[RFC PATCH] lsm,fs: fix vfs_getxattr_alloc() return type and caller error paths

[Paul Moore]

On Wed, Nov 9, 2022 at 11:36 PM Paul Moore <paul at paul-moore.com> wrote:
>
> The vfs_getxattr_alloc() function currently returns a ssize_t value
> despite the fact that it only uses int values internally for return
> values.  Fix this by converting vfs_getxattr_alloc() to return an
> int type and adjust the callers as necessary.  As part of these
> caller modifications, some of the callers are fixed to properly free
> the xattr value buffer on both success and failure to ensure that
> memory is not leaked in the failure case.
>
> Signed-off-by: Paul Moore <paul at paul-moore.com>
> ---
>  fs/xattr.c                                |  5 +++--
>  include/linux/xattr.h                     |  6 +++---
>  security/apparmor/domain.c                |  3 +--
>  security/commoncap.c                      | 22 ++++++++++------------
>  security/integrity/evm/evm_crypto.c       |  5 +++--
>  security/integrity/evm/evm_main.c         |  7 +++++--
>  security/integrity/ima/ima.h              |  5 +++--
>  security/integrity/ima/ima_appraise.c     |  6 +++---
>  security/integrity/ima/ima_main.c         |  6 ++++--
>  security/integrity/ima/ima_template_lib.c | 11 +++++------
>  10 files changed, 40 insertions(+), 36 deletions(-)

Mimi, I'm particularly interested in your thoughts on this patch as
there are a number of places in the IMA/EVM code that needed some
additional tweaks to prevent a memory leak like we fixed in the
capabilities code via 8cf0a1bc1287 ("capabilities: fix potential
memleak on error path from vfs_getxattr_alloc()").

-- 
paul-moore.com