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[PATCH 28/32] selinux: Use mem_to_flex_dup() with xfrm and sidtab
- To: "Gustavo A . R . Silva" <gustavoars@xxxxxxxxxx>
- From: Kees Cook <keescook@xxxxxxxxxxxx>
- Date: Tue, 3 May 2022 18:44:37 -0700
- Cc: Kees Cook <keescook@xxxxxxxxxxxx>, Steffen Klassert <steffen.klassert@xxxxxxxxxxx>, Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>, "David S. Miller" <davem@xxxxxxxxxxxxx>, Paul Moore <paul@xxxxxxxxxxxxxx>, Stephen Smalley <stephen.smalley.work@xxxxxxxxx>, Eric Paris <eparis@xxxxxxxxxxxxxx>, Nick Desaulniers <ndesaulniers@xxxxxxxxxx>, Xiu Jianfeng <xiujianfeng@xxxxxxxxxx>, Christian Göttsche <cgzones@xxxxxxxxxxxxxx>, netdev@xxxxxxxxxxxxxxx, selinux@xxxxxxxxxxxxxxx, Alexei Starovoitov <ast@xxxxxxxxxx>, alsa-devel@xxxxxxxxxxxxxxxx, Al Viro <viro@xxxxxxxxxxxxxxxxxx>, Andrew Gabbasov <andrew_gabbasov@xxxxxxxxxx>, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>, Andy Gross <agross@xxxxxxxxxx>, Andy Lavr <andy.lavr@xxxxxxxxx>, Arend van Spriel <aspriel@xxxxxxxxx>, Baowen Zheng <baowen.zheng@xxxxxxxxxxxx>, Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>, Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>, Bradley Grove <linuxdrivers@xxxxxxxxxxxx>, brcm80211-dev-list.pdl@xxxxxxxxxxxx, Christian Brauner <brauner@xxxxxxxxxx>, Christian Lamparter <chunkeey@xxxxxxxxxxxxxx>, Chris Zankel <chris@xxxxxxxxxx>, Cong Wang <cong.wang@xxxxxxxxxxxxx>, Daniel Axtens <dja@xxxxxxxxxx>, Daniel Vetter <daniel.vetter@xxxxxxxx>, Dan Williams <dan.j.williams@xxxxxxxxx>, David Gow <davidgow@xxxxxxxxxx>, David Howells <dhowells@xxxxxxxxxx>, Dennis Dalessandro <dennis.dalessandro@xxxxxxxxxxxxxxxxxxxx>, devicetree@xxxxxxxxxxxxxxx, Dexuan Cui <decui@xxxxxxxxxxxxx>, Dmitry Kasatkin <dmitry.kasatkin@xxxxxxxxx>, Eli Cohen <elic@xxxxxxxxxx>, Eric Dumazet <edumazet@xxxxxxxxxx>, Eugeniu Rosca <erosca@xxxxxxxxxxxxxx>, Felipe Balbi <balbi@xxxxxxxxxx>, Francis Laniel <laniel_francis@xxxxxxxxxxxxxxxxxxx>, Frank Rowand <frowand.list@xxxxxxxxx>, Franky Lin <franky.lin@xxxxxxxxxxxx>, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>, Gregory Greenman <gregory.greenman@xxxxxxxxx>, Guenter Roeck <linux@xxxxxxxxxxxx>, Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>, Hante Meuleman <hante.meuleman@xxxxxxxxxxxx>, Hulk Robot <hulkci@xxxxxxxxxx>, Jakub Kicinski <kuba@xxxxxxxxxx>, "James E.J. Bottomley" <jejb@xxxxxxxxxxxxx>, James Morris <jmorris@xxxxxxxxx>, Jarkko Sakkinen <jarkko@xxxxxxxxxx>, Jaroslav Kysela <perex@xxxxxxxx>, Jason Gunthorpe <jgg@xxxxxxxx>, Jens Axboe <axboe@xxxxxxxxx>, Johan Hedberg <johan.hedberg@xxxxxxxxx>, Johannes Berg <johannes.berg@xxxxxxxxx>, Johannes Berg <johannes@xxxxxxxxxxxxxxxx>, John Keeping <john@xxxxxxxxxxxx>, Juergen Gross <jgross@xxxxxxxx>, Kalle Valo <kvalo@xxxxxxxxxx>, Keith Packard <keithp@xxxxxxxxxx>, keyrings@xxxxxxxxxxxxxxx, kunit-dev@xxxxxxxxxxxxxxxx, Kuniyuki Iwashima <kuniyu@xxxxxxxxxxxx>, "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>, Lars-Peter Clausen <lars@xxxxxxxxxx>, Lee Jones <lee.jones@xxxxxxxxxx>, Leon Romanovsky <leon@xxxxxxxxxx>, Liam Girdwood <lgirdwood@xxxxxxxxx>, linux1394-devel@xxxxxxxxxxxxxxxxxxxxx, linux-afs@xxxxxxxxxxxxxxxxxxx, linux-arm-kernel@xxxxxxxxxxxxxxxxxxx, linux-arm-msm@xxxxxxxxxxxxxxx, linux-bluetooth@xxxxxxxxxxxxxxx, linux-hardening@xxxxxxxxxxxxxxx, linux-hyperv@xxxxxxxxxxxxxxx, linux-integrity@xxxxxxxxxxxxxxx, linux-rdma@xxxxxxxxxxxxxxx, linux-scsi@xxxxxxxxxxxxxxx, linux-security-module@xxxxxxxxxxxxxxx, linux-usb@xxxxxxxxxxxxxxx, linux-wireless@xxxxxxxxxxxxxxx, linux-xtensa@xxxxxxxxxxxxxxxx, llvm@xxxxxxxxxxxxxxx, Loic Poulain <loic.poulain@xxxxxxxxxx>, Louis Peens <louis.peens@xxxxxxxxxxxx>, Luca Coelho <luciano.coelho@xxxxxxxxx>, Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx>, Marc Dionne <marc.dionne@xxxxxxxxxxxx>, Marcel Holtmann <marcel@xxxxxxxxxxxx>, Mark Brown <broonie@xxxxxxxxxx>, "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>, Max Filippov <jcmvbkbc@xxxxxxxxx>, Mimi Zohar <zohar@xxxxxxxxxxxxx>, Muchun Song <songmuchun@xxxxxxxxxxxxx>, Nathan Chancellor <nathan@xxxxxxxxxx>, Nuno Sá <nuno.sa@xxxxxxxxxx>, Paolo Abeni <pabeni@xxxxxxxxxx>, Rich Felker <dalias@xxxxxxxxxx>, Rob Herring <robh+dt@xxxxxxxxxx>, Russell King <linux@xxxxxxxxxxxxxxx>, "Serge E. Hallyn" <serge@xxxxxxxxxx>, SHA-cyfmac-dev-list@xxxxxxxxxxxx, Simon Horman <simon.horman@xxxxxxxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>, Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>, Tadeusz Struk <tadeusz.struk@xxxxxxxxxx>, Takashi Iwai <tiwai@xxxxxxxx>, Tom Rix <trix@xxxxxxxxxx>, Udipto Goswami <quic_ugoswami@xxxxxxxxxxx>, Vincenzo Frascino <vincenzo.frascino@xxxxxxx>, wcn36xx@xxxxxxxxxxxxxxxxxxx, Wei Liu <wei.liu@xxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx, Yang Yingliang <yangyingliang@xxxxxxxxxx>
- Delivery-date: Wed, 04 May 2022 05:16:52 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
As part of the work to perform bounds checking on all memcpy() uses,
replace the open-coded a deserialization of bytes out of memory into a
trailing flexible array by using a flex_array.h helper to perform the
allocation, bounds checking, and copying:
struct xfrm_sec_ctx
struct sidtab_str_cache
Cc: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Paul Moore <paul@xxxxxxxxxxxxxx>
Cc: Stephen Smalley <stephen.smalley.work@xxxxxxxxx>
Cc: Eric Paris <eparis@xxxxxxxxxxxxxx>
Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Cc: Xiu Jianfeng <xiujianfeng@xxxxxxxxxx>
Cc: "Christian Göttsche" <cgzones@xxxxxxxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Cc: selinux@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
include/uapi/linux/xfrm.h | 4 ++--
security/selinux/ss/sidtab.c | 9 +++------
security/selinux/xfrm.c | 7 ++-----
3 files changed, 7 insertions(+), 13 deletions(-)
diff --git a/include/uapi/linux/xfrm.h b/include/uapi/linux/xfrm.h
index 65e13a099b1a..4a6fa2beff6a 100644
--- a/include/uapi/linux/xfrm.h
+++ b/include/uapi/linux/xfrm.h
@@ -31,9 +31,9 @@ struct xfrm_id {
struct xfrm_sec_ctx {
__u8 ctx_doi;
__u8 ctx_alg;
- __u16 ctx_len;
+ __DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(__u16, ctx_len);
__u32 ctx_sid;
- char ctx_str[0];
+ __DECLARE_FLEX_ARRAY_ELEMENTS(char, ctx_str);
};
/* Security Context Domains of Interpretation */
diff --git a/security/selinux/ss/sidtab.c b/security/selinux/ss/sidtab.c
index a54b8652bfb5..a9d434e8cff7 100644
--- a/security/selinux/ss/sidtab.c
+++ b/security/selinux/ss/sidtab.c
@@ -23,8 +23,8 @@ struct sidtab_str_cache {
struct rcu_head rcu_member;
struct list_head lru_member;
struct sidtab_entry *parent;
- u32 len;
- char str[];
+ DECLARE_FLEX_ARRAY_ELEMENTS_COUNT(u32, len);
+ DECLARE_FLEX_ARRAY_ELEMENTS(char, str);
};
#define index_to_sid(index) ((index) + SECINITSID_NUM + 1)
@@ -570,8 +570,7 @@ void sidtab_sid2str_put(struct sidtab *s, struct
sidtab_entry *entry,
goto out_unlock;
}
- cache = kmalloc(struct_size(cache, str, str_len), GFP_ATOMIC);
- if (!cache)
+ if (mem_to_flex_dup(&cache, str, str_len, GFP_ATOMIC))
goto out_unlock;
if (s->cache_free_slots == 0) {
@@ -584,8 +583,6 @@ void sidtab_sid2str_put(struct sidtab *s, struct
sidtab_entry *entry,
s->cache_free_slots--;
}
cache->parent = entry;
- cache->len = str_len;
- memcpy(cache->str, str, str_len);
list_add(&cache->lru_member, &s->cache_lru_list);
rcu_assign_pointer(entry->cache, cache);
diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c
index c576832febc6..bc7a54bf8f0d 100644
--- a/security/selinux/xfrm.c
+++ b/security/selinux/xfrm.c
@@ -345,7 +345,7 @@ int selinux_xfrm_state_alloc_acquire(struct xfrm_state *x,
struct xfrm_sec_ctx *polsec, u32 secid)
{
int rc;
- struct xfrm_sec_ctx *ctx;
+ struct xfrm_sec_ctx *ctx = NULL;
char *ctx_str = NULL;
u32 str_len;
@@ -360,8 +360,7 @@ int selinux_xfrm_state_alloc_acquire(struct xfrm_state *x,
if (rc)
return rc;
- ctx = kmalloc(struct_size(ctx, ctx_str, str_len), GFP_ATOMIC);
- if (!ctx) {
+ if (mem_to_flex_dup(&ctx, ctx_str, str_len, GFP_ATOMIC)) {
rc = -ENOMEM;
goto out;
}
@@ -369,8 +368,6 @@ int selinux_xfrm_state_alloc_acquire(struct xfrm_state *x,
ctx->ctx_doi = XFRM_SC_DOI_LSM;
ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
ctx->ctx_sid = secid;
- ctx->ctx_len = str_len;
- memcpy(ctx->ctx_str, ctx_str, str_len);
x->security = ctx;
atomic_inc(&selinux_xfrm_refcount);
--
2.32.0
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