diff options
Diffstat (limited to 'fs/exec.c')
| -rw-r--r-- | fs/exec.c | 44 |
1 files changed, 35 insertions, 9 deletions
diff --git a/fs/exec.c b/fs/exec.c index 9c349a74f385..d60794372963 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1246,13 +1246,12 @@ int begin_new_exec(struct linux_binprm * bprm) */ bprm->point_of_no_return = true; - /* - * Make this the only thread in the thread group. - */ + /* Make this the only thread in the thread group */ retval = de_thread(me); if (retval) goto out; - + /* see the comment in check_unsafe_exec() */ + current->fs->in_exec = 0; /* * Cancel any io_uring activity across execve */ @@ -1351,7 +1350,28 @@ int begin_new_exec(struct linux_binprm * bprm) set_dumpable(current->mm, SUID_DUMP_USER); perf_event_exec(); - __set_task_comm(me, kbasename(bprm->filename), true); + + /* + * If the original filename was empty, alloc_bprm() made up a path + * that will probably not be useful to admins running ps or similar. + * Let's fix it up to be something reasonable. + */ + if (bprm->comm_from_dentry) { + /* + * Hold RCU lock to keep the name from being freed behind our back. + * Use acquire semantics to make sure the terminating NUL from + * __d_alloc() is seen. + * + * Note, we're deliberately sloppy here. We don't need to care about + * detecting a concurrent rename and just want a terminated name. + */ + rcu_read_lock(); + __set_task_comm(me, smp_load_acquire(&bprm->file->f_path.dentry->d_name.name), + true); + rcu_read_unlock(); + } else { + __set_task_comm(me, kbasename(bprm->filename), true); + } /* An exec changes our domain. We are no longer part of the thread group */ @@ -1493,6 +1513,8 @@ static void free_bprm(struct linux_binprm *bprm) } free_arg_pages(bprm); if (bprm->cred) { + /* in case exec fails before de_thread() succeeds */ + current->fs->in_exec = 0; mutex_unlock(¤t->signal->cred_guard_mutex); abort_creds(bprm->cred); } @@ -1527,11 +1549,13 @@ static struct linux_binprm *alloc_bprm(int fd, struct filename *filename, int fl if (fd == AT_FDCWD || filename->name[0] == '/') { bprm->filename = filename->name; } else { - if (filename->name[0] == '\0') + if (filename->name[0] == '\0') { bprm->fdpath = kasprintf(GFP_KERNEL, "/dev/fd/%d", fd); - else + bprm->comm_from_dentry = 1; + } else { bprm->fdpath = kasprintf(GFP_KERNEL, "/dev/fd/%d/%s", fd, filename->name); + } if (!bprm->fdpath) goto out_free; @@ -1597,6 +1621,10 @@ static void check_unsafe_exec(struct linux_binprm *bprm) * suid exec because the differently privileged task * will be able to manipulate the current directory, etc. * It would be nice to force an unshare instead... + * + * Otherwise we set fs->in_exec = 1 to deny clone(CLONE_FS) + * from another sub-thread until de_thread() succeeds, this + * state is protected by cred_guard_mutex we hold. */ n_fs = 1; spin_lock(&p->fs->lock); @@ -1855,7 +1883,6 @@ static int bprm_execve(struct linux_binprm *bprm) sched_mm_cid_after_execve(current); /* execve succeeded */ - current->fs->in_exec = 0; current->in_execve = 0; rseq_execve(current); user_events_execve(current); @@ -1874,7 +1901,6 @@ out: force_fatal_sig(SIGSEGV); sched_mm_cid_after_execve(current); - current->fs->in_exec = 0; current->in_execve = 0; return retval; |