vfs: Replace all non-returning strlcpy with strscpy

strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
No return values were used, so direct replacement is safe.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Message-Id: <20230510221119.3508930-1-azeemshaikh38@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/char_dev.c b/fs/char_dev.c
index 13deb45f1ec6519b5760ff6263b68dd5b83f31bb..950b6919fb872c191c58164000ffee249bc8a1b5 100644 (file)
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -150,7 +150,7 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor,
        cd->major = major;
        cd->baseminor = baseminor;
        cd->minorct = minorct;
-       strlcpy(cd->name, name, sizeof(cd->name));
+       strscpy(cd->name, name, sizeof(cd->name));
 
        if (!prev) {
                cd->next = curr;

diff --git a/fs/super.c b/fs/super.c
index 34afe411cf2bc397bf509e55493bc350c0063f50..8d8d68799b34fa170d2e82daaf4d4c34e388c08a 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -595,7 +595,7 @@ retry:
        fc->s_fs_info = NULL;
        s->s_type = fc->fs_type;
        s->s_iflags |= fc->s_iflags;
-       strlcpy(s->s_id, s->s_type->name, sizeof(s->s_id));
+       strscpy(s->s_id, s->s_type->name, sizeof(s->s_id));
        list_add_tail(&s->s_list, &super_blocks);
        hlist_add_head(&s->s_instances, &s->s_type->fs_supers);
        spin_unlock(&sb_lock);
@@ -674,7 +674,7 @@ retry:
                return ERR_PTR(err);
        }
        s->s_type = type;
-       strlcpy(s->s_id, type->name, sizeof(s->s_id));
+       strscpy(s->s_id, type->name, sizeof(s->s_id));
        list_add_tail(&s->s_list, &super_blocks);
        hlist_add_head(&s->s_instances, &type->fs_supers);
        spin_unlock(&sb_lock);