linux-kernel - [PATCH] efivarfs: Replace invalid slashes with exclamation marks in dentries.

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Date:   Fri, 18 Sep 2020 13:24:59 +0200
From:   Michael Schaller <misch@...gle.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     michael@...aller.de, Michael Schaller <misch@...gle.com>,
        Matthew Garrett <matthew.garrett@...ula.com>,
        Jeremy Kerr <jk@...abs.org>, Ard Biesheuvel <ardb@...nel.org>,
        linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] efivarfs: Replace invalid slashes with exclamation marks in dentries.

Without this patch efivarfs_alloc_dentry creates dentries with slashes in
their name if the respective EFI variable has slashes in its name. This in
turn causes EIO on getdents64, which prevents a complete directory listing
of /sys/firmware/efi/efivars/.

This patch replaces the invalid shlashes with exclamation marks like
kobject_set_name_vargs does for /sys/firmware/efi/vars/ to have consistently
named dentries under /sys/firmware/efi/vars/ and /sys/firmware/efi/efivars/.
---
 fs/efivarfs/super.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index 28bb5689333a..15880a68faad 100644
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -141,6 +141,9 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
 
 	name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';
 
+	/* replace invalid slashes like kobject_set_name_vargs does for /sys/firmware/efi/vars. */
+	strreplace(name, '/', '!');
+
 	inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0,
 				   is_removable);
 	if (!inode)
-- 
2.28.0.681.g6f77f65b4e-goog