Author: kevans
Date: Mon Apr 13 17:55:31 2020
New Revision: 359891
URL: https://svnweb.freebsd.org/changeset/base/359891
Log:
close_range/closefrom: fix regression from close_range introduction
close_range will clamp the range between [0, fdp->fd_lastfile], but failed
to take into account that fdp->fd_lastfile can become -1 if all fds are
closed. =-( In this scenario, just return because there's nothing further we
can do at the moment.
Add a test case for this, fork() and simply closefrom(0) twice in the child;
on the second invocation, fdp->fd_lastfile == -1 and will trigger a panic
before this change.
X-MFC-With: r359836
Modified:
head/sys/kern/kern_descrip.c
head/tests/sys/file/closefrom_test.c
Modified: head/sys/kern/kern_descrip.c
==============================================================================
--- head/sys/kern/kern_descrip.c Mon Apr 13 16:34:21 2020
(r359890)
+++ head/sys/kern/kern_descrip.c Mon Apr 13 17:55:31 2020
(r359891)
@@ -1333,6 +1333,14 @@ kern_close_range(struct thread *td, u_int lowfd, u_int
ret = EINVAL;
goto out;
}
+
+ /*
+ * If fdp->fd_lastfile == -1, we're dealing with either a fresh file
+ * table or one in which every fd has been closed. Just return
+ * successful; there's nothing left to do.
+ */
+ if (fdp->fd_lastfile == -1)
+ goto out;
/* Clamped to [lowfd, fd_lastfile] */
highfd = MIN(highfd, fdp->fd_lastfile);
for (fd = lowfd; fd <= highfd; fd++) {
Modified: head/tests/sys/file/closefrom_test.c
==============================================================================
--- head/tests/sys/file/closefrom_test.c Mon Apr 13 16:34:21 2020
(r359890)
+++ head/tests/sys/file/closefrom_test.c Mon Apr 13 17:55:31 2020
(r359891)
@@ -146,7 +146,7 @@ main(void)
pid_t pid;
int fd, i, start;
- printf("1..19\n");
+ printf("1..20\n");
/* We better start up with fd's 0, 1, and 2 open. */
start = devnull();
@@ -308,6 +308,22 @@ main(void)
if (fd != 3)
fail("close_range", "highest fd %d", fd);
ok("close_range");
+
+ /* Fork a child process to test closefrom(0) twice. */
+ pid = fork();
+ if (pid < 0)
+ fail_err("fork");
+ if (pid == 0) {
+ /* Child. */
+ closefrom(0);
+ closefrom(0);
+ cok(info, "closefrom(0)");
+ }
+ if (wait(NULL) < 0)
+ fail_err("wait");
+ if (info->failed)
+ fail(info->tag, "%s", info->message);
+ ok(info->tag);
return (0);
}
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