fortify/ldd/ldd.go
Ophestra Umiker 6232291cae
ldd: implement strict ldd output parser
Fortify needs to internally resolve helper program sandbox config. They are considered trusted and runs under the privileged UID so ldd output is used to determine libraries they need inside the sandbox environment.

Signed-off-by: Ophestra Umiker <cat@ophivana.moe>
2024-10-09 20:39:27 +09:00

85 lines
1.7 KiB
Go

package ldd
import (
"errors"
"fmt"
"math"
"os"
"os/exec"
"path"
"strconv"
"strings"
)
var (
ErrUnexpectedSeparator = errors.New("unexpected separator")
ErrPathNotAbsolute = errors.New("path not absolute")
ErrBadLocationFormat = errors.New("bad location format")
)
type Entry struct {
Name string `json:"name,omitempty"`
Path string `json:"path,omitempty"`
Location uint64 `json:"location"`
}
func Exec(p string) ([]*Entry, error) {
t := exec.Command("ldd", p)
t.Stdout = new(strings.Builder)
t.Stderr = os.Stderr
if err := t.Run(); err != nil {
return nil, err
}
out := t.Stdout.(fmt.Stringer).String()
payload := strings.Split(out, "\n")
result := make([]*Entry, len(payload))
for i, ent := range payload {
if len(ent) == 0 {
continue
}
segment := strings.SplitN(ent, " ", 5)
var iL int
switch len(segment) {
case 2: // /lib/ld-musl-x86_64.so.1 (0x7f04d14ef000)
iL = 1
result[i] = &Entry{Name: segment[0]}
case 4: // libc.musl-x86_64.so.1 => /lib/ld-musl-x86_64.so.1 (0x7f04d14ef000)
iL = 3
if segment[1] != "=>" {
return nil, ErrUnexpectedSeparator
}
if !path.IsAbs(segment[2]) {
return nil, ErrPathNotAbsolute
}
result[i] = &Entry{
Name: segment[0],
Path: segment[2],
}
default:
return nil, &EntryUnexpectedSegmentsError{ent}
}
if loc, err := parseLocation(segment[iL]); err != nil {
return nil, err
} else {
result[i].Location = loc
}
}
return result, nil
}
func parseLocation(s string) (uint64, error) {
if len(s) < 4 || s[len(s)-1] != ')' || s[:3] != "(0x" {
return math.MaxUint64, ErrBadLocationFormat
}
return strconv.ParseUint(s[3:len(s)-1], 16, 64)
}