linux-kernel - [PATCH 5.8 26/70] efivarfs: Replace invalid slashes with exclamation marks in dentries.

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Date:   Sat, 31 Oct 2020 12:35:58 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Michael Schaller <misch@...gle.com>,
        Ard Biesheuvel <ardb@...nel.org>,
        dann frazier <dann.frazier@...onical.com>
Subject: [PATCH 5.8 26/70] efivarfs: Replace invalid slashes with exclamation marks in dentries.

From: Michael Schaller <misch@...gle.com>

commit 336af6a4686d885a067ecea8c3c3dd129ba4fc75 upstream.

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/.

Signed-off-by: Michael Schaller <misch@...gle.com>
Link: https://lore.kernel.org/r/20200925074502.150448-1-misch@google.com
Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
Signed-off-by: dann frazier <dann.frazier@...onical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/efivarfs/super.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -141,6 +141,9 @@ static int efivarfs_callback(efi_char16_
 
 	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)