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device_manager: check return value of dup(2)

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That function call can return -1 when it fails. Wrapping -1 into File
causes the code to panic when the File is dropped.

Signed-off-by: Wei Liu <liuwe@microsoft.com>
This commit is contained in:
Wei Liu 2021-11-17 17:30:42 +00:00 committed by Rob Bradford
parent 84630aa0b5
commit 9b3cab8c72
1 changed files with 28 additions and 7 deletions
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35
vmm/src/device_manager.rs
View File

@ -457,6 +457,9 @@ pub enum DeviceManagerError {
/// Failed to update memory mappings for VFIO user device
UpdateMemoryForVfioUserPciDevice(VfioUserPciDeviceError),
/// Cannot duplicate file descriptor
DupFd(vmm_sys_util::errno::Error),
}
pub type DeviceManagerResult<T> = result::Result<T, DeviceManagerError>;
@ -1750,17 +1753,32 @@ impl DeviceManager {
}
}
ConsoleOutputMode::Tty => {
// Duplicating the file descriptors like this is needed as otherwise
// they will be closed on a reboot and the numbers reused
// SAFETY: FFI call to dup. Trivially safe.
let stdout = unsafe { libc::dup(libc::STDOUT_FILENO) };
if stdout == -1 {
return vmm_sys_util::errno::errno_result().map_err(DeviceManagerError::DupFd);
}
// SAFETY: stdout is valid and owned solely by us.
let stdout = unsafe { File::from_raw_fd(stdout) };
// If an interactive TTY then we can accept input
// SAFETY: FFI call. Trivially safe.
if unsafe { libc::isatty(libc::STDIN_FILENO) == 1 } {
Endpoint::FilePair(
// Duplicating the file descriptors like this is needed as otherwise
// they will be closed on a reboot and the numbers reused
unsafe { File::from_raw_fd(libc::dup(libc::STDOUT_FILENO)) },
unsafe { File::from_raw_fd(libc::dup(libc::STDIN_FILENO)) },
)
// SAFETY: FFI call to dup. Trivially safe.
let stdin = unsafe { libc::dup(libc::STDIN_FILENO) };
if stdin == -1 {
return vmm_sys_util::errno::errno_result()
.map_err(DeviceManagerError::DupFd);
}
// SAFETY: stdin is valid and owned solely by us.
let stdin = unsafe { File::from_raw_fd(stdin) };
Endpoint::FilePair(stdout, stdin)
} else {
Endpoint::File(unsafe { File::from_raw_fd(libc::dup(libc::STDOUT_FILENO)) })
Endpoint::File(stdout)
}
}
ConsoleOutputMode::Null => Endpoint::Null,
@ -2885,6 +2903,9 @@ impl DeviceManager {
// descriptor opened from DeviceFd, preventing from unexpected behavior
// where the VfioContainer would try to use a closed file descriptor.
let dup_device_fd = unsafe { libc::dup(passthrough_device.as_raw_fd()) };
if dup_device_fd == -1 {
return vmm_sys_util::errno::errno_result().map_err(DeviceManagerError::DupFd);
}
// SAFETY the raw fd conversion here is safe because:
// 1. When running on KVM or MSHV, passthrough_device wraps around DeviceFd.