On 1 April 2015 at 05:41, Thomas Hebb <tommyhebb@xxxxxxxxx> wrote:
> By the time we reach strcmp_xattr_finder_info(), hfsplus_osx_getxattr()
> has already prefixed the user-provided xattr name with "osx.", so the
> existing check for the special FinderInfo attribute will always fail,
> and ENODATA will be returned to userspace.
>
> Since hfsplus_listxattr() reports the FinderInfo attribute, this
> behavior causes certain userspace utilities (e.g. patch) to fail, since
> the kernel lists an attribute that doesn't exist.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Hin-Tak Leung <htl10@xxxxxxxxxxxxxxxxxxxxx>
> Cc: Sergei Antonov <saproj@xxxxxxxxx>
> Cc: Anton Altaparmakov <anton@xxxxxxxxxx>
> Cc: Fabian Frederick <fabf@xxxxxxxxx>
> Cc: Christian Kujau <lists@xxxxxxxxxxxxxxx>
> Signed-off-by: Thomas Hebb <tommyhebb@xxxxxxxxx>
> ---
> fs/hfsplus/xattr.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
> index d98094a..da0664e 100644
> --- a/fs/hfsplus/xattr.c
> +++ b/fs/hfsplus/xattr.c
> @@ -28,8 +28,16 @@ const struct xattr_handler *hfsplus_xattr_handlers[] = {
> static int strcmp_xattr_finder_info(const char *name)
> {
> + int err = 0;
> +
> if (name) {
> - return strncmp(name, HFSPLUS_XATTR_FINDER_INFO_NAME,
> + err = strncmp(name, XATTR_MAC_OSX_PREFIX,
> + XATTR_MAC_OSX_PREFIX_LEN);
> + if (err)
> + return err;
> +
> + return strncmp(name + XATTR_MAC_OSX_PREFIX_LEN,
> + HFSPLUS_XATTR_FINDER_INFO_NAME,
> sizeof(HFSPLUS_XATTR_FINDER_INFO_NAME));
> }
> return -1;
> --
> 2.3.4
>
Your patch does fix a bug (reproduced through
listxattr/getxattr/setxattr apis). But I'd recommend a more elegant
code:
--- a/fs/hfsplus/xattr.c
+++ b/fs/hfsplus/xattr.c
@@ -29,7 +29,9 @@ const struct xattr_handler *hfsplus_xattr_handlers[] = {
static int strcmp_xattr_finder_info(const char *name)
{
if (name) {
- return strncmp(name, HFSPLUS_XATTR_FINDER_INFO_NAME,
+ return strncmp(name, XATTR_MAC_OSX_PREFIX
+ HFSPLUS_XATTR_FINDER_INFO_NAME,
+ XATTR_MAC_OSX_PREFIX_LEN +
sizeof(HFSPLUS_XATTR_FINDER_INFO_NAME));
}
return -1;
If you resubmit it, make it Reviewed-by: Sergei Antonov <saproj@xxxxxxxxx>
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