Quoting Kasatkin, Dmitry (dmitry.kasat...@intel.com):
> On Thu, Aug 16, 2012 at 12:11 AM, Kasatkin, Dmitry
> <dmitry.kasat...@intel.com> wrote:
> > On Wed, Aug 15, 2012 at 11:11 PM, Serge Hallyn
> > <serge.hal...@canonical.com> wrote:
> >> Quoting Dmitry Kasatkin (dmitry.kasat...@intel.com):
> >>> There are several functions, that need to calculate digest.
> >>> This patch adds common function for use by integrity subsystem.
> >>>
> >>> Signed-off-by: Dmitry Kasatkin <dmitry.kasat...@intel.com>
> >>> ---
> >>> security/integrity/digsig.c | 31 +++++++++++++++++++++++++++++--
> >>> security/integrity/integrity.h | 3 +++
> >>> 2 files changed, 32 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
> >>> index 2dc167d..61a0c92 100644
> >>> --- a/security/integrity/digsig.c
> >>> +++ b/security/integrity/digsig.c
> >>> @@ -13,9 +13,9 @@
> >>> #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> >>>
> >>> #include <linux/err.h>
> >>> -#include <linux/rbtree.h>
> >>> #include <linux/key-type.h>
> >>> #include <linux/digsig.h>
> >>> +#include <crypto/hash.h>
> >>>
> >>> #include "integrity.h"
> >>>
> >>> @@ -28,7 +28,7 @@ static const char *keyring_name[INTEGRITY_KEYRING_MAX]
> >>> = {
> >>> };
> >>>
> >>> int integrity_digsig_verify(const unsigned int id, const char *sig, int
> >>> siglen,
> >>> - const char *digest, int digestlen)
> >>> + const char *digest, int digestlen)
> >>> {
> >>> if (id >= INTEGRITY_KEYRING_MAX)
> >>> return -EINVAL;
> >>> @@ -46,3 +46,30 @@ int integrity_digsig_verify(const unsigned int id,
> >>> const char *sig, int siglen,
> >>>
> >>> return digsig_verify(keyring[id], sig, siglen, digest, digestlen);
> >>> }
> >>> +
> >>> +int integrity_calc_digest(const char *algo, const void *data, const int
> >>> len,
> >>> + char *digest)
> >>> +{
> >>> + int rc = -ENOMEM;
> >>> + struct crypto_shash *tfm;
> >>> +
> >>> + tfm = crypto_alloc_shash(algo, 0, 0);
> >>> + if (IS_ERR(tfm)) {
> >>> + rc = PTR_ERR(tfm);
> >>> + pr_err("Can not allocate %s (reason: %d)\n", algo, rc);
> >>> + return rc;
> >>> + } else {
> >>> + struct {
> >>> + struct shash_desc shash;
> >>> + char ctx[crypto_shash_descsize(tfm)];
> >>> + } desc;
> >>
> >> Needless confusing indentation here. Just move the struct {} desc; to the
> >> top and drop the else. That will make it much more readable.
> >>
> >
> > Intention was to allocate it only if tfm allocation succeeded..
> > But indeed failure very unlikely..
> >
>
> BTW.. The reason for such code is that ctx member uses function in the
> parameter:
>
> char ctx[crypto_shash_descsize(tfm)];
>
> It is not possible to do it before tfm allocation...
> So I cannot move it up..
Ah, I see. Cool :)
> I can only kmalloc it then.
Well no, you could use another function I suppose.
But if you're going to leave it as is, please at least move the whole
rest of the function into the else{} :) Yes, no functional change,
but a change in how it looks to the eye of someone trying to review
and look for actual free-unallocated-memory errors or leaks.
-serge
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