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[34.91.183.136]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-698ad11892asm1434226a12.20.2026.07.02.13.18.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Jul 2026 13:18:12 -0700 (PDT) Date: Thu, 2 Jul 2026 20:18:08 +0000 From: Matt Bobrowski To: Paul Moore Cc: linux-security-module@vger.kernel.org, James Morris , "Serge E . Hallyn" Subject: Re: [PATCH] lsm: cleanup repeated lsm_blob_size_update() calls in lsm_prepare() Message-ID: References: <20260629210150.832576-1-mattbobrowski@google.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Jul 02, 2026 at 03:15:02PM -0400, Paul Moore wrote: > On Jun 29, 2026 Matt Bobrowski wrote: > > > > Centralize the definition of LSM security blob fields using an X-macro > > (LSM_BLOBS_LIST). This reduces repetitive boilerplate code across > > struct lsm_blob_sizes, blob size registration in lsm_prepare(), and > > debug log printing in security_init(). > > > > Signed-off-by: Matt Bobrowski > > --- > > include/linux/lsm_hooks.h | 42 ++++++++++++++++------------ > > security/lsm_init.c | 59 ++++++++++----------------------------- > > 2 files changed, 38 insertions(+), 63 deletions(-) > > > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > > index b4f8cad53ddb..0e73b22bdeea 100644 > > --- a/include/linux/lsm_hooks.h > > +++ b/include/linux/lsm_hooks.h > > @@ -98,28 +98,34 @@ struct security_hook_list { > > const struct lsm_id *lsmid; > > } __randomize_layout; > > > > +#define LSM_BLOBS_LIST(X) \ > > + X(cred) \ > > + X(file) \ > > + X(backing_file) \ > > + X(ib) \ > > + X(inode) \ > > + X(sock) \ > > + X(superblock) \ > > + X(ipc) \ > > + X(key) \ > > + X(msg_msg) \ > > + X(perf_event) \ > > + X(task) \ > > + X(tun_dev) \ > > + X(xattr_count) \ > > + X(bdev) \ > > + X(bpf_map) \ > > + X(bpf_prog) \ > > + X(bpf_token) > > + > > /* > > * Security blob size or offset data. > > + * Note: lbs_xattr_count is the number of xattr slots in new_xattrs array. > > */ > > struct lsm_blob_sizes { > > - unsigned int lbs_cred; > > - unsigned int lbs_file; > > - unsigned int lbs_backing_file; > > - unsigned int lbs_ib; > > - unsigned int lbs_inode; > > - unsigned int lbs_sock; > > - unsigned int lbs_superblock; > > - unsigned int lbs_ipc; > > - unsigned int lbs_key; > > - unsigned int lbs_msg_msg; > > - unsigned int lbs_perf_event; > > - unsigned int lbs_task; > > - unsigned int lbs_xattr_count; /* num xattr slots in new_xattrs array */ > > - unsigned int lbs_tun_dev; > > - unsigned int lbs_bdev; > > - unsigned int lbs_bpf_map; > > - unsigned int lbs_bpf_prog; > > - unsigned int lbs_bpf_token; > > +#define LSM_BLOB_SIZE(name) unsigned int lbs_##name; > > + LSM_BLOBS_LIST(LSM_BLOB_SIZE); > > +#undef LSM_BLOB_SIZE > > }; > > Generally speaking I greatly prefer to see the structure fields typed out > as it makes it easier to find them using grep, code indexers, etc. There > is a similar argument for the security_init() changes (below). > > > diff --git a/security/lsm_init.c b/security/lsm_init.c > > index 7c0fd17f1601..c256f1c33efa 100644 > > --- a/security/lsm_init.c > > +++ b/security/lsm_init.c > > @@ -282,40 +282,24 @@ static void __init lsm_blob_size_update(unsigned int *sz_req, > > * lsm_prepare - Prepare the LSM framework for a new LSM > > * @lsm: LSM definition > > */ > > -static void __init lsm_prepare(struct lsm_info *lsm) > > +static void __init lsm_prepare(const struct lsm_info *lsm) > > { > > struct lsm_blob_sizes *blobs = lsm->blobs; > > > > if (!blobs) > > return; > > > > - /* Register the LSM blob sizes. */ > > - blobs = lsm->blobs; > > - lsm_blob_size_update(&blobs->lbs_cred, &blob_sizes.lbs_cred); > > - lsm_blob_size_update(&blobs->lbs_file, &blob_sizes.lbs_file); > > - lsm_blob_size_update(&blobs->lbs_backing_file, > > - &blob_sizes.lbs_backing_file); > > - lsm_blob_size_update(&blobs->lbs_ib, &blob_sizes.lbs_ib); > > - /* inode blob gets an rcu_head in addition to LSM blobs. */ > > + /* The inode blob (inode->i_security) gets an rcu_head in addition to > > + * LSM blobs. > > + */ > > if (blobs->lbs_inode && blob_sizes.lbs_inode == 0) > > blob_sizes.lbs_inode = sizeof(struct rcu_head); > > - lsm_blob_size_update(&blobs->lbs_inode, &blob_sizes.lbs_inode); > > - lsm_blob_size_update(&blobs->lbs_ipc, &blob_sizes.lbs_ipc); > > - lsm_blob_size_update(&blobs->lbs_key, &blob_sizes.lbs_key); > > - lsm_blob_size_update(&blobs->lbs_msg_msg, &blob_sizes.lbs_msg_msg); > > - lsm_blob_size_update(&blobs->lbs_perf_event, > > - &blob_sizes.lbs_perf_event); > > - lsm_blob_size_update(&blobs->lbs_sock, &blob_sizes.lbs_sock); > > - lsm_blob_size_update(&blobs->lbs_superblock, > > - &blob_sizes.lbs_superblock); > > - lsm_blob_size_update(&blobs->lbs_task, &blob_sizes.lbs_task); > > - lsm_blob_size_update(&blobs->lbs_tun_dev, &blob_sizes.lbs_tun_dev); > > - lsm_blob_size_update(&blobs->lbs_xattr_count, > > - &blob_sizes.lbs_xattr_count); > > - lsm_blob_size_update(&blobs->lbs_bdev, &blob_sizes.lbs_bdev); > > - lsm_blob_size_update(&blobs->lbs_bpf_map, &blob_sizes.lbs_bpf_map); > > - lsm_blob_size_update(&blobs->lbs_bpf_prog, &blob_sizes.lbs_bpf_prog); > > - lsm_blob_size_update(&blobs->lbs_bpf_token, &blob_sizes.lbs_bpf_token); > > + > > + /* Register the LSM blob sizes. */ > > +#define UPDATE_LSM_BLOB_SIZE(name) \ > > + lsm_blob_size_update(&blobs->lbs_##name, &blob_sizes.lbs_##name); > > + LSM_BLOBS_LIST(UPDATE_LSM_BLOB_SIZE); > > +#undef UPDATE_LSM_BLOB_SIZE > > } > > This is one case where the macro approach *might* have some value, but as > it is the one instance, and multiple sequential blob operations like this > are going to be *very* limited, I'm not sure there is enough value to > be worth the change. > > I appreciate the initiative to search out areas that you think could use > improvement, but for the reasons mentioned, I'm not going to merge this > patch. That's not a problem. Perhaps you may want to consider only taking the minor cleanup targets the redundant lsm->blobs access within lsm_prepare(). > > @@ -441,25 +425,10 @@ int __init security_init(void) > > lsm_prepare(*lsm); > > > > if (lsm_debug) { > > - lsm_pr("blob(cred) size %d\n", blob_sizes.lbs_cred); > > - lsm_pr("blob(file) size %d\n", blob_sizes.lbs_file); > > - lsm_pr("blob(backing_file) size %d\n", > > - blob_sizes.lbs_backing_file); > > - lsm_pr("blob(ib) size %d\n", blob_sizes.lbs_ib); > > - lsm_pr("blob(inode) size %d\n", blob_sizes.lbs_inode); > > - lsm_pr("blob(ipc) size %d\n", blob_sizes.lbs_ipc); > > - lsm_pr("blob(key) size %d\n", blob_sizes.lbs_key); > > - lsm_pr("blob(msg_msg)_size %d\n", blob_sizes.lbs_msg_msg); > > - lsm_pr("blob(sock) size %d\n", blob_sizes.lbs_sock); > > - lsm_pr("blob(superblock) size %d\n", blob_sizes.lbs_superblock); > > - lsm_pr("blob(perf_event) size %d\n", blob_sizes.lbs_perf_event); > > - lsm_pr("blob(task) size %d\n", blob_sizes.lbs_task); > > - lsm_pr("blob(tun_dev) size %d\n", blob_sizes.lbs_tun_dev); > > - lsm_pr("blob(xattr) count %d\n", blob_sizes.lbs_xattr_count); > > - lsm_pr("blob(bdev) size %d\n", blob_sizes.lbs_bdev); > > - lsm_pr("blob(bpf_map) size %d\n", blob_sizes.lbs_bpf_map); > > - lsm_pr("blob(bpf_prog) size %d\n", blob_sizes.lbs_bpf_prog); > > - lsm_pr("blob(bpf_token) size %d\n", blob_sizes.lbs_bpf_token); > > +#define PRINT_LSM_BLOB_SIZE(name) \ > > + lsm_pr("blob(" #name ") size %d\n", blob_sizes.lbs_##name); > > + LSM_BLOBS_LIST(PRINT_LSM_BLOB_SIZE); > > +#undef PRINT_LSM_BLOB_SIZE > > This is another case where having the text string grep'able can be a good > thing. > > -- > paul-moore.com