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| author | Russ Cox <rsc@golang.org> | 2021-12-08 18:05:11 -0500 |
|---|---|---|
| committer | Filippo Valsorda <filippo@golang.org> | 2021-12-09 12:28:55 +0000 |
| commit | 44a3fb49d99cc8a4de4925b69650f97bb07faf1d (patch) | |
| tree | 51c33fb654e88ceb47477a8d085d65b5622ba065 | |
| parent | caced3b213e879b2af0508f5f6a2d3bb3d6ef2a9 (diff) | |
| download | go-44a3fb49d99cc8a4de4925b69650f97bb07faf1d.tar.gz go-44a3fb49d99cc8a4de4925b69650f97bb07faf1d.zip | |
[release-branch.go1.16] syscall: fix ForkLock spurious close(0) on pipe failure
Pipe (and therefore forkLockPipe) does not make any guarantees
about the state of p after a failed Pipe(p). Avoid that assumption
and the too-clever goto, so that we don't accidentally Close a real fd
if the failed pipe leaves p[0] or p[1] set >= 0.
Updates #50057
Fixes CVE-2021-44717
Change-Id: Iff8e19a6efbba0c73cc8b13ecfae381c87600bb4
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1291270
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/370514
Trust: Filippo Valsorda <filippo@golang.org>
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Alex Rakoczy <alex@golang.org>
| -rw-r--r-- | src/syscall/exec_unix.go | 20 |
1 files changed, 6 insertions, 14 deletions
diff --git a/src/syscall/exec_unix.go b/src/syscall/exec_unix.go index 1f49c78ef9d..290dd383ecb 100644 --- a/src/syscall/exec_unix.go +++ b/src/syscall/exec_unix.go @@ -152,9 +152,6 @@ func forkExec(argv0 string, argv []string, attr *ProcAttr) (pid int, err error) sys = &zeroSysProcAttr } - p[0] = -1 - p[1] = -1 - // Convert args to C form. argv0p, err := BytePtrFromString(argv0) if err != nil { @@ -204,14 +201,17 @@ func forkExec(argv0 string, argv []string, attr *ProcAttr) (pid int, err error) // Allocate child status pipe close on exec. if err = forkExecPipe(p[:]); err != nil { - goto error + ForkLock.Unlock() + return 0, err } // Kick off child. pid, err1 = forkAndExecInChild(argv0p, argvp, envvp, chroot, dir, attr, sys, p[1]) if err1 != 0 { - err = Errno(err1) - goto error + Close(p[0]) + Close(p[1]) + ForkLock.Unlock() + return 0, Errno(err1) } ForkLock.Unlock() @@ -243,14 +243,6 @@ func forkExec(argv0 string, argv []string, attr *ProcAttr) (pid int, err error) // Read got EOF, so pipe closed on exec, so exec succeeded. return pid, nil - -error: - if p[0] >= 0 { - Close(p[0]) - Close(p[1]) - } - ForkLock.Unlock() - return 0, err } // Combination of fork and exec, careful to be thread safe. |