[PATCH 14/14] getcwd(2): clean up error handling
From: Al Viro <viro@zeniv.linux.org.uk>
Date: 2021-05-19 00:51:13
Also in:
linux-fsdevel, linux-s390, lkml
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> --- fs/d_path.c | 29 ++++++++++++----------------- 1 file changed, 12 insertions(+), 17 deletions(-)
diff --git a/fs/d_path.c b/fs/d_path.c
index 8a9cd44f6689..23a53f7b5c71 100644
--- a/fs/d_path.c
+++ b/fs/d_path.c@@ -390,9 +390,11 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) rcu_read_lock(); get_fs_root_and_pwd_rcu(current->fs, &root, &pwd); - error = -ENOENT; - if (!d_unlinked(pwd.dentry)) { - unsigned long len; + if (unlikely(d_unlinked(pwd.dentry))) { + rcu_read_unlock(); + error = -ENOENT; + } else { + unsigned len; DECLARE_BUFFER(b, page, PATH_MAX); prepend(&b, "", 1);
@@ -400,23 +402,16 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) prepend(&b, "(unreachable)", 13); rcu_read_unlock(); - if (b.len < 0) { - error = -ENAMETOOLONG; - goto out; - } - - error = -ERANGE; len = PATH_MAX - b.len; - if (len <= size) { + if (unlikely(len > PATH_MAX)) + error = -ENAMETOOLONG; + else if (unlikely(len > size)) + error = -ERANGE; + else if (copy_to_user(buf, b.buf, len)) + error = -EFAULT; + else error = len; - if (copy_to_user(buf, b.buf, len)) - error = -EFAULT; - } - } else { - rcu_read_unlock(); } - -out: __putname(page); return error; }
--
2.11.0