, most applications will not
attempt to encrypt/decrypt 64GB of data in one chunk.
Overflow checking is not enabled in release mode by default, but
RUSTFLAGS="-C overflow-checks" or overflow-checks = true in the Cargo.toml
profile can override this. Overflow checking is usually enabled by default in
debug mode.
openssl: Use-After-Free in `Md::fetch` and `Cipher::fetch`
Previous versions of tracing-subscriber were vulnerable to ANSI escape sequence injection attacks. Untrusted user input containing ANSI escape sequences could be injected into terminal output when logged, potentially allowing attackers to:
Manipulate terminal title bars
Clear screens or modify terminal display
Potentially mislead users through terminal manipulation
In isolation, impact is minimal, however security issues have been found in terminal emulators that enabled an attacker to use ANSI escape sequences via logs to exploit vulnerabilities in the terminal emulator.
This was patched in PR #3368 to escape ANSI control characters from user input.
In the unique reclaim path of BytesMut::reserve, the condition
if v_capacity >= new_cap + offset
uses an unchecked addition. When new_cap + offset overflows usize in release builds, this condition may incorrectly pass, causing self.cap to be set to a value that exceeds the actual allocated capacity. Subsequent APIs such as spare_capacity_mut() then trust this corrupted cap value and may create out-of-bounds slices, leading to UB.
This behavior is observable in release builds (integer overflow wraps), whereas debug builds panic due to overflow checks.
PoC
use bytes::*;
fn main() {
let mut a = BytesMut::from(&b"hello world"[..]);
let mut b = a.split_off(5);
// Ensure b becomes the unique owner of the backing storage
drop(a);
// Trigger overflow in new_cap + offset inside reserve
b.reserve(usize::MAX - 6);
// This call relies on the corrupted cap and may cause UB & HBO
b.put_u8(b'h');
}
Workarounds
Users of BytesMut::reserve are only affected if integer overflow checks are configured to wrap. When integer overflow is configured to panic, this issue does not apply.
When user-provided input is provided to any type that parses with the RFC 2822 format, a denial of
service attack via stack exhaustion is possible. The attack relies on formally deprecated and
rarely-used features that are part of the RFC 2822 format used in a malicious manner. Ordinary,
non-malicious input will never encounter this scenario.
Patches
A limit to the depth of recursion was added in v0.3.47. From this version, an error will be returned
rather than exhausting the stack.
Workarounds
Limiting the length of user input is the simplest way to avoid stack exhaustion, as the amount of
the stack consumed would be at most a factor of the length of the input.
