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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id c5sm3111954pfn.144.2021.06.16.13.19.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Jun 2021 13:19:43 -0700 (PDT) From: Kees Cook To: Heiko Carstens Cc: Kees Cook , Julian Wiedmann , Karsten Graul , "David S. Miller" , Jakub Kicinski , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH] s390: iucv: Avoid field over-reading memcpy() Date: Wed, 16 Jun 2021 13:19:42 -0700 Message-Id: <20210616201942.1246211-1-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Patch-Hashes: v=1; h=sha256; g=0981c4eb75dd427d7d91cd99c36bf53addbcfc5d; i=YZOtmOq/sZVNbtRsnkBMD2Kw6M6DcNHBXTl6zJRUyvI=; m=CVqI9jG6YZ9jf8f1ED3Ps1ANOEjrAU1kS6Hl4wF6mU4=; p=5tZ5+WKosX4UV7nN9rSQBm46PiXYBFh/e0B4ynthelY= X-Patch-Sig: m=pgp; i=keescook@chromium.org; s=0x0x8972F4DFDC6DC026; b=iQIzBAABCgAdFiEEpcP2jyKd1g9yPm4TiXL039xtwCYFAmDKXN0ACgkQiXL039xtwCaSnA/+Pcj H3UWanMJVaOTGAEIdXDCjPackgZXSABrZgBCld484XkzWVdo8GRuckbZCt4017+wGCvmoBES96pze OOJzXiG14jyAgv/c7zi6Q6Pdt8zVC+J9syB8vpovW/BYd3WRWbJWet+vyiVwXCFwLteMypdVQjSbD vPqlwtEIhLRIgQJWi7apUcKznj8cupOGcY6fDHrMXjqvk7Ef9nvM5D5I2mfZSjhxvQ6kSciJFTE90 3JNIuLnTh2L4FHQzf2aCR+6uzC6sveKa7LECGTT89TPiGvD0BqBRXfEvhz/gj5gS9iOKVPyUweUhk jV/Ix7tV7MrNl80eNRBtE1wGiGMRkMxckSrp4rWCyPYMLGvV3KszaQY7kwfRh6hOryEGqQifabHUR coGMga1jVG13xKwmqEpcgGJu6+RJ/MWXsw9uMWaV1NZefjZGmqd6x9zOv1SItCyqRceMSoPEQZeC0 VOlihXZ65qlXyXPdJDDWoe0sYlTTxZqhBSgJpnARCCwopTkG5ULwvaR5rXl/W+MUSlVOU/V4/SDn0 Yoo1ryNQjEIdhP7FsUcFA4ywbxOHPfqSW4AiFx3AlhJVDXnaMJtCopNV5jyCFsKSF0xJ45I61WG8L 3cVbIqTzvgqJ4IJcEwrYPdoVeKxae24fWQxBzwGeyIDrzrpSdHxqHSUGFesVyUP4= Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memcpy(), memmove(), and memset(), avoid intentionally reading across neighboring array fields. Add a wrapping struct to serve as the memcpy() source so the compiler can perform appropriate bounds checking, avoiding this future warning: In function '__fortify_memcpy', inlined from 'iucv_message_pending' at net/iucv/iucv.c:1663:4: ./include/linux/fortify-string.h:246:4: error: call to '__read_overflow2_field' declared with attribute error: detected read beyond size of field (2nd parameter) Signed-off-by: Kees Cook --- net/iucv/iucv.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/net/iucv/iucv.c b/net/iucv/iucv.c index 349c6ac3313f..e6795d5a546a 100644 --- a/net/iucv/iucv.c +++ b/net/iucv/iucv.c @@ -1635,14 +1635,16 @@ struct iucv_message_pending { u8 iptype; u32 ipmsgid; u32 iptrgcls; - union { - u32 iprmmsg1_u32; - u8 iprmmsg1[4]; - } ln1msg1; - union { - u32 ipbfln1f; - u8 iprmmsg2[4]; - } ln1msg2; + struct { + union { + u32 iprmmsg1_u32; + u8 iprmmsg1[4]; + } ln1msg1; + union { + u32 ipbfln1f; + u8 iprmmsg2[4]; + } ln1msg2; + } rmmsg; u32 res1[3]; u32 ipbfln2f; u8 ippollfg; @@ -1660,10 +1662,10 @@ static void iucv_message_pending(struct iucv_irq_data *data) msg.id = imp->ipmsgid; msg.class = imp->iptrgcls; if (imp->ipflags1 & IUCV_IPRMDATA) { - memcpy(msg.rmmsg, imp->ln1msg1.iprmmsg1, 8); + memcpy(msg.rmmsg, &imp->rmmsg, 8); msg.length = 8; } else - msg.length = imp->ln1msg2.ipbfln1f; + msg.length = imp->rmmsg.ln1msg2.ipbfln1f; msg.reply_size = imp->ipbfln2f; path->handler->message_pending(path, &msg); } -- 2.25.1