diff --git a/fs/exec.c b/fs/exec.c index fb8813cc532d..42952cf90f4a 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1245,6 +1245,7 @@ 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 */ @@ -1264,6 +1265,13 @@ int begin_new_exec(struct linux_binprm * bprm) if (retval) goto out; + /* Ensure the files table is not shared. */ + retval = unshare_files(&displaced); + if (retval) + goto out; + if (displaced) + put_files_struct(displaced); + /* * Must be called _before_ exec_mmap() as bprm->mm is * not visibile until then. This also enables the update @@ -1789,7 +1797,6 @@ static int bprm_execve(struct linux_binprm *bprm, int fd, struct filename *filename, int flags) { struct file *file; - struct files_struct *displaced; int retval; /* @@ -1797,13 +1804,9 @@ static int bprm_execve(struct linux_binprm *bprm, */ io_uring_task_cancel(); - retval = unshare_files(&displaced); - if (retval) - return retval; - retval = prepare_bprm_creds(bprm); if (retval) - goto out_files; + return retval; check_unsafe_exec(bprm); current->in_execve = 1; @@ -1818,8 +1821,12 @@ static int bprm_execve(struct linux_binprm *bprm, bprm->file = file; /* * Record that a name derived from an O_CLOEXEC fd will be - * inaccessible after exec. Relies on having exclusive access to - * current->files (due to unshare_files above). + * inaccessible after exec. This allows the code in exec to + * choose to fail when the executable is not mmaped into the + * interpreter and an open file descriptor is not passed to + * the interpreter. This makes for a better user experience + * than having the interpreter start and then immediately fail + * when it finds the executable is inaccessible. */ if (bprm->fdpath && get_close_on_exec(fd)) bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE; @@ -1839,8 +1846,6 @@ static int bprm_execve(struct linux_binprm *bprm, rseq_execve(current); acct_update_integrals(current); task_numa_free(current, false); - if (displaced) - put_files_struct(displaced); return retval; out: @@ -1857,10 +1862,6 @@ out_unmark: current->fs->in_exec = 0; current->in_execve = 0; -out_files: - if (displaced) - reset_files_struct(displaced); - return retval; }