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Code Issues

implement util error

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Signed-off-by: yihuaf <yihuaf@unkies.org>
This commit is contained in:
yihuaf 2023-05-06 04:26:08 +00:00
parent 9968af0f84
commit fb4facacb0
1 changed files with 180 additions and 57 deletions
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237
crates/libcontainer/src/utils.rs
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@ -1,7 +1,5 @@
//! Utility functionality
use anyhow::Context;
use anyhow::{bail, Result};
use nix::sys::stat::Mode;
use nix::sys::statfs;
use nix::unistd;
@ -15,24 +13,45 @@ use std::os::unix::fs::DirBuilderExt;
use std::os::unix::prelude::{AsRawFd, OsStrExt};
use std::path::{Component, Path, PathBuf};
#[derive(Debug, thiserror::Error)]
pub enum PathBufExtError {
#[error("relative path cannot be converted to the path in the container")]
RelativePath,
#[error("failed to strip prefix from {path:?}")]
StripPrefix {
path: PathBuf,
source: std::path::StripPrefixError,
},
#[error("failed to canonicalize path {path:?}")]
Canonicalize {
path: PathBuf,
source: std::io::Error,
},
#[error("failed to get current directory")]
CurrentDir { source: std::io::Error },
}
pub trait PathBufExt {
fn as_relative(&self) -> Result<&Path>;
fn join_safely<P: AsRef<Path>>(&self, p: P) -> Result<PathBuf>;
fn canonicalize_safely(&self) -> Result<PathBuf>;
fn as_relative(&self) -> Result<&Path, PathBufExtError>;
fn join_safely<P: AsRef<Path>>(&self, p: P) -> Result<PathBuf, PathBufExtError>;
fn canonicalize_safely(&self) -> Result<PathBuf, PathBufExtError>;
fn normalize(&self) -> PathBuf;
}
impl PathBufExt for Path {
fn as_relative(&self) -> Result<&Path> {
if self.is_relative() {
bail!("relative path cannot be converted to the path in the container.")
} else {
self.strip_prefix("/")
.with_context(|| format!("failed to strip prefix from {self:?}"))
fn as_relative(&self) -> Result<&Path, PathBufExtError> {
match self.is_relative() {
true => Err(PathBufExtError::RelativePath),
false => Ok(self
.strip_prefix("/")
.map_err(|e| PathBufExtError::StripPrefix {
path: self.to_path_buf(),
source: e,
})?),
}
}
fn join_safely<P: AsRef<Path>>(&self, path: P) -> Result<PathBuf> {
fn join_safely<P: AsRef<Path>>(&self, path: P) -> Result<PathBuf, PathBufExtError> {
let path = path.as_ref();
if path.is_relative() {
return Ok(self.join(path));
@ -40,19 +59,25 @@ impl PathBufExt for Path {
let stripped = path
.strip_prefix("/")
.with_context(|| format!("failed to strip prefix from {}", path.display()))?;
.map_err(|e| PathBufExtError::StripPrefix {
path: self.to_path_buf(),
source: e,
})?;
Ok(self.join(stripped))
}
/// Canonicalizes existing and not existing paths
fn canonicalize_safely(&self) -> Result<PathBuf> {
fn canonicalize_safely(&self) -> Result<PathBuf, PathBufExtError> {
if self.exists() {
self.canonicalize()
.with_context(|| format!("failed to canonicalize path {self:?}"))
.map_err(|e| PathBufExtError::Canonicalize {
path: self.to_path_buf(),
source: e,
})
} else {
if self.is_relative() {
let p = std::env::current_dir()
.context("could not get current directory")?
.map_err(|e| PathBufExtError::CurrentDir { source: e })?
.join(self);
return Ok(p.normalize());
}
@ -120,14 +145,30 @@ pub fn get_user_home(uid: u32) -> Option<PathBuf> {
}
}
pub fn do_exec(path: impl AsRef<Path>, args: &[String]) -> Result<()> {
let p = CString::new(path.as_ref().as_os_str().as_bytes())
.with_context(|| format!("failed to convert path {:?} to cstring", path.as_ref()))?;
let a: Vec<CString> = args
#[derive(Debug, thiserror::Error)]
pub enum DoExecError {
#[error("failed to convert path to cstring")]
PathToCString {
source: std::ffi::NulError,
path: PathBuf,
},
#[error("failed to execvp")]
Execvp { source: nix::Error },
}
pub fn do_exec(path: impl AsRef<Path>, args: &[String]) -> Result<(), DoExecError> {
let p = CString::new(path.as_ref().as_os_str().as_bytes()).map_err(|e| {
DoExecError::PathToCString {
source: e,
path: path.as_ref().to_path_buf(),
}
})?;
let cArgs: Vec<CString> = args
.iter()
.map(|s| CString::new(s.as_bytes()).unwrap_or_default())
.collect();
unistd::execvp(&p, &a)?;
unistd::execvp(&p, &cArgs).map_err(|err| DoExecError::Execvp { source: err })?;
Ok(())
}
@ -146,20 +187,56 @@ pub fn get_cgroup_path(
}
}
pub fn write_file<P: AsRef<Path>, C: AsRef<[u8]>>(path: P, contents: C) -> Result<()> {
let path = path.as_ref();
fs::write(path, contents).with_context(|| format!("failed to write to {path:?}"))?;
Ok(())
#[derive(Debug, thiserror::Error)]
pub enum WrappedIOError {
#[error("failed to read from {path:?}")]
ReadFile {
source: std::io::Error,
path: PathBuf,
},
#[error("failed to write to {path:?}")]
WriteFile {
source: std::io::Error,
path: PathBuf,
},
#[error("failed to open {path:?}")]
Open {
source: std::io::Error,
path: PathBuf,
},
#[error("failed to create directory {path:?}")]
CreateDirAll {
source: std::io::Error,
path: PathBuf,
},
#[error("failed to get metadata")]
GetMetadata { source: std::io::Error },
#[error("metada doesn't match the expected attributes")]
MetadataMismatch,
}
pub fn create_dir_all<P: AsRef<Path>>(path: P) -> Result<()> {
let path = path.as_ref();
fs::create_dir_all(path).with_context(|| format!("failed to create directory {path:?}"))
pub fn write_file<P: AsRef<Path>, C: AsRef<[u8]>>(
path: P,
contents: C,
) -> Result<(), WrappedIOError> {
fs::write(path.as_ref(), contents).map_err(|err| WrappedIOError::WriteFile {
source: err,
path: path.as_ref().to_path_buf(),
})
}
pub fn open<P: AsRef<Path>>(path: P) -> Result<File> {
let path = path.as_ref();
File::open(path).with_context(|| format!("failed to open {path:?}"))
pub fn create_dir_all<P: AsRef<Path>>(path: P) -> Result<(), WrappedIOError> {
fs::create_dir_all(path.as_ref()).map_err(|err| WrappedIOError::CreateDirAll {
source: err,
path: path.as_ref().to_path_buf(),
})
}
pub fn open<P: AsRef<Path>>(path: P) -> Result<File, WrappedIOError> {
File::open(path.as_ref()).map_err(|err| WrappedIOError::Open {
source: err,
path: path.as_ref().to_path_buf(),
})
}
/// Creates the specified directory and all parent directories with the specified mode. Ensures
@ -175,19 +252,26 @@ pub fn open<P: AsRef<Path>>(path: P) -> Result<File> {
/// create_dir_all_with_mode(&path, 1000, Mode::S_IRWXU).unwrap();
/// assert!(path.exists())
/// ```
pub fn create_dir_all_with_mode<P: AsRef<Path>>(path: P, owner: u32, mode: Mode) -> Result<()> {
pub fn create_dir_all_with_mode<P: AsRef<Path>>(
path: P,
owner: u32,
mode: Mode,
) -> Result<(), WrappedIOError> {
let path = path.as_ref();
if !path.exists() {
DirBuilder::new()
.recursive(true)
.mode(mode.bits())
.create(path)
.with_context(|| format!("failed to create directory {}", path.display()))?;
.map_err(|err| WrappedIOError::CreateDirAll {
source: err,
path: path.to_path_buf(),
})?;
}
let metadata = path
.metadata()
.with_context(|| format!("failed to get metadata for {}", path.display()))?;
.map_err(|err| WrappedIOError::GetMetadata { source: err })?;
if metadata.is_dir()
&& metadata.st_uid() == owner
@ -195,27 +279,65 @@ pub fn create_dir_all_with_mode<P: AsRef<Path>>(path: P, owner: u32, mode: Mode)
{
Ok(())
} else {
bail!(
"metadata for {} does not possess the expected attributes",
path.display()
);
Err(WrappedIOError::MetadataMismatch)
}
}
#[derive(Debug, thiserror::Error)]
pub enum EnsureProcfsError {
#[error("failed to open {path:?}")]
OpenProcfs {
source: std::io::Error,
path: PathBuf,
},
#[error("failed to get statfs for {path:?}")]
StatfsProcfs { source: nix::Error, path: PathBuf },
#[error("{path:?} is not on the procfs")]
NotProcfs { path: PathBuf },
}
// Make sure a given path is on procfs. This is to avoid the security risk that
// /proc path is mounted over. Ref: CVE-2019-16884
pub fn ensure_procfs(path: &Path) -> Result<()> {
let procfs_fd = fs::File::open(path)?;
let fstat_info = statfs::fstatfs(&procfs_fd.as_raw_fd())?;
pub fn ensure_procfs(path: &Path) -> Result<(), EnsureProcfsError> {
let procfs_fd = fs::File::open(path).map_err(|err| EnsureProcfsError::OpenProcfs {
source: err,
path: path.to_path_buf(),
})?;
let fstat_info =
statfs::fstatfs(&procfs_fd.as_raw_fd()).map_err(|err| EnsureProcfsError::StatfsProcfs {
source: err,
path: path.to_path_buf(),
})?;
if fstat_info.filesystem_type() != statfs::PROC_SUPER_MAGIC {
bail!(format!("{path:?} is not on the procfs"));
return Err(EnsureProcfsError::NotProcfs {
path: path.to_path_buf(),
});
}
Ok(())
}
pub fn secure_join<P: Into<PathBuf>>(rootfs: P, unsafe_path: P) -> Result<PathBuf> {
#[derive(Debug, thiserror::Error)]
pub enum SecureJoinError {
#[error("dereference too many symlinks, may be infinite loop")]
TooManySymlinks,
#[error("unable to obtain symlink metadata")]
SymlinkMetadata {
source: std::io::Error,
path: PathBuf,
},
#[error("failed to read link")]
ReadLink {
source: std::io::Error,
path: PathBuf,
},
}
pub fn secure_join<P: Into<PathBuf>>(
rootfs: P,
unsafe_path: P,
) -> Result<PathBuf, SecureJoinError> {
let mut rootfs = rootfs.into();
let mut path = unsafe_path.into();
let mut clean_path = PathBuf::new();
@ -225,7 +347,7 @@ pub fn secure_join<P: Into<PathBuf>>(rootfs: P, unsafe_path: P) -> Result<PathBu
loop {
if i > 255 {
bail!("dereference too many symlinks, may be infinite loop");
return Err(SecureJoinError::TooManySymlinks);
}
let part_path = match part.next() {
@ -241,22 +363,22 @@ pub fn secure_join<P: Into<PathBuf>>(rootfs: P, unsafe_path: P) -> Result<PathBu
let curr_path = PathBuf::from(&rootfs).join(&clean_path).join(&part_path);
let metadata = match curr_path.symlink_metadata() {
Ok(metadata) => Some(metadata),
Err(error) => match error.kind() {
// if file does not exists, treat it as normal path
ErrorKind::NotFound => None,
other_error => {
bail!(
"unable to obtain symlink metadata for file {:?}: {:?}",
curr_path,
other_error
);
}
},
Err(err) if err.kind() == ErrorKind::NotFound => None,
Err(err) => {
return Err(SecureJoinError::SymlinkMetadata {
source: err,
path: curr_path,
})
}
};
if let Some(metadata) = metadata {
if metadata.file_type().is_symlink() {
let link_path = fs::read_link(curr_path)?;
let link_path =
fs::read_link(curr_path).map_err(|err| SecureJoinError::ReadLink {
source: err,
path: curr_path,
})?;
path = link_path.join(part.as_path());
part = path.iter();
@ -290,7 +412,7 @@ pub fn get_executable_path(name: &str, path_var: &str) -> Option<PathBuf> {
None
}
pub fn is_executable(path: &Path) -> Result<bool> {
pub fn is_executable(path: &Path) -> Result<bool, std::io::Error> {
use std::os::unix::fs::PermissionsExt;
let metadata = path.metadata()?;
let permissions = metadata.permissions();
@ -356,6 +478,7 @@ pub(crate) mod test_utils {
#[cfg(test)]
mod tests {
use super::*;
use anyhow::Result;
#[test]
pub fn test_get_unix_user() {