Date: Thu, 17 Aug 2023 13:49:10 GMT From: Dag-Erling =?utf-8?Q?Sm=C3=B8rgrav?= <des@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: a4aaee2120ce - main - forkpty: Avoid fd leak if fork() fails. Message-ID: <202308171349.37HDnAq7063884@gitrepo.freebsd.org>
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The branch main has been updated by des: URL: https://cgit.FreeBSD.org/src/commit/?id=a4aaee2120ce0a121f86e39e214c2fabe82f2762 commit a4aaee2120ce0a121f86e39e214c2fabe82f2762 Author: Dag-Erling Smørgrav <des@FreeBSD.org> AuthorDate: 2023-08-17 13:48:42 +0000 Commit: Dag-Erling Smørgrav <des@FreeBSD.org> CommitDate: 2023-08-17 13:48:42 +0000 forkpty: Avoid fd leak if fork() fails. MFC after: 1 week Sponsored by: Klara, Inc. Reviewed by: allanjude Differential Revision: https://reviews.freebsd.org/D41491 --- lib/libutil/pty.c | 1 + lib/libutil/tests/Makefile | 1 + lib/libutil/tests/forkpty_test.c | 58 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 60 insertions(+) diff --git a/lib/libutil/pty.c b/lib/libutil/pty.c index f52407608e9a..e5b42a666c7f 100644 --- a/lib/libutil/pty.c +++ b/lib/libutil/pty.c @@ -95,6 +95,7 @@ forkpty(int *amaster, char *name, struct termios *termp, struct winsize *winp) return (-1); switch (pid = fork()) { case -1: + (void)close(master); (void)close(slave); return (-1); case 0: diff --git a/lib/libutil/tests/Makefile b/lib/libutil/tests/Makefile index 0c67747aeb3f..d29045d78a10 100644 --- a/lib/libutil/tests/Makefile +++ b/lib/libutil/tests/Makefile @@ -7,6 +7,7 @@ TAP_TESTS_C+= trimdomain_test TAP_TESTS_C+= trimdomain-nodomain_test ATF_TESTS_C+= cpuset_test ATF_TESTS_C+= expand_number_test +ATF_TESTS_C+= forkpty_test WARNS?= 2 LIBADD+= util diff --git a/lib/libutil/tests/forkpty_test.c b/lib/libutil/tests/forkpty_test.c new file mode 100644 index 000000000000..3e54cf310150 --- /dev/null +++ b/lib/libutil/tests/forkpty_test.c @@ -0,0 +1,58 @@ +/*- + * Copyright (c) 2023 Klara, Inc. + * + * SPDX-License-Identifier: BSD-2-Clause + */ + +#include <sys/resource.h> +#include <sys/wait.h> + +#include <errno.h> +#include <libutil.h> +#include <unistd.h> + +#include <atf-c.h> + +ATF_TC(forkfail); +ATF_TC_HEAD(forkfail, tc) +{ + atf_tc_set_md_var(tc, "descr", "Check for fd leak when fork() fails"); + atf_tc_set_md_var(tc, "require.user", "unprivileged"); +} + +ATF_TC_BODY(forkfail, tc) +{ + struct rlimit orl, nrl; + pid_t pid; + int prevfd, fd, pty; + + /* set process limit to 1 so fork() will fail */ + ATF_REQUIRE_EQ(0, getrlimit(RLIMIT_NPROC, &orl)); + nrl = orl; + nrl.rlim_cur = 1; + ATF_REQUIRE_EQ(0, setrlimit(RLIMIT_NPROC, &nrl)); + /* check first free fd */ + ATF_REQUIRE((fd = dup(0)) > 0); + ATF_REQUIRE_EQ(0, close(fd)); + /* attempt forkpty() */ + pid = forkpty(&pty, NULL, NULL, NULL); + if (pid == 0) { + /* child - fork() unexpectedly succeeded */ + _exit(0); + } + ATF_CHECK_ERRNO(EAGAIN, pid < 0); + if (pid > 0) { + /* parent - fork() unexpectedly succeeded */ + (void)waitpid(pid, NULL, 0); + } + /* check that first free fd hasn't changed */ + prevfd = fd; + ATF_REQUIRE((fd = dup(0)) > 0); + ATF_CHECK_EQ(prevfd, fd); +} + +ATF_TP_ADD_TCS(tp) +{ + ATF_TP_ADD_TC(tp, forkfail); + return (atf_no_error()); +}
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