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..
--
2.42.0.609.gbb76f46606-goog