From 7d95178c77014dbd8dce36ee40bbbc5e6c121ff5 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Wed, 1 Aug 2018 12:36:52 -0400 Subject: [PATCH] ext4: check for NUL characters in extended attribute's name Extended attribute names are defined to be NUL-terminated, so the name must not contain a NUL character. This is important because there are places when remove extended attribute, the code uses strlen to determine the length of the entry. That should probably be fixed at some point, but code is currently really messy, so the simplest fix for now is to simply validate that the extended attributes are sane. https://bugzilla.kernel.org/show_bug.cgi?id=200401 Reported-by: Wen Xu Signed-off-by: Theodore Ts'o Cc: stable@vger.kernel.org --- fs/ext4/xattr.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index 723df14f4084..f36fc5d5b257 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -190,6 +190,8 @@ ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end, struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e); if ((void *)next >= end) return -EFSCORRUPTED; + if (strnlen(e->e_name, e->e_name_len) != e->e_name_len) + return -EFSCORRUPTED; e = next; }