summaryrefslogtreecommitdiff
path: root/kernel/fork.c
diff options
context:
space:
mode:
authorDmitry V. Levin <ldv@altlinux.org>2019-07-14 19:20:47 +0300
committerChristian Brauner <christian@brauner.io>2019-07-14 20:36:12 +0200
commit028b6e8a89de9133a869bb4cd1bc72445b1ec8ca (patch)
tree1f7464eb4b1f64d20def0019a2818e8c3e9c2c74 /kernel/fork.c
parent964a4eacef67503a1154f7e0a75f52fbdce52022 (diff)
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/fork.c')
-rw-r--r--kernel/fork.c17
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);