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bh=MYkP1BpBixqX8Dh/AxCUn2n9S2MJCM5zMzbJImSDlEI=; b=EtKbNue72EKiLnvB4DflIkAd8k4sPsGm9shAo+AwXThsxLaRv/e2GAoBxlVLUDmBp/h02I HNcNO3ojYaIZO/0f2klUIvOgdRdjw/dSbbu9d4NSQre283nPwg1zJ73x0FcBknMdDOPGAZ bGr3xQL8CLRtlPP6Mp+eGDPdJ8Ovnj0= X-MC-Unique: VX3HjjjTPImuGCNTsUjEeA-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH 1/3] util/iov: add iov_discard_undo() Date: Wed, 12 Aug 2020 11:49:16 +0100 Message-Id: <20200812104918.107116-2-stefanha@redhat.com> In-Reply-To: <20200812104918.107116-1-stefanha@redhat.com> References: <20200812104918.107116-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=stefanha@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=207.211.31.81; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/12 03:52:04 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MIME_BASE64_TEXT=1.741, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-block@nongnu.org, "Michael S. Tsirkin" , Max Reitz , Alexander Bulekov , "Gonglei \(Arei\)" , Stefan Hajnoczi Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" The iov_discard_front/back() operations are useful for parsing iovecs but they modify the array elements. If the original array is needed after parsing finishes there is currently no way to restore it. Although g_memdup() can be used before performing destructive iov_discard_front/back() operations, this is inefficient. Introduce iov_discard_undo() to restore the array to the state prior to an iov_discard_front/back() operation. Signed-off-by: Stefan Hajnoczi Reviewed-by: Li Qiang --- include/qemu/iov.h | 23 +++++++ tests/test-iov.c | 165 +++++++++++++++++++++++++++++++++++++++++++++ util/iov.c | 50 ++++++++++++-- 3 files changed, 234 insertions(+), 4 deletions(-) diff --git a/include/qemu/iov.h b/include/qemu/iov.h index bffc151282..b6b283a5e5 100644 --- a/include/qemu/iov.h +++ b/include/qemu/iov.h @@ -130,6 +130,29 @@ size_t iov_discard_front(struct iovec **iov, unsigned = int *iov_cnt, size_t iov_discard_back(struct iovec *iov, unsigned int *iov_cnt, size_t bytes); =20 +/* Information needed to undo an iov_discard_*() operation */ +typedef struct { + struct iovec *modified_iov; + struct iovec orig; +} IOVDiscardUndo; + +/* + * Undo an iov_discard_front_undoable() or iov_discard_back_undoable() + * operation. If multiple operations are made then each one needs a separa= te + * IOVDiscardUndo and iov_discard_undo() must be called in the reverse ord= er + * that the operations were made. + */ +void iov_discard_undo(IOVDiscardUndo *undo); + +/* + * Undoable versions of iov_discard_front() and iov_discard_back(). Use + * iov_discard_undo() to reset to the state before the discard operations. + */ +size_t iov_discard_front_undoable(struct iovec **iov, unsigned int *iov_cn= t, + size_t bytes, IOVDiscardUndo *undo); +size_t iov_discard_back_undoable(struct iovec *iov, unsigned int *iov_cnt, + size_t bytes, IOVDiscardUndo *undo); + typedef struct QEMUIOVector { struct iovec *iov; int niov; diff --git a/tests/test-iov.c b/tests/test-iov.c index 458ca25099..9c415e2f1f 100644 --- a/tests/test-iov.c +++ b/tests/test-iov.c @@ -26,6 +26,12 @@ static void iov_free(struct iovec *iov, unsigned niov) g_free(iov); } =20 +static bool iov_equals(const struct iovec *a, const struct iovec *b, + unsigned niov) +{ + return memcmp(a, b, sizeof(a[0]) * niov) =3D=3D 0; +} + static void test_iov_bytes(struct iovec *iov, unsigned niov, size_t offset, size_t bytes) { @@ -335,6 +341,87 @@ static void test_discard_front(void) iov_free(iov, iov_cnt); } =20 +static void test_discard_front_undo(void) +{ + IOVDiscardUndo undo; + struct iovec *iov; + struct iovec *iov_tmp; + struct iovec *iov_orig; + unsigned int iov_cnt; + unsigned int iov_cnt_tmp; + size_t size; + + /* Discard zero bytes */ + iov_random(&iov, &iov_cnt); + iov_orig =3D g_memdup(iov, sizeof(iov[0]) * iov_cnt); + iov_tmp =3D iov; + iov_cnt_tmp =3D iov_cnt; + iov_discard_front_undoable(&iov_tmp, &iov_cnt_tmp, 0, &undo); + iov_discard_undo(&undo); + assert(iov_equals(iov, iov_orig, iov_cnt)); + g_free(iov_orig); + iov_free(iov, iov_cnt); + + /* Discard more bytes than vector size */ + iov_random(&iov, &iov_cnt); + iov_orig =3D g_memdup(iov, sizeof(iov[0]) * iov_cnt); + iov_tmp =3D iov; + iov_cnt_tmp =3D iov_cnt; + size =3D iov_size(iov, iov_cnt); + iov_discard_front_undoable(&iov_tmp, &iov_cnt_tmp, size + 1, &undo); + iov_discard_undo(&undo); + assert(iov_equals(iov, iov_orig, iov_cnt)); + g_free(iov_orig); + iov_free(iov, iov_cnt); + + /* Discard entire vector */ + iov_random(&iov, &iov_cnt); + iov_orig =3D g_memdup(iov, sizeof(iov[0]) * iov_cnt); + iov_tmp =3D iov; + iov_cnt_tmp =3D iov_cnt; + size =3D iov_size(iov, iov_cnt); + iov_discard_front_undoable(&iov_tmp, &iov_cnt_tmp, size, &undo); + iov_discard_undo(&undo); + assert(iov_equals(iov, iov_orig, iov_cnt)); + g_free(iov_orig); + iov_free(iov, iov_cnt); + + /* Discard within first element */ + iov_random(&iov, &iov_cnt); + iov_orig =3D g_memdup(iov, sizeof(iov[0]) * iov_cnt); + iov_tmp =3D iov; + iov_cnt_tmp =3D iov_cnt; + size =3D g_test_rand_int_range(1, iov->iov_len); + iov_discard_front_undoable(&iov_tmp, &iov_cnt_tmp, size, &undo); + iov_discard_undo(&undo); + assert(iov_equals(iov, iov_orig, iov_cnt)); + g_free(iov_orig); + iov_free(iov, iov_cnt); + + /* Discard entire first element */ + iov_random(&iov, &iov_cnt); + iov_orig =3D g_memdup(iov, sizeof(iov[0]) * iov_cnt); + iov_tmp =3D iov; + iov_cnt_tmp =3D iov_cnt; + iov_discard_front_undoable(&iov_tmp, &iov_cnt_tmp, iov->iov_len, &undo= ); + iov_discard_undo(&undo); + assert(iov_equals(iov, iov_orig, iov_cnt)); + g_free(iov_orig); + iov_free(iov, iov_cnt); + + /* Discard within second element */ + iov_random(&iov, &iov_cnt); + iov_orig =3D g_memdup(iov, sizeof(iov[0]) * iov_cnt); + iov_tmp =3D iov; + iov_cnt_tmp =3D iov_cnt; + size =3D iov->iov_len + g_test_rand_int_range(1, iov[1].iov_len); + iov_discard_front_undoable(&iov_tmp, &iov_cnt_tmp, size, &undo); + iov_discard_undo(&undo); + assert(iov_equals(iov, iov_orig, iov_cnt)); + g_free(iov_orig); + iov_free(iov, iov_cnt); +} + static void test_discard_back(void) { struct iovec *iov; @@ -404,6 +491,82 @@ static void test_discard_back(void) iov_free(iov, iov_cnt); } =20 +static void test_discard_back_undo(void) +{ + IOVDiscardUndo undo; + struct iovec *iov; + struct iovec *iov_orig; + unsigned int iov_cnt; + unsigned int iov_cnt_tmp; + size_t size; + + /* Discard zero bytes */ + iov_random(&iov, &iov_cnt); + iov_orig =3D g_memdup(iov, sizeof(iov[0]) * iov_cnt); + iov_cnt_tmp =3D iov_cnt; + iov_discard_back_undoable(iov, &iov_cnt_tmp, 0, &undo); + iov_discard_undo(&undo); + assert(iov_equals(iov, iov_orig, iov_cnt)); + g_free(iov_orig); + iov_free(iov, iov_cnt); + + /* Discard more bytes than vector size */ + iov_random(&iov, &iov_cnt); + iov_orig =3D g_memdup(iov, sizeof(iov[0]) * iov_cnt); + iov_cnt_tmp =3D iov_cnt; + size =3D iov_size(iov, iov_cnt); + iov_discard_back_undoable(iov, &iov_cnt_tmp, size + 1, &undo); + iov_discard_undo(&undo); + assert(iov_equals(iov, iov_orig, iov_cnt)); + g_free(iov_orig); + iov_free(iov, iov_cnt); + + /* Discard entire vector */ + iov_random(&iov, &iov_cnt); + iov_orig =3D g_memdup(iov, sizeof(iov[0]) * iov_cnt); + iov_cnt_tmp =3D iov_cnt; + size =3D iov_size(iov, iov_cnt); + iov_discard_back_undoable(iov, &iov_cnt_tmp, size, &undo); + iov_discard_undo(&undo); + assert(iov_equals(iov, iov_orig, iov_cnt)); + g_free(iov_orig); + iov_free(iov, iov_cnt); + + /* Discard within last element */ + iov_random(&iov, &iov_cnt); + iov_orig =3D g_memdup(iov, sizeof(iov[0]) * iov_cnt); + iov_cnt_tmp =3D iov_cnt; + size =3D g_test_rand_int_range(1, iov[iov_cnt - 1].iov_len); + iov_discard_back_undoable(iov, &iov_cnt_tmp, size, &undo); + iov_discard_undo(&undo); + assert(iov_equals(iov, iov_orig, iov_cnt)); + g_free(iov_orig); + iov_free(iov, iov_cnt); + + /* Discard entire last element */ + iov_random(&iov, &iov_cnt); + iov_orig =3D g_memdup(iov, sizeof(iov[0]) * iov_cnt); + iov_cnt_tmp =3D iov_cnt; + size =3D iov[iov_cnt - 1].iov_len; + iov_discard_back_undoable(iov, &iov_cnt_tmp, size, &undo); + iov_discard_undo(&undo); + assert(iov_equals(iov, iov_orig, iov_cnt)); + g_free(iov_orig); + iov_free(iov, iov_cnt); + + /* Discard within second-to-last element */ + iov_random(&iov, &iov_cnt); + iov_orig =3D g_memdup(iov, sizeof(iov[0]) * iov_cnt); + iov_cnt_tmp =3D iov_cnt; + size =3D iov[iov_cnt - 1].iov_len + + g_test_rand_int_range(1, iov[iov_cnt - 2].iov_len); + iov_discard_back_undoable(iov, &iov_cnt_tmp, size, &undo); + iov_discard_undo(&undo); + assert(iov_equals(iov, iov_orig, iov_cnt)); + g_free(iov_orig); + iov_free(iov, iov_cnt); +} + int main(int argc, char **argv) { g_test_init(&argc, &argv, NULL); @@ -412,5 +575,7 @@ int main(int argc, char **argv) g_test_add_func("/basic/iov/io", test_io); g_test_add_func("/basic/iov/discard-front", test_discard_front); g_test_add_func("/basic/iov/discard-back", test_discard_back); + g_test_add_func("/basic/iov/discard-front-undo", test_discard_front_un= do); + g_test_add_func("/basic/iov/discard-back-undo", test_discard_back_undo= ); return g_test_run(); } diff --git a/util/iov.c b/util/iov.c index 45ef3043ee..efcf04b445 100644 --- a/util/iov.c +++ b/util/iov.c @@ -636,14 +636,33 @@ void qemu_iovec_clone(QEMUIOVector *dest, const QEMUI= OVector *src, void *buf) } } =20 -size_t iov_discard_front(struct iovec **iov, unsigned int *iov_cnt, - size_t bytes) +void iov_discard_undo(IOVDiscardUndo *undo) +{ + /* Restore original iovec if it was modified */ + if (undo->modified_iov) { + *undo->modified_iov =3D undo->orig; + } +} + +size_t iov_discard_front_undoable(struct iovec **iov, + unsigned int *iov_cnt, + size_t bytes, + IOVDiscardUndo *undo) { size_t total =3D 0; struct iovec *cur; =20 + if (undo) { + undo->modified_iov =3D NULL; + } + for (cur =3D *iov; *iov_cnt > 0; cur++) { if (cur->iov_len > bytes) { + if (undo) { + undo->modified_iov =3D cur; + undo->orig =3D *cur; + } + cur->iov_base +=3D bytes; cur->iov_len -=3D bytes; total +=3D bytes; @@ -659,12 +678,24 @@ size_t iov_discard_front(struct iovec **iov, unsigned= int *iov_cnt, return total; } =20 -size_t iov_discard_back(struct iovec *iov, unsigned int *iov_cnt, - size_t bytes) +size_t iov_discard_front(struct iovec **iov, unsigned int *iov_cnt, + size_t bytes) +{ + return iov_discard_front_undoable(iov, iov_cnt, bytes, NULL); +} + +size_t iov_discard_back_undoable(struct iovec *iov, + unsigned int *iov_cnt, + size_t bytes, + IOVDiscardUndo *undo) { size_t total =3D 0; struct iovec *cur; =20 + if (undo) { + undo->modified_iov =3D NULL; + } + if (*iov_cnt =3D=3D 0) { return 0; } @@ -673,6 +704,11 @@ size_t iov_discard_back(struct iovec *iov, unsigned in= t *iov_cnt, =20 while (*iov_cnt > 0) { if (cur->iov_len > bytes) { + if (undo) { + undo->modified_iov =3D cur; + undo->orig =3D *cur; + } + cur->iov_len -=3D bytes; total +=3D bytes; break; @@ -687,6 +723,12 @@ size_t iov_discard_back(struct iovec *iov, unsigned in= t *iov_cnt, return total; } =20 +size_t iov_discard_back(struct iovec *iov, unsigned int *iov_cnt, + size_t bytes) +{ + return iov_discard_back_undoable(iov, iov_cnt, bytes, NULL); +} + void qemu_iovec_discard_back(QEMUIOVector *qiov, size_t bytes) { size_t total; --=20 2.26.2 From nobody Sat Feb 7 05:13:11 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1597229488; cv=none; d=zohomail.com; s=zohoarc; b=AcWf5pGmgHJiYtghSF0Kb3M2TGSMkebAlCxNqBKlzo6a/6MlyuJdxKUthnvIadlW8EvWkKeSlUUbgc2wYFwL/QcE7Y2RPhPSzWkQlcg/N1sK8C/tmTfuTeotpMVWaTr7TszGwlTKKybdWHc5aPbR0gy9uigsdhb/YVBTUEBswf0= ARC-Message-Signature: i=1; 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Wed, 12 Aug 2020 10:49:42 +0000 (UTC) Received: from localhost (ovpn-114-96.ams2.redhat.com [10.36.114.96]) by smtp.corp.redhat.com (Postfix) with ESMTP id 680015D6BD; Wed, 12 Aug 2020 10:49:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1597229387; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6Qda3Vaxb3fMagrWQzUSiYjYoPiqmFg223xBIY3hy7M=; b=YjP0dcLlJcz+3f5oZceFgk8130R7VeR4uDDhUQM+BuGlI8E/+5C++HRH0DF+gB1523koKa L09w/FsFxQPI+Oc38dnAMvnGDsnZ7YV5JN5RSyCecvoazss0LZVsRP66+nzHsxdBvRgzZ5 PvEOuoqIt5YyBNvcNle2w6c0HBAjZYM= X-MC-Unique: HbNKnpY8PzqngrTssJaHQA-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH 2/3] virtio-blk: undo destructive iov_discard_*() operations Date: Wed, 12 Aug 2020 11:49:17 +0100 Message-Id: <20200812104918.107116-3-stefanha@redhat.com> In-Reply-To: <20200812104918.107116-1-stefanha@redhat.com> References: <20200812104918.107116-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=stefanha@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=205.139.110.61; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/12 04:50:17 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MIME_BASE64_TEXT=1.741, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-block@nongnu.org, "Michael S. Tsirkin" , Max Reitz , Alexander Bulekov , "Gonglei \(Arei\)" , Stefan Hajnoczi Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" Fuzzing discovered that virtqueue_unmap_sg() is being called on modified req->in/out_sg iovecs. This means dma_memory_map() and dma_memory_unmap() calls do not have matching memory addresses. Fuzzing discovered that non-RAM addresses trigger a bug: void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len, bool is_write, hwaddr access_len) { if (buffer !=3D bounce.buffer) { ^^^^^^^^^^^^^^^^^^^^^^^ A modified iov->iov_base is no longer recognized as a bounce buffer and the wrong branch is taken. There are more potential bugs: dirty memory is not tracked correctly and MemoryRegion refcounts can be leaked. Use the new iov_discard_undo() API to restore elem->in/out_sg before virtqueue_push() is called. Reported-by: Alexander Bulekov Buglink: https://bugs.launchpad.net/qemu/+bug/1890360 Fixes: 827805a2492c1bbf1c0712ed18ee069b4ebf3dd6 ("virtio-blk: Convert VirtI= OBlockReq.out to structrue") Signed-off-by: Stefan Hajnoczi --- include/hw/virtio/virtio-blk.h | 2 ++ hw/block/virtio-blk.c | 9 +++++++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h index b1334c3904..0af654cace 100644 --- a/include/hw/virtio/virtio-blk.h +++ b/include/hw/virtio/virtio-blk.h @@ -68,6 +68,8 @@ typedef struct VirtIOBlockReq { int64_t sector_num; VirtIOBlock *dev; VirtQueue *vq; + IOVDiscardUndo inhdr_undo; + IOVDiscardUndo outhdr_undo; struct virtio_blk_inhdr *in; struct virtio_blk_outhdr out; QEMUIOVector qiov; diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index 413783693c..2b7cc3e1c8 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -80,6 +80,8 @@ static void virtio_blk_req_complete(VirtIOBlockReq *req, = unsigned char status) trace_virtio_blk_req_complete(vdev, req, status); =20 stb_p(&req->in->status, status); + iov_discard_undo(&req->inhdr_undo); + iov_discard_undo(&req->outhdr_undo); virtqueue_push(req->vq, &req->elem, req->in_len); if (s->dataplane_started && !s->dataplane_disabled) { virtio_blk_data_plane_notify(s->dataplane, req->vq); @@ -632,10 +634,12 @@ static int virtio_blk_handle_request(VirtIOBlockReq *= req, MultiReqBuffer *mrb) return -1; } =20 - iov_discard_front(&out_iov, &out_num, sizeof(req->out)); + iov_discard_front_undoable(&out_iov, &out_num, sizeof(req->out), + &req->outhdr_undo); =20 if (in_iov[in_num - 1].iov_len < sizeof(struct virtio_blk_inhdr)) { virtio_error(vdev, "virtio-blk request inhdr too short"); + iov_discard_undo(&req->outhdr_undo); return -1; } =20 @@ -644,7 +648,8 @@ static int virtio_blk_handle_request(VirtIOBlockReq *re= q, MultiReqBuffer *mrb) req->in =3D (void *)in_iov[in_num - 1].iov_base + in_iov[in_num - 1].iov_len - sizeof(struct virtio_blk_inhdr); - iov_discard_back(in_iov, &in_num, sizeof(struct virtio_blk_inhdr)); + iov_discard_back_undoable(in_iov, &in_num, sizeof(struct virtio_blk_in= hdr), + &req->inhdr_undo); =20 type =3D virtio_ldl_p(vdev, &req->out.type); =20 --=20 2.26.2 From nobody Sat Feb 7 05:13:11 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1597229494; cv=none; d=zohomail.com; s=zohoarc; b=cekDJTqiQrUGyG9bOhocrmRASyEx/iH3kjOfn9juYk3sqrdWtdz8aKz+9MyrftbbFeA8JlqTl+cW28CgznkUUSpqILAOUORilMaoEs5ShpAzyMhqdV5Pgi8/F7fbzK+zOdAGTfjaZ523P2QG+hswP+Icmm4OvVojSiCWIGKSOXI= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1597229494; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; 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Wed, 12 Aug 2020 06:49:51 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:29422 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1k5oKK-0007AI-KN for qemu-devel@nongnu.org; Wed, 12 Aug 2020 06:49:51 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-93-1niw20NON0-i_PXqcQxOJw-1; Wed, 12 Aug 2020 06:49:46 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E4F1C101C8A0; Wed, 12 Aug 2020 10:49:44 +0000 (UTC) Received: from localhost (ovpn-114-96.ams2.redhat.com [10.36.114.96]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7CF4060C84; Wed, 12 Aug 2020 10:49:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1597229388; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jQ45tqp8SaqX8OfuFH3rp5Q3ZXUef2GT5+Omm/cVV9g=; b=C+VwDs5YtisYavIdndrAVJ19R5VCusq3J11vWPtgQgFqng+/+t18/XxgXZ/ufR/LE7LKAj ZGSzgAGvouhYgSklO+o+a9Tf06Fs7/SyuDorKNTIgcq/UTfPdhEEnPm9nWCCcpph1Raa/t GovL1ENArp9UbUYtaaB4hjwlE6d2o3I= X-MC-Unique: 1niw20NON0-i_PXqcQxOJw-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH 3/3] virtio-crypto: don't modify elem->in/out_sg Date: Wed, 12 Aug 2020 11:49:18 +0100 Message-Id: <20200812104918.107116-4-stefanha@redhat.com> In-Reply-To: <20200812104918.107116-1-stefanha@redhat.com> References: <20200812104918.107116-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=stefanha@redhat.com X-Mimecast-Spam-Score: 0.001 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=207.211.31.120; envelope-from=stefanha@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/12 06:16:38 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -13 X-Spam_score: -1.4 X-Spam_bar: - X-Spam_report: (-1.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MIME_BASE64_TEXT=1.741, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-block@nongnu.org, "Michael S. Tsirkin" , Max Reitz , Alexander Bulekov , "Gonglei \(Arei\)" , Stefan Hajnoczi Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" A number of iov_discard_front/back() operations are made by virtio-crypto. The elem->in/out_sg iovec arrays are modified by these operations, resulting virtqueue_unmap_sg() calls on different addresses than were originally mapped. This is problematic because dirty memory may not be logged correctly, MemoryRegion refcounts may be leaked, and the non-RAM bounce buffer can be leaked. Take a copy of the elem->in/out_sg arrays so that the originals are preserved. The iov_discard_undo() API could be used instead (with better performance) but requires careful auditing of the code, so do the simple thing instead. Signed-off-by: Stefan Hajnoczi Reviewed-by: Li Qiang --- hw/virtio/virtio-crypto.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/hw/virtio/virtio-crypto.c b/hw/virtio/virtio-crypto.c index 6da12e315f..54f9bbb789 100644 --- a/hw/virtio/virtio-crypto.c +++ b/hw/virtio/virtio-crypto.c @@ -228,6 +228,8 @@ static void virtio_crypto_handle_ctrl(VirtIODevice *vde= v, VirtQueue *vq) size_t s; =20 for (;;) { + g_autofree struct iovec *out_iov_copy =3D NULL; + elem =3D virtqueue_pop(vq, sizeof(VirtQueueElement)); if (!elem) { break; @@ -240,9 +242,12 @@ static void virtio_crypto_handle_ctrl(VirtIODevice *vd= ev, VirtQueue *vq) } =20 out_num =3D elem->out_num; - out_iov =3D elem->out_sg; + out_iov_copy =3D g_memdup(elem->out_sg, sizeof(out_iov[0]) * out_n= um); + out_iov =3D out_iov_copy; + in_num =3D elem->in_num; in_iov =3D elem->in_sg; + if (unlikely(iov_to_buf(out_iov, out_num, 0, &ctrl, sizeof(ctrl)) !=3D sizeof(ctrl))) { virtio_error(vdev, "virtio-crypto request ctrl_hdr too short"); @@ -582,6 +587,8 @@ virtio_crypto_handle_request(VirtIOCryptoReq *request) int queue_index =3D virtio_crypto_vq2q(virtio_get_queue_index(request-= >vq)); struct virtio_crypto_op_data_req req; int ret; + g_autofree struct iovec *in_iov_copy =3D NULL; + g_autofree struct iovec *out_iov_copy =3D NULL; struct iovec *in_iov; struct iovec *out_iov; unsigned in_num; @@ -598,9 +605,13 @@ virtio_crypto_handle_request(VirtIOCryptoReq *request) } =20 out_num =3D elem->out_num; - out_iov =3D elem->out_sg; + out_iov_copy =3D g_memdup(elem->out_sg, sizeof(out_iov[0]) * out_num); + out_iov =3D out_iov_copy; + in_num =3D elem->in_num; - in_iov =3D elem->in_sg; + in_iov_copy =3D g_memdup(elem->in_sg, sizeof(in_iov[0]) * in_num); + in_iov =3D in_iov_copy; + if (unlikely(iov_to_buf(out_iov, out_num, 0, &req, sizeof(req)) !=3D sizeof(req))) { virtio_error(vdev, "virtio-crypto request outhdr too short"); --=20 2.26.2