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Fix possible runtime panic in Lgetxattr

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If `unix.Lgetxattr` returns an error, then `sz == -1` which will cause a
runtime panic if `errno == unix.ERANGE`.

Signed-off-by: Sascha Grunert <sgrunert@suse.com>
This commit is contained in:
Sascha Grunert 2019-12-04 14:25:58 +01:00
parent e25754b80c
commit 4138cd22ab
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GPG key ID: 8CE029DD1A866E52
1 changed files with 15 additions and 6 deletions
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21
pkg/system/xattrs_linux.go
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@ -6,19 +6,28 @@ import "golang.org/x/sys/unix"
// and associated with the given path in the file system.
// It will returns a nil slice and nil error if the xattr is not set.
func Lgetxattr(path string, attr string) ([]byte, error) {
// Start with a 128 length byte array
dest := make([]byte, 128)
sz, errno := unix.Lgetxattr(path, attr, dest)
if errno == unix.ENODATA {
switch {
case errno == unix.ENODATA:
return nil, nil
}
if errno == unix.ERANGE {
case errno == unix.ERANGE:
// 128 byte array might just not be good enough. A dummy buffer is used
// to get the real size of the xattrs on disk
sz, errno = unix.Lgetxattr(path, attr, []byte{})
if errno != nil {
return nil, errno
}
dest = make([]byte, sz)
sz, errno = unix.Lgetxattr(path, attr, dest)
}
if errno != nil {
if errno != nil {
return nil, errno
}
case errno != nil:
return nil, errno
}
return dest[:sz], nil
}