From: Kees Cook <keescook@xxxxxxxxxxxx>
commit be27cd64461c45a6088a91a04eba5cd44e1767ef upstream.
As with the other strings in struct ext4_super_block, s_volume_name is
not NUL terminated. The other strings were marked in commit 072ebb3bffe6
("ext4: add nonstring annotations to ext4.h"). Using strscpy() isn't
the right replacement for strncpy(); it should use memtostr_pad()
instead.
Reported-by: syzbot+50835f73143cc2905b9e@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://lore.kernel.org/all/00000000000019f4c00619192c05@xxxxxxxxxx/
Fixes: 744a56389f73 ("ext4: replace deprecated strncpy with alternatives")
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Link: https://patch.msgid.link/20240523225408.work.904-kees@xxxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/ext4.h | 2 +-
fs/ext4/ioctl.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1347,7 +1347,7 @@ struct ext4_super_block {
/*60*/ __le32 s_feature_incompat; /* incompatible feature set */
__le32 s_feature_ro_compat; /* readonly-compatible feature set */
/*68*/ __u8 s_uuid[16]; /* 128-bit uuid for volume */
-/*78*/ char s_volume_name[EXT4_LABEL_MAX]; /* volume name */
+/*78*/ char s_volume_name[EXT4_LABEL_MAX] __nonstring; /* volume name */
/*88*/ char s_last_mounted[64] __nonstring; /* directory where last mounted */
/*C8*/ __le32 s_algorithm_usage_bitmap; /* For compression */
/*
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -1151,7 +1151,7 @@ static int ext4_ioctl_getlabel(struct ex
BUILD_BUG_ON(EXT4_LABEL_MAX >= FSLABEL_MAX);
lock_buffer(sbi->s_sbh);
- strscpy_pad(label, sbi->s_es->s_volume_name);
+ memtostr_pad(label, sbi->s_es->s_volume_name);
unlock_buffer(sbi->s_sbh);
if (copy_to_user(user_label, label, sizeof(label)))
Patches currently in stable-queue which might be from keescook@xxxxxxxxxxxx are
queue-6.10/ext4-use-memtostr_pad-for-s_volume_name.patch
