# git rev-parse -q --verify 76fa4975f3ed12d15762bc979ca44078598ed8ee^{commit} 76fa4975f3ed12d15762bc979ca44078598ed8ee already have revision, skipping fetch # git checkout -q -f -B kisskb 76fa4975f3ed12d15762bc979ca44078598ed8ee # git clean -qxdf # < git log -1 # commit 76fa4975f3ed12d15762bc979ca44078598ed8ee # Author: Alexey Kardashevskiy # Date: Tue Jul 17 17:19:13 2018 +1000 # # KVM: PPC: Check if IOMMU page is contained in the pinned physical page # # A VM which has: # - a DMA capable device passed through to it (eg. network card); # - running a malicious kernel that ignores H_PUT_TCE failure; # - capability of using IOMMU pages bigger that physical pages # can create an IOMMU mapping that exposes (for example) 16MB of # the host physical memory to the device when only 64K was allocated to the VM. # # The remaining 16MB - 64K will be some other content of host memory, possibly # including pages of the VM, but also pages of host kernel memory, host # programs or other VMs. # # The attacking VM does not control the location of the page it can map, # and is only allowed to map as many pages as it has pages of RAM. # # We already have a check in drivers/vfio/vfio_iommu_spapr_tce.c that # an IOMMU page is contained in the physical page so the PCI hardware won't # get access to unassigned host memory; however this check is missing in # the KVM fastpath (H_PUT_TCE accelerated code). We were lucky so far and # did not hit this yet as the very first time when the mapping happens # we do not have tbl::it_userspace allocated yet and fall back to # the userspace which in turn calls VFIO IOMMU driver, this fails and # the guest does not retry, # # This stores the smallest preregistered page size in the preregistered # region descriptor and changes the mm_iommu_xxx API to check this against # the IOMMU page size. # # This calculates maximum page size as a minimum of the natural region # alignment and compound page size. For the page shift this uses the shift # returned by find_linux_pte() which indicates how the page is mapped to # the current userspace - if the page is huge and this is not a zero, then # it is a leaf pte and the page is mapped within the range. # # Fixes: 121f80ba68f1 ("KVM: PPC: VFIO: Add in-kernel acceleration for VFIO") # Cc: stable@vger.kernel.org # v4.12+ # Signed-off-by: Alexey Kardashevskiy # Reviewed-by: David Gibson # Signed-off-by: Michael Ellerman # < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-gcc --version # < git log --format=%s --max-count=1 76fa4975f3ed12d15762bc979ca44078598ed8ee # < make -s -j 20 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc40x_defconfig_powerpc CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- ppc40x_defconfig # make -s -j 20 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc40x_defconfig_powerpc CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- /kisskb/src/net/Makefile:24: CC cannot link executables. Skipping bpfilter. /kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl': /kisskb/src/kernel/printk/printk.c:183:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/Makefile:24: CC cannot link executables. Skipping bpfilter. /kisskb/src/fs/proc/inode.c: In function 'proc_reg_open': /kisskb/src/include/linux/list.h:65:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/proc/inode.c:339:21: note: 'pdeo' was declared here /kisskb/src/drivers/tty/serial/8250/8250_core.c: In function 'univ8250_release_irq': /kisskb/src/drivers/tty/serial/8250/8250_core.c:251:18: warning: 'i' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/tty/serial/8250/8250_core.c:231:19: note: 'i' was declared here INFO: Uncompressed kernel (size 0x50f780) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0x600000) INFO: Uncompressed kernel (size 0x50f780) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0x600000) INFO: Uncompressed kernel (size 0x50f780) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0x600000) INFO: Uncompressed kernel (size 0x4ff10c) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0x500000) INFO: Uncompressed kernel (size 0x50f780) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0x600000) Image Name: Linux-4.18.0-rc3-g76fa497 Created: Wed Jul 18 19:37:26 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 2527360 Bytes = 2468.12 kB = 2.41 MB Load Address: 00000000 Entry Point: 00000000 Image Name: Linux-4.18.0-rc3-g76fa497 Created: Wed Jul 18 19:37:26 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 2555088 Bytes = 2495.20 kB = 2.44 MB Load Address: 00600000 Entry Point: 00601534 Image Name: Linux-4.18.0-rc3-g76fa497 Created: Wed Jul 18 19:37:27 2018 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 2554291 Bytes = 2494.42 kB = 2.44 MB Load Address: 00600000 Entry Point: 00601350 Completed OK # rm -rf /kisskb/build/powerpc-fixes_ppc40x_defconfig_powerpc # Build took: 0:00:47.279461