Ubuntu: (Multiple Advisories) (CVE-2024-45025): Linux kernel vulnerabilities
Description
In the Linux kernel, the following vulnerability has been resolved: fix bitmap corruption on close_range() with CLOSE_RANGE_UNSHARE copy_fd_bitmaps(new, old, count) is expected to copy the first count/BITS_PER_LONG bits from old->full_fds_bits[] and fill the rest with zeroes. What it does is copying enough words (BITS_TO_LONGS(count/BITS_PER_LONG)), then memsets the rest. That works fine, *if* all bits past the cutoff point are clear. Otherwise we are risking garbage from the last word we'd copied. For most of the callers that is true - expand_fdtable() has count equal to old->max_fds, so there's no open descriptors past count, let alone fully occupied words in ->open_fds[], which is what bits in ->full_fds_bits[] correspond to. The other caller (dup_fd()) passes sane_fdtable_size(old_fdt, max_fds), which is the smallest multiple of BITS_PER_LONG that covers all opened descriptors below max_fds. In the common case (copying on fork()) max_fds is ~0U, so all opened descriptors will be below it and we are fine, by the same reasons why the call in expand_fdtable() is safe. Unfortunately, there is a case where max_fds is less than that and where we might, indeed, end up with junk in ->full_fds_bits[] - close_range(from, to, CLOSE_RANGE_UNSHARE) with * descriptor table being currently shared * 'to' being above the current capacity of descriptor table * 'from' being just under some chunk of opened descriptors. In that case we end up with observably wrong behaviour - e.g. spawn a child with CLONE_FILES, get all descriptors in range 0..127 open, then close_range(64, ~0U, CLOSE_RANGE_UNSHARE) and watch dup(0) ending up with descriptor #128, despite #64 being observably not open. The minimally invasive fix would be to deal with that in dup_fd(). If this proves to add measurable overhead, we can go that way, but let's try to fix copy_fd_bitmaps() first. * new helper: bitmap_copy_and_expand(to, from, bits_to_copy, size). * make copy_fd_bitmaps() take the bitmap size in words, rather than bits; it's 'count' argument is always a multiple of BITS_PER_LONG, so we are not losing any information, and that way we can use the same helper for all three bitmaps - compiler will see that count is a multiple of BITS_PER_LONG for the large ones, so it'll generate plain memcpy()+memset(). Reproducer added to tools/testing/selftests/core/close_range_test.c
Solution(s)
- ubuntu-upgrade-linux-image-5-15-0-1038-xilinx-zynqmp
- ubuntu-upgrade-linux-image-5-15-0-1055-gkeop
- ubuntu-upgrade-linux-image-5-15-0-1065-ibm
- ubuntu-upgrade-linux-image-5-15-0-1065-raspi
- ubuntu-upgrade-linux-image-5-15-0-1067-intel-iotg
- ubuntu-upgrade-linux-image-5-15-0-1067-nvidia
- ubuntu-upgrade-linux-image-5-15-0-1067-nvidia-lowlatency
- ubuntu-upgrade-linux-image-5-15-0-1069-gke
- ubuntu-upgrade-linux-image-5-15-0-1069-kvm
- ubuntu-upgrade-linux-image-5-15-0-1070-oracle
- ubuntu-upgrade-linux-image-5-15-0-1071-gcp
- ubuntu-upgrade-linux-image-5-15-0-1072-aws
- ubuntu-upgrade-linux-image-5-15-0-1075-azure
- ubuntu-upgrade-linux-image-5-15-0-125-generic
- ubuntu-upgrade-linux-image-5-15-0-125-generic-64k
- ubuntu-upgrade-linux-image-5-15-0-125-generic-lpae
- ubuntu-upgrade-linux-image-5-15-0-125-lowlatency
- ubuntu-upgrade-linux-image-5-15-0-125-lowlatency-64k
- ubuntu-upgrade-linux-image-5-4-0-1044-iot
- ubuntu-upgrade-linux-image-5-4-0-1054-xilinx-zynqmp
- ubuntu-upgrade-linux-image-5-4-0-1082-ibm
- ubuntu-upgrade-linux-image-5-4-0-1094-bluefield
- ubuntu-upgrade-linux-image-5-4-0-1102-gkeop
- ubuntu-upgrade-linux-image-5-4-0-1119-raspi
- ubuntu-upgrade-linux-image-5-4-0-1123-kvm
- ubuntu-upgrade-linux-image-5-4-0-1134-oracle
- ubuntu-upgrade-linux-image-5-4-0-1135-aws
- ubuntu-upgrade-linux-image-5-4-0-1139-azure
- ubuntu-upgrade-linux-image-5-4-0-1139-gcp
- ubuntu-upgrade-linux-image-5-4-0-1140-azure
- ubuntu-upgrade-linux-image-5-4-0-200-generic
- ubuntu-upgrade-linux-image-5-4-0-200-generic-lpae
- ubuntu-upgrade-linux-image-5-4-0-200-lowlatency
- ubuntu-upgrade-linux-image-6-8-0-1002-gkeop
- ubuntu-upgrade-linux-image-6-8-0-1015-gke
- ubuntu-upgrade-linux-image-6-8-0-1016-raspi
- ubuntu-upgrade-linux-image-6-8-0-1017-ibm
- ubuntu-upgrade-linux-image-6-8-0-1017-oracle
- ubuntu-upgrade-linux-image-6-8-0-1017-oracle-64k
- ubuntu-upgrade-linux-image-6-8-0-1018-oem
- ubuntu-upgrade-linux-image-6-8-0-1019-gcp
- ubuntu-upgrade-linux-image-6-8-0-1019-nvidia
- ubuntu-upgrade-linux-image-6-8-0-1019-nvidia-64k
- ubuntu-upgrade-linux-image-6-8-0-1019-nvidia-lowlatency
- ubuntu-upgrade-linux-image-6-8-0-1019-nvidia-lowlatency-64k
- ubuntu-upgrade-linux-image-6-8-0-1020-aws
- ubuntu-upgrade-linux-image-6-8-0-50-generic
- ubuntu-upgrade-linux-image-6-8-0-50-generic-64k
- ubuntu-upgrade-linux-image-6-8-0-50-lowlatency
- ubuntu-upgrade-linux-image-6-8-0-50-lowlatency-64k
- ubuntu-upgrade-linux-image-aws
- ubuntu-upgrade-linux-image-aws-lts-20-04
- ubuntu-upgrade-linux-image-aws-lts-22-04
- ubuntu-upgrade-linux-image-azure
- ubuntu-upgrade-linux-image-azure-lts-20-04
- ubuntu-upgrade-linux-image-azure-lts-22-04
- ubuntu-upgrade-linux-image-bluefield
- ubuntu-upgrade-linux-image-gcp
- ubuntu-upgrade-linux-image-gcp-lts-20-04
- ubuntu-upgrade-linux-image-gcp-lts-22-04
- ubuntu-upgrade-linux-image-generic
- ubuntu-upgrade-linux-image-generic-64k
- ubuntu-upgrade-linux-image-generic-64k-hwe-20-04
- ubuntu-upgrade-linux-image-generic-64k-hwe-24-04
- ubuntu-upgrade-linux-image-generic-hwe-18-04
- ubuntu-upgrade-linux-image-generic-hwe-20-04
- ubuntu-upgrade-linux-image-generic-hwe-24-04
- ubuntu-upgrade-linux-image-generic-lpae
- ubuntu-upgrade-linux-image-generic-lpae-hwe-20-04
- ubuntu-upgrade-linux-image-gke
- ubuntu-upgrade-linux-image-gke-5-15
- ubuntu-upgrade-linux-image-gkeop
- ubuntu-upgrade-linux-image-gkeop-5-15
- ubuntu-upgrade-linux-image-gkeop-5-4
- ubuntu-upgrade-linux-image-gkeop-6-8
- ubuntu-upgrade-linux-image-ibm
- ubuntu-upgrade-linux-image-ibm-classic
- ubuntu-upgrade-linux-image-ibm-lts-20-04
- ubuntu-upgrade-linux-image-ibm-lts-24-04
- ubuntu-upgrade-linux-image-intel
- ubuntu-upgrade-linux-image-intel-iotg
- ubuntu-upgrade-linux-image-kvm
- ubuntu-upgrade-linux-image-lowlatency
- ubuntu-upgrade-linux-image-lowlatency-64k
- ubuntu-upgrade-linux-image-lowlatency-64k-hwe-20-04
- ubuntu-upgrade-linux-image-lowlatency-64k-hwe-22-04
- ubuntu-upgrade-linux-image-lowlatency-64k-hwe-24-04
- ubuntu-upgrade-linux-image-lowlatency-hwe-18-04
- ubuntu-upgrade-linux-image-lowlatency-hwe-20-04
- ubuntu-upgrade-linux-image-lowlatency-hwe-22-04
- ubuntu-upgrade-linux-image-lowlatency-hwe-24-04
- ubuntu-upgrade-linux-image-nvidia
- ubuntu-upgrade-linux-image-nvidia-6-8
- ubuntu-upgrade-linux-image-nvidia-64k
- ubuntu-upgrade-linux-image-nvidia-64k-6-8
- ubuntu-upgrade-linux-image-nvidia-64k-hwe-22-04
- ubuntu-upgrade-linux-image-nvidia-hwe-22-04
- ubuntu-upgrade-linux-image-nvidia-lowlatency
- ubuntu-upgrade-linux-image-nvidia-lowlatency-64k
- ubuntu-upgrade-linux-image-oem
- ubuntu-upgrade-linux-image-oem-20-04
- ubuntu-upgrade-linux-image-oem-20-04b
- ubuntu-upgrade-linux-image-oem-20-04c
- ubuntu-upgrade-linux-image-oem-20-04d
- ubuntu-upgrade-linux-image-oem-24-04
- ubuntu-upgrade-linux-image-oem-24-04a
- ubuntu-upgrade-linux-image-oem-osp1
- ubuntu-upgrade-linux-image-oracle
- ubuntu-upgrade-linux-image-oracle-64k
- ubuntu-upgrade-linux-image-oracle-lts-20-04
- ubuntu-upgrade-linux-image-oracle-lts-22-04
- ubuntu-upgrade-linux-image-raspi
- ubuntu-upgrade-linux-image-raspi-hwe-18-04
- ubuntu-upgrade-linux-image-raspi-nolpae
- ubuntu-upgrade-linux-image-raspi2
- ubuntu-upgrade-linux-image-snapdragon-hwe-18-04
- ubuntu-upgrade-linux-image-virtual
- ubuntu-upgrade-linux-image-virtual-hwe-18-04
- ubuntu-upgrade-linux-image-virtual-hwe-20-04
- ubuntu-upgrade-linux-image-virtual-hwe-24-04
- ubuntu-upgrade-linux-image-xilinx-zynqmp
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