diff options
| author | Eric W. Biederman <ebiederm@xmission.com> | 2020-11-20 17:14:19 -0600 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2020-12-10 12:39:32 -0600 |
| commit | 1f702603e7125a390b5cdf5ce00539781cfcc86a (patch) | |
| tree | ed62c7824115f6c452bf18f24b2f401b6206e020 | |
| parent | b6043501289ebf169ae19b810a882d517377302f (diff) | |
exec: Simplify unshare_files
Now that exec no longer needs to return the unshared files to their
previous value there is no reason to return displaced.
Instead when unshare_fd creates a copy of the file table, call
put_files_struct before returning from unshare_files.
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
v1: https://lkml.kernel.org/r/20200817220425.9389-2-ebiederm@xmission.com
Link: https://lkml.kernel.org/r/20201120231441.29911-2-ebiederm@xmission.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
| -rw-r--r-- | fs/coredump.c | 5 | ||||
| -rw-r--r-- | fs/exec.c | 5 | ||||
| -rw-r--r-- | include/linux/fdtable.h | 2 | ||||
| -rw-r--r-- | kernel/fork.c | 12 |
4 files changed, 9 insertions, 15 deletions
diff --git a/fs/coredump.c b/fs/coredump.c index 0cd9056d79cc..abf807235262 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -585,7 +585,6 @@ void do_coredump(const kernel_siginfo_t *siginfo) int ispipe; size_t *argv = NULL; int argc = 0; - struct files_struct *displaced; /* require nonrelative corefile path and be extra careful */ bool need_suid_safe = false; bool core_dumped = false; @@ -791,11 +790,9 @@ void do_coredump(const kernel_siginfo_t *siginfo) } /* get us an unshared descriptor table; almost always a no-op */ - retval = unshare_files(&displaced); + retval = unshare_files(); if (retval) goto close_fail; - if (displaced) - put_files_struct(displaced); if (!dump_interrupted()) { /* * umh disabled with CONFIG_STATIC_USERMODEHELPER_PATH="" would diff --git a/fs/exec.c b/fs/exec.c index 0d6533ab1c97..48fa4fc1b116 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1238,7 +1238,6 @@ void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec) int begin_new_exec(struct linux_binprm * bprm) { struct task_struct *me = current; - struct files_struct *displaced; int retval; /* Once we are committed compute the creds */ @@ -1259,11 +1258,9 @@ int begin_new_exec(struct linux_binprm * bprm) goto out; /* Ensure the files table is not shared. */ - retval = unshare_files(&displaced); + retval = unshare_files(); if (retval) goto out; - if (displaced) - put_files_struct(displaced); /* * Must be called _before_ exec_mmap() as bprm->mm is diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h index a32bf47c593e..f46a084b60b2 100644 --- a/include/linux/fdtable.h +++ b/include/linux/fdtable.h @@ -109,7 +109,7 @@ struct task_struct; struct files_struct *get_files_struct(struct task_struct *); void put_files_struct(struct files_struct *fs); void reset_files_struct(struct files_struct *); -int unshare_files(struct files_struct **); +int unshare_files(void); struct files_struct *dup_fd(struct files_struct *, unsigned, int *) __latent_entropy; void do_close_on_exec(struct files_struct *); int iterate_fd(struct files_struct *, unsigned, diff --git a/kernel/fork.c b/kernel/fork.c index 32083db7a2a2..837b546528c8 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -3023,21 +3023,21 @@ SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) * the exec layer of the kernel. */ -int unshare_files(struct files_struct **displaced) +int unshare_files(void) { struct task_struct *task = current; - struct files_struct *copy = NULL; + struct files_struct *old, *copy = NULL; int error; error = unshare_fd(CLONE_FILES, NR_OPEN_MAX, ©); - if (error || !copy) { - *displaced = NULL; + if (error || !copy) return error; - } - *displaced = task->files; + + old = task->files; task_lock(task); task->files = copy; task_unlock(task); + put_files_struct(old); return 0; } |