[Ocfs2-devel] [PATCH] xattr: Constify ->name member of "struct xattr".

[Tetsuo Handa]

Joel Becker wrote:
> I can't really comment on the concept, but if security folks agree, the
> ocfs2 part looks fine.

This is merely a bugfix/cleanup with a bit of cpu usage reduction.

I noticed that EVM by error returns "struct xattr"->name == NULL and
"struct xattr"->value != NULL if kstrdup(XATTR_EVM_SUFFIX, GFP_NOFS) failed,
resulting in EVM security attribute not associated with inode and leak memory.
The proposed (but now turned out to be incorrect) fix is
http://marc.info/?l=linux-security-module&m=136965357007829&w=2 .

But I also noticed that all of SELinux, Smack and EVM sets "struct xattr"->name
a kstrdup()ed constant suffix. Therefore, if passing constant suffix
("const char *") rather than kstrdup()ed constant suffix ("char *") does not
break "struct xattr"->name users, SELinux, Smack and EVM can omit kstrdup()ing
their constant suffix. Therefore, I'm querying you whether changing from
"char *name" to "const char *name" breaks your filesystem.

If my proposal breaks your filesystem, I'm happy to fix only EVM code.

Regards.