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getrandom: allow GRND_INSECURE flag #13250

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copybara-service merged 1 commit into from
May 27, 2026
+4 −3
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getrandom: allow GRND_INSECURE flag #13250

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7 changes: 4 additions & 3 deletions pkg/sentry/syscalls/linux/sys_random.go
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Original file line number Diff line number Diff line change
Expand Up @@ -29,22 +29,23 @@ import (
const (
_GRND_NONBLOCK = 0x1
_GRND_RANDOM = 0x2
_GRND_INSECURE = 0x4
)

// GetRandom implements the linux syscall getrandom(2).
//
// In a multi-tenant/shared environment, the only valid implementation is to
// fetch data from the urandom pool, otherwise starvation attacks become
// possible. The urandom pool is also expected to have plenty of entropy, thus
// the GRND_RANDOM flag is ignored. The GRND_NONBLOCK flag does not apply, as
// the pool will already be initialized.
// the GRND_RANDOM and GRND_INSECURE flags are ignored. The GRND_NONBLOCK flag
// does not apply, as the pool will already be initialized.
func GetRandom(t *kernel.Task, sysno uintptr, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
addr := args[0].Pointer()
length := args[1].SizeT()
flags := args[2].Int()

// Flags are checked for validity but otherwise ignored. See above.
if flags & ^(_GRND_NONBLOCK|_GRND_RANDOM) != 0 {
if flags & ^(_GRND_NONBLOCK|_GRND_RANDOM|_GRND_INSECURE) != 0 {
return 0, nil, linuxerr.EINVAL
}

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