From: Jeff Xu jeffxu@google.com
check seal for mremap(2)
Signed-off-by: Jeff Xu jeffxu@google.com --- mm/mremap.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/mm/mremap.c b/mm/mremap.c index e43f9ceaa29d..2288f9d0b126 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -836,7 +836,15 @@ static unsigned long mremap_to(unsigned long addr, unsigned long old_len, if ((mm->map_count + 2) >= sysctl_max_map_count - 3) return -ENOMEM;
+ if (!can_modify_mm(mm, addr, addr + old_len, MM_ACTION_MREMAP, + ON_BEHALF_OF_USERSPACE)) + return -EACCES; + if (flags & MREMAP_FIXED) { + if (!can_modify_mm(mm, new_addr, new_addr + new_len, + MM_ACTION_MREMAP, ON_BEHALF_OF_USERSPACE)) + return -EACCES; + ret = do_munmap(mm, new_addr, new_len, uf_unmap_early); if (ret) goto out; @@ -995,6 +1003,12 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, goto out; }
+ if (!can_modify_mm(mm, addr, addr + old_len, MM_ACTION_MREMAP, + ON_BEHALF_OF_USERSPACE)) { + ret = -EACCES; + goto out; + } + /* * Always allow a shrinking remap: that just unmaps * the unnecessary pages..