From acafe7e30216166a17e6e226aadc3ecb63993242 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 8 May 2018 13:45:50 -0700 Subject: treewide: Use struct_size() for kmalloc()-family One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; void *entry[]; }; instance = kmalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL); This patch makes the changes for kmalloc()-family (and kvmalloc()-family) uses. It was done via automatic conversion with manual review for the "CHECKME" non-standard cases noted below, using the following Coccinelle script: // pkey_cache = kmalloc(sizeof *pkey_cache + tprops->pkey_tbl_len * // sizeof *pkey_cache->table, GFP_KERNEL); @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; identifier VAR, ELEMENT; expression COUNT; @@ - alloc(sizeof(*VAR) + COUNT * sizeof(*VAR->ELEMENT), GFP) + alloc(struct_size(VAR, ELEMENT, COUNT), GFP) // mr = kzalloc(sizeof(*mr) + m * sizeof(mr->map[0]), GFP_KERNEL); @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; identifier VAR, ELEMENT; expression COUNT; @@ - alloc(sizeof(*VAR) + COUNT * sizeof(VAR->ELEMENT[0]), GFP) + alloc(struct_size(VAR, ELEMENT, COUNT), GFP) // Same pattern, but can't trivially locate the trailing element name, // or variable name. @@ identifier alloc =~ "kmalloc|kzalloc|kvmalloc|kvzalloc"; expression GFP; expression SOMETHING, COUNT, ELEMENT; @@ - alloc(sizeof(SOMETHING) + COUNT * sizeof(ELEMENT), GFP) + alloc(CHECKME_struct_size(&SOMETHING, ELEMENT, COUNT), GFP) Signed-off-by: Kees Cook --- net/ceph/mon_client.c | 5 ++--- net/ceph/osd_client.c | 3 +-- net/netfilter/xt_recent.c | 3 +-- net/sctp/endpointola.c | 4 ++-- 4 files changed, 6 insertions(+), 9 deletions(-) (limited to 'net') diff --git a/net/ceph/mon_client.c b/net/ceph/mon_client.c index 21ac6e3b96bb..d7a7a2330ef7 100644 --- a/net/ceph/mon_client.c +++ b/net/ceph/mon_client.c @@ -62,7 +62,7 @@ struct ceph_monmap *ceph_monmap_decode(void *p, void *end) if (num_mon > CEPH_MAX_MON) goto bad; - m = kmalloc(sizeof(*m) + sizeof(m->mon_inst[0])*num_mon, GFP_NOFS); + m = kmalloc(struct_size(m, mon_inst, num_mon), GFP_NOFS); if (m == NULL) return ERR_PTR(-ENOMEM); m->fsid = fsid; @@ -1000,8 +1000,7 @@ static int build_initial_monmap(struct ceph_mon_client *monc) int i; /* build initial monmap */ - monc->monmap = kzalloc(sizeof(*monc->monmap) + - num_mon*sizeof(monc->monmap->mon_inst[0]), + monc->monmap = kzalloc(struct_size(monc->monmap, mon_inst, num_mon), GFP_KERNEL); if (!monc->monmap) return -ENOMEM; diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c index ea2a6c9fb7ce..4959260e19fe 100644 --- a/net/ceph/osd_client.c +++ b/net/ceph/osd_client.c @@ -565,8 +565,7 @@ struct ceph_osd_request *ceph_osdc_alloc_request(struct ceph_osd_client *osdc, req = kmem_cache_alloc(ceph_osd_request_cache, gfp_flags); } else { BUG_ON(num_ops > CEPH_OSD_MAX_OPS); - req = kmalloc(sizeof(*req) + num_ops * sizeof(req->r_ops[0]), - gfp_flags); + req = kmalloc(struct_size(req, r_ops, num_ops), gfp_flags); } if (unlikely(!req)) return NULL; diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c index 9bbfc17ce3ec..07085c22b19c 100644 --- a/net/netfilter/xt_recent.c +++ b/net/netfilter/xt_recent.c @@ -184,8 +184,7 @@ recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr, } nstamps_max += 1; - e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * nstamps_max, - GFP_ATOMIC); + e = kmalloc(struct_size(e, stamps, nstamps_max), GFP_ATOMIC); if (e == NULL) return NULL; memcpy(&e->addr, addr, sizeof(e->addr)); diff --git a/net/sctp/endpointola.c b/net/sctp/endpointola.c index e2f5a3ee41a7..40c7eb941bc9 100644 --- a/net/sctp/endpointola.c +++ b/net/sctp/endpointola.c @@ -73,8 +73,8 @@ static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep, * variables. There are arrays that we encode directly * into parameters to make the rest of the operations easier. */ - auth_hmacs = kzalloc(sizeof(*auth_hmacs) + - sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp); + auth_hmacs = kzalloc(struct_size(auth_hmacs, hmac_ids, + SCTP_AUTH_NUM_HMACS), gfp); if (!auth_hmacs) goto nomem; -- cgit v1.2.3