From dc91e39e6a5c117a2fec7afc2bab683ff0ab096a Mon Sep 17 00:00:00 2001 From: Steve Sakoman Date: Tue, 27 Oct 2020 06:45:19 -1000 Subject: [PATCH] qemu: fix CVE-2019-20175 CVE: CVE-2019-20175 Signed-off-by: Steve Sakoman --- meta/recipes-devtools/qemu/qemu.inc | 1 + .../qemu/qemu/CVE-2019-20175.patch | 94 +++++++++++++++++++ 2 files changed, 95 insertions(+) create mode 100644 meta/recipes-devtools/qemu/qemu/CVE-2019-20175.patch diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc index 76f97eef35..b6941403ea 100644 --- a/meta/recipes-devtools/qemu/qemu.inc +++ b/meta/recipes-devtools/qemu/qemu.inc @@ -49,6 +49,7 @@ SRC_URI = "https://download.qemu.org/${BPN}-${PV}.tar.xz \ file://CVE-2020-14415.patch \ file://CVE-2020-16092.patch \ file://0001-target-mips-Increase-number-of-TLB-entries-on-the-34.patch \ + file://CVE-2019-20175.patch \ " UPSTREAM_CHECK_REGEX = "qemu-(?P\d+(\.\d+)+)\.tar" diff --git a/meta/recipes-devtools/qemu/qemu/CVE-2019-20175.patch b/meta/recipes-devtools/qemu/qemu/CVE-2019-20175.patch new file mode 100644 index 0000000000..cbbb6d094c --- /dev/null +++ b/meta/recipes-devtools/qemu/qemu/CVE-2019-20175.patch @@ -0,0 +1,94 @@ +From ed78352a59ea7acf7520d4d47a96b9911bae7fc3 Mon Sep 17 00:00:00 2001 +From: Alexander Popov +Date: Mon, 23 Dec 2019 20:51:16 +0300 +Subject: [PATCH] ide: Fix incorrect handling of some PRDTs in ide_dma_cb() + +The commit a718978ed58a from July 2015 introduced the assertion which +implies that the size of successful DMA transfers handled in ide_dma_cb() +should be multiple of 512 (the size of a sector). But guest systems can +initiate DMA transfers that don't fit this requirement. + +For fixing that let's check the number of bytes prepared for the transfer +by the prepare_buf() handler. The code in ide_dma_cb() must behave +according to the Programming Interface for Bus Master IDE Controller +(Revision 1.0 5/16/94): +1. If PRDs specified a smaller size than the IDE transfer + size, then the Interrupt and Active bits in the Controller + status register are not set (Error Condition). +2. If the size of the physical memory regions was equal to + the IDE device transfer size, the Interrupt bit in the + Controller status register is set to 1, Active bit is set to 0. +3. If PRDs specified a larger size than the IDE transfer size, + the Interrupt and Active bits in the Controller status register + are both set to 1. + +Signed-off-by: Alexander Popov +Reviewed-by: Kevin Wolf +Message-id: 20191223175117.508990-2-alex.popov@linux.com +Signed-off-by: John Snow + +Upstream-Status: Backport +CVE: CVE-2019-20175 +Signed-off-by: Steve Sakoman + +--- + hw/ide/core.c | 30 ++++++++++++++++++++++-------- + 1 file changed, 22 insertions(+), 8 deletions(-) + +diff --git a/hw/ide/core.c b/hw/ide/core.c +index 754ff4dc343..80000eb7661 100644 +--- a/hw/ide/core.c ++++ b/hw/ide/core.c +@@ -849,6 +849,7 @@ static void ide_dma_cb(void *opaque, int ret) + int64_t sector_num; + uint64_t offset; + bool stay_active = false; ++ int32_t prep_size = 0; + + if (ret == -EINVAL) { + ide_dma_error(s); +@@ -863,13 +864,15 @@ static void ide_dma_cb(void *opaque, int ret) + } + } + +- n = s->io_buffer_size >> 9; +- if (n > s->nsector) { +- /* The PRDs were longer than needed for this request. Shorten them so +- * we don't get a negative remainder. The Active bit must remain set +- * after the request completes. */ ++ if (s->io_buffer_size > s->nsector * 512) { ++ /* ++ * The PRDs were longer than needed for this request. ++ * The Active bit must remain set after the request completes. ++ */ + n = s->nsector; + stay_active = true; ++ } else { ++ n = s->io_buffer_size >> 9; + } + + sector_num = ide_get_sector(s); +@@ -892,9 +895,20 @@ static void ide_dma_cb(void *opaque, int ret) + n = s->nsector; + s->io_buffer_index = 0; + s->io_buffer_size = n * 512; +- if (s->bus->dma->ops->prepare_buf(s->bus->dma, s->io_buffer_size) < 512) { +- /* The PRDs were too short. Reset the Active bit, but don't raise an +- * interrupt. */ ++ prep_size = s->bus->dma->ops->prepare_buf(s->bus->dma, s->io_buffer_size); ++ /* prepare_buf() must succeed and respect the limit */ ++ assert(prep_size >= 0 && prep_size <= n * 512); ++ ++ /* ++ * Now prep_size stores the number of bytes in the sglist, and ++ * s->io_buffer_size stores the number of bytes described by the PRDs. ++ */ ++ ++ if (prep_size < n * 512) { ++ /* ++ * The PRDs are too short for this request. Error condition! ++ * Reset the Active bit and don't raise the interrupt. ++ */ + s->status = READY_STAT | SEEK_STAT; + dma_buf_commit(s, 0); + goto eot; -- 2.40.1