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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id h3-20020a62b403000000b0050dc7628181sm7143868pfn.91.2022.05.03.18.57.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 May 2022 18:57:42 -0700 (PDT) From: Kees Cook To: "Gustavo A . R . Silva" Cc: Kees Cook , Steffen Klassert , Herbert Xu , "David S. Miller" , Paul Moore , Stephen Smalley , Eric Paris , Nick Desaulniers , Xiu Jianfeng , =?utf-8?q?Christian_G=C3=B6ttsche?= , netdev@vger.kernel.org, selinux@vger.kernel.org, Alexei Starovoitov , alsa-devel@alsa-project.org, Al Viro , Andrew Gabbasov , Andrew Morton , Andy Gross , Andy Lavr , Arend van Spriel , Baowen Zheng , Bjorn Andersson , Boris Ostrovsky , Bradley Grove , brcm80211-dev-list.pdl@broadcom.com, Christian Brauner , Christian Lamparter , Chris Zankel , Cong Wang , Daniel Axtens , Daniel Vetter , Dan Williams , David Gow , David Howells , Dennis Dalessandro , devicetree@vger.kernel.org, Dexuan Cui , Dmitry Kasatkin , Eli Cohen , Eric Dumazet , Eugeniu Rosca , Felipe Balbi , Francis Laniel , Frank Rowand , Franky Lin , Greg Kroah-Hartman , Gregory Greenman , Guenter Roeck , Haiyang Zhang , Hante Meuleman , Hulk Robot , Jakub Kicinski , "James E.J. Bottomley" , James Morris , Jarkko Sakkinen , Jaroslav Kysela , Jason Gunthorpe , Jens Axboe , Johan Hedberg , Johannes Berg , Johannes Berg , John Keeping , Juergen Gross , Kalle Valo , Keith Packard , keyrings@vger.kernel.org, kunit-dev@googlegroups.com, Kuniyuki Iwashima , "K. Y. Srinivasan" , Lars-Peter Clausen , Lee Jones , Leon Romanovsky , Liam Girdwood , linux1394-devel@lists.sourceforge.net, linux-afs@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-bluetooth@vger.kernel.org, linux-hardening@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-integrity@vger.kernel.org, linux-rdma@vger.kernel.org, linux-scsi@vger.kernel.org, linux-security-module@vger.kernel.org, linux-usb@vger.kernel.org, linux-wireless@vger.kernel.org, linux-xtensa@linux-xtensa.org, llvm@lists.linux.dev, Loic Poulain , Louis Peens , Luca Coelho , Luiz Augusto von Dentz , Marc Dionne , Marcel Holtmann , Mark Brown , "Martin K. Petersen" , Max Filippov , Mimi Zohar , Muchun Song , Nathan Chancellor , =?utf-8?q?Nuno_S=C3=A1?= , Paolo Abeni , Rich Felker , Rob Herring , Russell King , "Serge E. Hallyn" , SHA-cyfmac-dev-list@infineon.com, Simon Horman , Stefano Stabellini , Stefan Richter , Stephen Hemminger , Tadeusz Struk , Takashi Iwai , Tom Rix , Udipto Goswami , Vincenzo Frascino , wcn36xx@lists.infradead.org, Wei Liu , xen-devel@lists.xenproject.org, Yang Yingliang Subject: [PATCH 28/32] selinux: Use mem_to_flex_dup() with xfrm and sidtab Date: Tue, 3 May 2022 18:44:37 -0700 Message-Id: <20220504014440.3697851-29-keescook@chromium.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220504014440.3697851-1-keescook@chromium.org> References: <20220504014440.3697851-1-keescook@chromium.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3696; h=from:subject; bh=lo77E+k1d7CC41pTHDyzxO7V17zZAZU2RAD4DG2zlf8=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBicdqHYGDosyWmB9LoZ/xyfTluExkJdmxRYXDGGUpK LWQR5yOJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCYnHahwAKCRCJcvTf3G3AJtEtD/ 9q7isByvmnLJbF2Mqtm1GQLY5WfrgpLpjGz0wPZPFjTuIQg5cBR9sDT+aFaBgykC00RI3PI08gsS9x JTi9K5ZLLk5xSHCb0CjZKLo+ARF0awusiFxdJwvbSdnvd44xlkRwQcTwLZJVGqr2yqy1jJvW1u/3Yh ZZdqt4uhJJpDu5ukdXw+OwIsu09yrTMufSFBgGUsU5+73BimHVDJD+/bAZBGxLMHaKK06iBuF62hS+ XVkvSjBaytrB7eplhA3FHdoU+z/LeETfQYkjmOeYJe6qC/4XyTzzuTjmlkj3sUYna+gIZzZHw5lCgK e8ZKUtmmyjY5P/B2T6F7kreBUKh5iZLQ2r0VwfwJfpJuk13DSHdvjCQuhl4Gt013zBd9fWhQZJesS5 o9IMVFaMGKiFrS1RpL2iZHNi9XVb32DwtShUKjyeEw7ioOL0wYGhna0Kp6zzMgnwjmSeJYnd7Rpifr zM2tyFEjE6tpop237tnM6UbRdzm3XRg4GDWTpvqG9hsvcQcDOk1Wp2/aCUi8Xgzl8dNl2Fr8PklFs5 z9ZW1ImUkK8q5k+Zy0o0VYflt1WZnHugXEEA8b/AT3xAXNqa3BayfVHOM7lLNNWJLV4rSY9HRRJDtf tRpTY3p7aW3hTdJeb21upjhDTPNqM9cBLjUh0Pb2AymaADYZ1hqLMPlC3M+Q== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.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 Cc: Herbert Xu Cc: "David S. Miller" Cc: Paul Moore Cc: Stephen Smalley Cc: Eric Paris Cc: Nick Desaulniers Cc: Xiu Jianfeng Cc: "Christian Göttsche" Cc: netdev@vger.kernel.org Cc: selinux@vger.kernel.org Signed-off-by: Kees Cook --- 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);