From: Alison Schofield <[email protected]> Memory encryption is only supported for mappings that are ANONYMOUS. Test the VMA's in an encrypt_mprotect() request to make sure they all meet that requirement before encrypting any.
The encrypt_mprotect syscall will return -EINVAL and will not encrypt any VMA's if this check fails. Signed-off-by: Alison Schofield <[email protected]> Signed-off-by: Kirill A. Shutemov <[email protected]> --- mm/mprotect.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/mm/mprotect.c b/mm/mprotect.c index 518d75582e7b..4b079e1b2d6f 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -347,6 +347,24 @@ static int prot_none_walk(struct vm_area_struct *vma, unsigned long start, return walk_page_range(start, end, &prot_none_walk); } +/* + * Encrypted mprotect is only supported on anonymous mappings. + * If this test fails on any single VMA, the entire mprotect + * request fails. + */ +static bool mem_supports_encryption(struct vm_area_struct *vma, unsigned long end) +{ + struct vm_area_struct *test_vma = vma; + + do { + if (!vma_is_anonymous(test_vma)) + return false; + + test_vma = test_vma->vm_next; + } while (test_vma && test_vma->vm_start < end); + return true; +} + int mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, unsigned long start, unsigned long end, unsigned long newflags, @@ -533,6 +551,12 @@ static int do_mprotect_ext(unsigned long start, size_t len, goto out; } } + + if (keyid > 0 && !mem_supports_encryption(vma, end)) { + error = -EINVAL; + goto out; + } + if (start > vma->vm_start) prev = vma; -- 2.21.0
