Commit be27cd64 authored by Kees Cook's avatar Kees Cook Committed by Theodore Ts'o
Browse files

ext4: use memtostr_pad() for s_volume_name 



As with the other strings in struct ext4_super_block, s_volume_name is
not NUL terminated. The other strings were marked in commit 072ebb3b
("ext4: add nonstring annotations to ext4.h"). Using strscpy() isn't
the right replacement for strncpy(); it should use memtostr_pad()
instead.

Reported-by: default avatar <syzbot+50835f73143cc2905b9e@syzkaller.appspotmail.com>
Closes: https://lore.kernel.org/all/00000000000019f4c00619192c05@google.com/


Fixes: 744a5638 ("ext4: replace deprecated strncpy with alternatives")
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Link: https://patch.msgid.link/20240523225408.work.904-kees@kernel.org


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 7c73ddb7

fs/ext4/ext4.h

+1 −1
Original line number Diff line number Diff line
@@ -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 */

	/*

fs/ext4/ioctl.c

+1 −1
Original line number Diff line number Diff line
@@ -1151,7 +1151,7 @@ static int ext4_ioctl_getlabel(struct ext4_sb_info *sbi, char __user *user_label 
	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)))