diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2023-04-03 14:10:20 +0300 |
|---|---|---|
| committer | Dave Hansen <dave.hansen@linux.intel.com> | 2023-04-06 13:45:06 -0700 |
| commit | 97740266de26e5dfe6e4fbecacb6995b66c2e378 (patch) | |
| tree | c57cf73b3ee45b7874d93def94f1fed909d6da92 | |
| parent | fca1fdd2b0a6fcd491ec520afac80bc72b4c811e (diff) | |
x86/mm/iommu/sva: Do not allow to set FORCE_TAGGED_SVA bit from outside
arch_prctl(ARCH_FORCE_TAGGED_SVA) overrides the default and allows LAM
and SVA to co-exist in the process. It is expected by called by the
process when it knows what it is doing.
arch_prctl() operates on the current process, but the same code is
reachable from ptrace where it can be called on arbitrary task.
Make it strict and only allow to set MM_CONTEXT_FORCE_TAGGED_SVA for the
current process.
Fixes: 23e5d9ec2bab ("x86/mm/iommu/sva: Make LAM and SVA mutually exclusive")
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Link: https://lore.kernel.org/all/20230403111020.3136-3-kirill.shutemov%40linux.intel.com
| -rw-r--r-- | arch/x86/kernel/process_64.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index bc2ac5652f88..223b223f713f 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -883,6 +883,8 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2) case ARCH_ENABLE_TAGGED_ADDR: return prctl_enable_tagged_addr(task->mm, arg2); case ARCH_FORCE_TAGGED_SVA: + if (current != task) + return -EINVAL; set_bit(MM_CONTEXT_FORCE_TAGGED_SVA, &task->mm->context.flags); return 0; case ARCH_GET_MAX_TAG_BITS: |