um: mm: check more comprehensively for stub changes
commit 47da29763ec9a153b9b685bff9db659e4e09e494 upstream.
If userspace tries to change the stub, we need to kill it,
because otherwise it can escape the virtual machine. In a
few cases the stub checks weren't good, e.g. if userspace
just tries to
mmap(0x100000 - 0x1000, 0x3000, ...)
it could succeed to get a new private/anonymous mapping
replacing the stubs. Fix this by checking everywhere, and
checking for _overlap_, not just direct changes.
Cc: stable@vger.kernel.org
Fixes: 3963333fe6
("uml: cover stubs with a VMA")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
b95baf4efb
commit
5b5d760280
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@ -126,6 +126,9 @@ static int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
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struct host_vm_op *last;
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struct host_vm_op *last;
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int fd = -1, ret = 0;
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int fd = -1, ret = 0;
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if (virt + len > STUB_START && virt < STUB_END)
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return -EINVAL;
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if (hvc->userspace)
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if (hvc->userspace)
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fd = phys_mapping(phys, &offset);
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fd = phys_mapping(phys, &offset);
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else
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else
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@ -163,7 +166,7 @@ static int add_munmap(unsigned long addr, unsigned long len,
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struct host_vm_op *last;
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struct host_vm_op *last;
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int ret = 0;
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int ret = 0;
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if ((addr >= STUB_START) && (addr < STUB_END))
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if (addr + len > STUB_START && addr < STUB_END)
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return -EINVAL;
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return -EINVAL;
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if (hvc->index != 0) {
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if (hvc->index != 0) {
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@ -193,6 +196,9 @@ static int add_mprotect(unsigned long addr, unsigned long len,
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struct host_vm_op *last;
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struct host_vm_op *last;
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int ret = 0;
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int ret = 0;
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if (addr + len > STUB_START && addr < STUB_END)
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return -EINVAL;
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if (hvc->index != 0) {
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if (hvc->index != 0) {
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last = &hvc->ops[hvc->index - 1];
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last = &hvc->ops[hvc->index - 1];
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if ((last->type == MPROTECT) &&
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if ((last->type == MPROTECT) &&
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@ -433,6 +439,10 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long address)
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struct mm_id *mm_id;
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struct mm_id *mm_id;
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address &= PAGE_MASK;
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address &= PAGE_MASK;
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if (address >= STUB_START && address < STUB_END)
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goto kill;
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pgd = pgd_offset(mm, address);
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pgd = pgd_offset(mm, address);
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if (!pgd_present(*pgd))
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if (!pgd_present(*pgd))
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goto kill;
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goto kill;
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