4.4-stable review patch. If anyone has any objections, please let me know.
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From: Theodore Ts'o tytso@mit.edu
commit 7d95178c77014dbd8dce36ee40bbbc5e6c121ff5 upstream.
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 wen.xu@gatech.edu Signed-off-by: Theodore Ts'o tytso@mit.edu Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/ext4/xattr.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -197,6 +197,8 @@ ext4_xattr_check_names(struct ext4_xattr 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; }