diff options
| -rw-r--r-- | MAINTAINERS | 3 | ||||
| -rw-r--r-- | fs/exec.c | 39 | ||||
| -rw-r--r-- | include/linux/sched.h | 2 | ||||
| -rw-r--r-- | kernel/fork.c | 1 |
4 files changed, 34 insertions, 11 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 8d1052fa6a69..39219b144c23 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -7955,12 +7955,13 @@ L: rust-for-linux@vger.kernel.org S: Maintained F: rust/kernel/net/phy.rs -EXEC & BINFMT API +EXEC & BINFMT API, ELF R: Eric Biederman <ebiederm@xmission.com> R: Kees Cook <keescook@chromium.org> L: linux-mm@kvack.org S: Supported T: git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/execve +F: Documentation/userspace-api/ELF.rst F: fs/*binfmt_*.c F: fs/exec.c F: include/linux/binfmts.h diff --git a/fs/exec.c b/fs/exec.c index 1a097c1c2f77..af4fbb61cd53 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -904,6 +904,10 @@ EXPORT_SYMBOL(transfer_args_to_stack); #endif /* CONFIG_MMU */ +/* + * On success, caller must call do_close_execat() on the returned + * struct file to close it. + */ static struct file *do_open_execat(int fd, struct filename *name, int flags) { struct file *file; @@ -948,6 +952,17 @@ exit: return ERR_PTR(err); } +/** + * open_exec - Open a path name for execution + * + * @name: path name to open with the intent of executing it. + * + * Returns ERR_PTR on failure or allocated struct file on success. + * + * As this is a wrapper for the internal do_open_execat(), callers + * must call allow_write_access() before fput() on release. Also see + * do_close_execat(). + */ struct file *open_exec(const char *name) { struct filename *filename = getname_kernel(name); @@ -1409,6 +1424,9 @@ int begin_new_exec(struct linux_binprm * bprm) out_unlock: up_write(&me->signal->exec_update_lock); + if (!bprm->cred) + mutex_unlock(&me->signal->cred_guard_mutex); + out: return retval; } @@ -1484,6 +1502,15 @@ static int prepare_bprm_creds(struct linux_binprm *bprm) return -ENOMEM; } +/* Matches do_open_execat() */ +static void do_close_execat(struct file *file) +{ + if (!file) + return; + allow_write_access(file); + fput(file); +} + static void free_bprm(struct linux_binprm *bprm) { if (bprm->mm) { @@ -1495,10 +1522,7 @@ static void free_bprm(struct linux_binprm *bprm) mutex_unlock(¤t->signal->cred_guard_mutex); abort_creds(bprm->cred); } - if (bprm->file) { - allow_write_access(bprm->file); - fput(bprm->file); - } + do_close_execat(bprm->file); if (bprm->executable) fput(bprm->executable); /* If a binfmt changed the interp, free it. */ @@ -1520,8 +1544,7 @@ static struct linux_binprm *alloc_bprm(int fd, struct filename *filename, int fl bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); if (!bprm) { - allow_write_access(file); - fput(file); + do_close_execat(file); return ERR_PTR(-ENOMEM); } @@ -1610,6 +1633,7 @@ static void check_unsafe_exec(struct linux_binprm *bprm) } rcu_read_unlock(); + /* "users" and "in_exec" locked for copy_fs() */ if (p->fs->users > n_fs) bprm->unsafe |= LSM_UNSAFE_SHARE; else @@ -1826,9 +1850,6 @@ static int exec_binprm(struct linux_binprm *bprm) return 0; } -/* - * sys_execve() executes a new program. - */ static int bprm_execve(struct linux_binprm *bprm) { int retval; diff --git a/include/linux/sched.h b/include/linux/sched.h index cdb8ea53c365..ffe8f618ab86 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -920,7 +920,7 @@ struct task_struct { unsigned sched_rt_mutex:1; #endif - /* Bit to tell LSMs we're in execve(): */ + /* Bit to tell TOMOYO we're in execve(): */ unsigned in_execve:1; unsigned in_iowait:1; #ifndef TIF_RESTORE_SIGMASK diff --git a/kernel/fork.c b/kernel/fork.c index 47ff3b35352e..0d944e92a43f 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1748,6 +1748,7 @@ static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) if (clone_flags & CLONE_FS) { /* tsk->fs is already what we want */ spin_lock(&fs->lock); + /* "users" and "in_exec" locked for check_unsafe_exec() */ if (fs->in_exec) { spin_unlock(&fs->lock); return -EAGAIN; |