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| author |   Dmitry V. Levin <ldv@altlinux.org> | 2019-07-14 19:20:47 +0300 |
|---|---|---|
| committer |   Christian Brauner <christian@brauner.io> | 2019-07-14 20:36:12 +0200 |
| commit | 028b6e8a89de9133a869bb4cd1bc72445b1ec8ca (patch) | |
| tree | 1f7464eb4b1f64d20def0019a2818e8c3e9c2c74 /kernel | |
| parent | Merge tag 'dlm-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm (diff) | |
| download | linux-dev-028b6e8a89de9133a869bb4cd1bc72445b1ec8ca.tar.xz linux-dev-028b6e8a89de9133a869bb4cd1bc72445b1ec8ca.zip | |
clone: fix CLONE_PIDFD support
The introduction of clone3 syscall accidentally broke CLONE_PIDFD
support in traditional clone syscall on compat x86 and those
architectures that use do_fork to implement clone syscall.
This bug was found by strace test suite.
Link: https://strace.io/logs/strace/2019-07-12
Fixes: 7f192e3cd316 ("fork: add clone3")
Bisected-and-tested-by: Anatoly Pugachev <matorola@gmail.com>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Link: https://lore.kernel.org/r/20190714162047.GB10389@altlinux.org
Signed-off-by: Christian Brauner <christian@brauner.io>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/fork.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 8f3e2d97d771..ef1e05a68827 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2406,6 +2406,16 @@ long _do_fork(struct kernel_clone_args *args) return nr; } +bool legacy_clone_args_valid(const struct kernel_clone_args *kargs) +{ + /* clone(CLONE_PIDFD) uses parent_tidptr to return a pidfd */ + if ((kargs->flags & CLONE_PIDFD) && + (kargs->flags & CLONE_PARENT_SETTID)) + return false; + + return true; +} + #ifndef CONFIG_HAVE_COPY_THREAD_TLS /* For compatibility with architectures that call do_fork directly rather than * using the syscall entry points below. */ @@ -2417,6 +2427,7 @@ long do_fork(unsigned long clone_flags, { struct kernel_clone_args args = { .flags = (clone_flags & ~CSIGNAL), + .pidfd = parent_tidptr, .child_tid = child_tidptr, .parent_tid = parent_tidptr, .exit_signal = (clone_flags & CSIGNAL), @@ -2424,6 +2435,9 @@ long do_fork(unsigned long clone_flags, .stack_size = stack_size, }; + if (!legacy_clone_args_valid(&args)) + return -EINVAL; + return _do_fork(&args); } #endif @@ -2505,8 +2519,7 @@ SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, .tls = tls, }; - /* clone(CLONE_PIDFD) uses parent_tidptr to return a pidfd */ - if ((clone_flags & CLONE_PIDFD) && (clone_flags & CLONE_PARENT_SETTID)) + if (!legacy_clone_args_valid(&args)) return -EINVAL; return _do_fork(&args); |