On 2020/6/2 4:08, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@xxxxxxxxxx>
>
> If the dentry name passed to ->d_compare() fits in dentry::d_iname, then
> it may be concurrently modified by a rename. This can cause undefined
> behavior (possibly out-of-bounds memory accesses or crashes) in
> utf8_strncasecmp(), since fs/unicode/ isn't written to handle strings
> that may be concurrently modified.
>
> Fix this by first copying the filename to a stack buffer if needed.
> This way we get a stable snapshot of the filename.
>
> Fixes: 2c2eb7a300cd ("f2fs: Support case-insensitive file name lookups")
> Cc: <stable@xxxxxxxxxxxxxxx> # v5.4+
> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> Cc: Daniel Rosenberg <drosen@xxxxxxxxxx>
> Cc: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxxxx>
> Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx>
Thanks,
