diff options
| author | Thomas Hellstrom <thellstrom@vmware.com> | 2020-03-04 12:45:26 +0100 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-03-17 11:48:31 +0100 |
| commit | 6db73f17c5f155dbcfd5e48e621c706270b84df0 (patch) | |
| tree | 934dd7d64e9164d0e30edbd6bd31963b5232ed70 | |
| parent | x86/mm/kmmio: Use this_cpu_ptr() instead get_cpu_var() for kmmio_ctx (diff) | |
| download | linux-6db73f17c5f155dbcfd5e48e621c706270b84df0.tar.xz linux-6db73f17c5f155dbcfd5e48e621c706270b84df0.zip | |
x86: Don't let pgprot_modify() change the page encryption bit
When SEV or SME is enabled and active, vm_get_page_prot() typically
returns with the encryption bit set. This means that users of
pgprot_modify(, vm_get_page_prot()) (mprotect_fixup(), do_mmap()) end up
with a value of vma->vm_pg_prot that is not consistent with the intended
protection of the PTEs.
This is also important for fault handlers that rely on the VMA
vm_page_prot to set the page protection. Fix this by not allowing
pgprot_modify() to change the encryption bit, similar to how it's done
for PAT bits.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lkml.kernel.org/r/20200304114527.3636-2-thomas_os@shipmail.org
| -rw-r--r-- | arch/x86/include/asm/pgtable.h | 7 | ||||
| -rw-r--r-- | arch/x86/include/asm/pgtable_types.h | 2 |
2 files changed, 6 insertions, 3 deletions
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 7e118660bbd9..64a03f226ab7 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -627,12 +627,15 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) return __pmd(val); } -/* mprotect needs to preserve PAT bits when updating vm_page_prot */ +/* + * mprotect needs to preserve PAT and encryption bits when updating + * vm_page_prot + */ #define pgprot_modify pgprot_modify static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot) { pgprotval_t preservebits = pgprot_val(oldprot) & _PAGE_CHG_MASK; - pgprotval_t addbits = pgprot_val(newprot); + pgprotval_t addbits = pgprot_val(newprot) & ~_PAGE_CHG_MASK; return __pgprot(preservebits | addbits); } diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 0239998d8cdc..65c2ecd730c5 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -118,7 +118,7 @@ */ #define _PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \ _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY | \ - _PAGE_SOFT_DIRTY | _PAGE_DEVMAP) + _PAGE_SOFT_DIRTY | _PAGE_DEVMAP | _PAGE_ENC) #define _HPAGE_CHG_MASK (_PAGE_CHG_MASK | _PAGE_PSE) /* |