On 09/08/2023 12:07, Luca Vizzarro wrote:
Whenever a GUP call is made, a user address in the form of a 64-bit integer is used to lookup its corresponding page. When working in PCuABI, this means that the metadata of the user capability gets discarded, hence any access made by the GUP is not checked in hardware.
This commit introduces explicit capability checks whenever a call to the current mm through the GUP functions is made.
Signed-off-by: Luca Vizzarro Luca.Vizzarro@arm.com
kernel/futex/core.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/kernel/futex/core.c b/kernel/futex/core.c index 4b79b5e2ad3b..ed7837ca245f 100644 --- a/kernel/futex/core.c +++ b/kernel/futex/core.c @@ -226,8 +226,6 @@ int get_futex_key(u32 __user *uaddr, bool fshared, union futex_key *key, struct address_space *mapping; int err, ro = 0;
- /* TODO [PCuABI] - capability checks for uaccess */
That especially calls for some explanation in the commit message.
- /*
*/
- The futex address must be "naturally" aligned.
@@ -413,7 +411,14 @@ int fault_in_user_writeable(u32 __user *uaddr) struct mm_struct *mm = current->mm; int ret;
- /* TODO [PCuABI] - capability checks for uaccess */
- /*
* When working in PCuABI, we may have reached this point because the* atomic load/store failed as a consequence of the capability fault
s/the/a/
Kevin
* and not a page fault. To cover this case we should employ an explicit* check, so that we can fail and return early.*/- if (!check_user_ptr_rw(uaddr, sizeof(u32)))
return -EFAULT;mmap_read_lock(mm); ret = fixup_user_fault(mm, user_ptr_addr(uaddr),