# git rev-parse -q --verify 7685cf1a7140d1cd184e43c747012fa14cb3dd14^{commit} 7685cf1a7140d1cd184e43c747012fa14cb3dd14 already have revision, skipping fetch # git checkout -q -f -B kisskb 7685cf1a7140d1cd184e43c747012fa14cb3dd14 # git clean -qxdf # < git log -1 # commit 7685cf1a7140d1cd184e43c747012fa14cb3dd14 # Author: Alexey Kardashevskiy # Date: Wed Jul 11 21:00:44 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. # # Signed-off-by: Alexey Kardashevskiy # Reviewed-by: Nicholas Piggin # 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 7685cf1a7140d1cd184e43c747012fa14cb3dd14 # < make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-fixes_mvme5100_defconfig_powerpc CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- mvme5100_defconfig # make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-fixes_mvme5100_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/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/ipc/shm.c: In function 'ksys_shmdt': /kisskb/src/ipc/shm.c:1648:59: warning: 'file' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/Makefile:24: CC cannot link executables. Skipping bpfilter. /kisskb/src/fs/udf/unicode.c: In function 'udf_name_conv_char': /kisskb/src/fs/udf/unicode.c:132:8: warning: 'c' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/net/tun.c: In function 'tun_get_user': /kisskb/src/drivers/net/tun.c:1835:30: warning: 'copylen' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/net/tun.c:1545:31: warning: 'linear' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/net/tun.c:1745:46: note: 'linear' 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:246:2: 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 /kisskb/src/net/core/gen_stats.c: In function '__gnet_stats_copy_basic': /kisskb/src/net/core/gen_stats.c:149:19: warning: 'seq' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/core/flow_dissector.c: In function '__skb_flow_dissect': /kisskb/src/net/core/flow_dissector.c:789:7: warning: 'vlan' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/lib/rhashtable.c: In function 'rht_deferred_worker': /kisskb/src/lib/rhashtable.c:269:2: warning: 'next' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/lib/rhashtable.c:234:28: note: 'next' was declared here /kisskb/src/net/core/dev.c: In function 'validate_xmit_skb_list': /kisskb/src/net/core/dev.c:3161:15: warning: 'tail' may be used uninitialized in this function [-Wuninitialized] INFO: Uncompressed kernel (size 0x411ff8) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0x500000) Completed OK # rm -rf /kisskb/build/powerpc-fixes_mvme5100_defconfig_powerpc # Build took: 0:00:18.408154