diff options
Diffstat (limited to 'mm/mprotect.c')
| -rw-r--r-- | mm/mprotect.c | 61 |
1 files changed, 55 insertions, 6 deletions
diff --git a/mm/mprotect.c b/mm/mprotect.c index abd9c8257b2e..7b35ee3894ee 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -23,11 +23,13 @@ #include <linux/mmu_notifier.h> #include <linux/migrate.h> #include <linux/perf_event.h> +#include <linux/pkeys.h> #include <linux/ksm.h> #include <linux/pkeys.h> #include <asm/uaccess.h> #include <asm/pgtable.h> #include <asm/cacheflush.h> +#include <asm/mmu_context.h> #include <asm/tlbflush.h> #include "internal.h" @@ -364,12 +366,6 @@ static int do_mprotect_pkey(unsigned long start, size_t len, const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP); const bool rier = (current->personality & READ_IMPLIES_EXEC) && (prot & PROT_READ); - /* - * A temporary safety check since we are not validating - * the pkey before we introduce the allocation code. - */ - if (pkey != -1) - return -EINVAL; prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP); if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */ @@ -391,6 +387,14 @@ static int do_mprotect_pkey(unsigned long start, size_t len, if (down_write_killable(¤t->mm->mmap_sem)) return -EINTR; + /* + * If userspace did not allocate the pkey, do not let + * them use it here. + */ + error = -EINVAL; + if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey)) + goto out; + vma = find_vma(current->mm, start); error = -ENOMEM; if (!vma) @@ -485,3 +489,48 @@ SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len, { return do_mprotect_pkey(start, len, prot, pkey); } + +SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val) +{ + int pkey; + int ret; + + /* No flags supported yet. */ + if (flags) + return -EINVAL; + /* check for unsupported init values */ + if (init_val & ~PKEY_ACCESS_MASK) + return -EINVAL; + + down_write(¤t->mm->mmap_sem); + pkey = mm_pkey_alloc(current->mm); + + ret = -ENOSPC; + if (pkey == -1) + goto out; + + ret = arch_set_user_pkey_access(current, pkey, init_val); + if (ret) { + mm_pkey_free(current->mm, pkey); + goto out; + } + ret = pkey; +out: + up_write(¤t->mm->mmap_sem); + return ret; +} + +SYSCALL_DEFINE1(pkey_free, int, pkey) +{ + int ret; + + down_write(¤t->mm->mmap_sem); + ret = mm_pkey_free(current->mm, pkey); + up_write(¤t->mm->mmap_sem); + + /* + * We could provie warnings or errors if any VMA still + * has the pkey set here. + */ + return ret; +} |