[linux-morello] [PATCH RFC 10/19] mm/mlock: Add the PCuABI reservation interfaces

Use the recently introduced PCuABI reservation interfaces to verify the address range for mlock, mlock2 and munlock syscalls.

Signed-off-by: Amit Daniel Kachhap amit.kachhap@arm.com --- mm/mlock.c | 37 +++++++++++++++++++++++++++++++------ 1 file changed, 31 insertions(+), 6 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c index 40b43f8740df..43b6b8a8a0ff 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -25,6 +25,7 @@ #include <linux/memcontrol.h> #include <linux/mm_inline.h> #include <linux/secretmem.h> +#include <linux/cap_addr_mgmt.h>

#include "internal.h"

@@ -563,13 +564,18 @@ static int __mlock_posix_error_return(long retval) return retval; }

-static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t flags) +static __must_check int do_mlock(user_uintptr_t user_start, size_t len, vm_flags_t flags) { unsigned long locked; unsigned long lock_limit; int error = -ENOMEM; + unsigned long start = untagged_addr((ptraddr_t)user_start);

- start = untagged_addr(start); +#ifdef CONFIG_CHERI_PURECAP_UABI + user_start = cheri_address_set(user_start, start); + if (!capability_owns_range(user_start, start, len)) + return -EINVAL; +#endif

if (!can_do_mlock()) return -EPERM; @@ -584,6 +590,13 @@ static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t fla if (mmap_write_lock_killable(current->mm)) return -EINTR;

+#ifdef CONFIG_CHERI_PURECAP_UABI + /* Check if the range exists within the reservation with mmap lock. */ + if (!reserv_mt_capability_bound_valid(&current->mm->reserv_mt, user_start)) { + mmap_write_unlock(current->mm); + return -ERESERVATION; + } +#endif locked += current->mm->locked_vm; if ((locked > lock_limit) && (!capable(CAP_IPC_LOCK))) { /* @@ -610,12 +623,12 @@ static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t fla return 0; }

-SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) +SYSCALL_DEFINE2(mlock, user_uintptr_t, start, size_t, len) { return do_mlock(start, len, VM_LOCKED); }

-SYSCALL_DEFINE3(mlock2, unsigned long, start, size_t, len, int, flags) +SYSCALL_DEFINE3(mlock2, user_uintptr_t, start, size_t, len, int, flags) { vm_flags_t vm_flags = VM_LOCKED;

@@ -628,17 +641,29 @@ SYSCALL_DEFINE3(mlock2, unsigned long, start, size_t, len, int, flags) return do_mlock(start, len, vm_flags); }

-SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) +SYSCALL_DEFINE2(munlock, user_uintptr_t, user_start, size_t, len) { int ret; + unsigned long start = untagged_addr((ptraddr_t)user_start);

- start = untagged_addr(start); +#ifdef CONFIG_CHERI_PURECAP_UABI + user_start = cheri_address_set(user_start, start); + if (!capability_owns_range(user_start, start, len)) + return -EINVAL; +#endif

len = PAGE_ALIGN(len + (offset_in_page(start))); start &= PAGE_MASK;

if (mmap_write_lock_killable(current->mm)) return -EINTR; +#ifdef CONFIG_CHERI_PURECAP_UABI + /* Check if the range exists within the reservation with mmap lock. */ + if (!reserv_mt_capability_bound_valid(&current->mm->reserv_mt, user_start)) { + mmap_write_unlock(current->mm); + return -ERESERVATION; + } +#endif ret = apply_vma_lock_flags(start, len, 0); mmap_write_unlock(current->mm);