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Fix data race by acquiring lock before accessing fields of FileAsync.

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PiperOrigin-RevId: 538645255
This commit is contained in:
Nayana Bidari
2023-06-07 18:12:00 -07:00
committed by gVisor bot
parent 60e4fec168
commit 5fed8c81b8
1 changed files with 20 additions and 8 deletions
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pkg/sentry/kernel/fasync/fasync.go
+20 -8
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@@ -103,6 +103,23 @@ func (a *FileAsync) recipient() *kernel.Task {
return t
}
// getPermAndSignal checks the credentials and returns the result of the
// credentials check and signal.
//
//go:nosplit
func (a *FileAsync) getPermAndSignal(c *auth.Credentials) (int32, bool) {
a.mu.Lock()
defer a.mu.Unlock()
sig := int32(a.signal)
// Logic from sigio_perm in fs/fcntl.c.
permCheck := (a.requester.EffectiveKUID == 0 ||
a.requester.EffectiveKUID == c.SavedKUID ||
a.requester.EffectiveKUID == c.RealKUID ||
a.requester.RealKUID == c.SavedKUID ||
a.requester.RealKUID == c.RealKUID)
return sig, permCheck
}
// NotifyEvent implements waiter.EventListener.NotifyEvent.
func (a *FileAsync) NotifyEvent(mask waiter.EventMask) {
t := a.recipient()
@@ -110,12 +127,7 @@ func (a *FileAsync) NotifyEvent(mask waiter.EventMask) {
return
}
c := t.Credentials()
// Logic from sigio_perm in fs/fcntl.c.
permCheck := (a.requester.EffectiveKUID == 0 ||
a.requester.EffectiveKUID == c.SavedKUID ||
a.requester.EffectiveKUID == c.RealKUID ||
a.requester.RealKUID == c.SavedKUID ||
a.requester.RealKUID == c.RealKUID)
sig, permCheck := a.getPermAndSignal(c)
if !permCheck {
return
}
@@ -123,8 +135,8 @@ func (a *FileAsync) NotifyEvent(mask waiter.EventMask) {
Signo: int32(linux.SIGIO),
Code: linux.SI_KERNEL,
}
if a.signal != 0 {
signalInfo.Signo = int32(a.signal)
if sig != 0 {
signalInfo.Signo = sig
signalInfo.SetFD(uint32(a.fd))
var band int64
for m, bandCode := range bandTable {