[PATCH v2 4/4] mm/msync: return ENOMEM if len overflows for msync

From: Wupeng Ma
Date: Mon Jan 16 2023 - 06:59:12 EST


From: Ma Wupeng <mawupeng1@xxxxxxxxxx>

Return -ENOMEM if len overflows for msync.

Signed-off-by: Ma Wupeng <mawupeng1@xxxxxxxxxx>
---
mm/msync.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/msync.c b/mm/msync.c
index ac4c9bfea2e7..8ac227ec38af 100644
--- a/mm/msync.c
+++ b/mm/msync.c
@@ -36,6 +36,7 @@ SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
struct vm_area_struct *vma;
int unmapped_error = 0;
int error = -EINVAL;
+ size_t old_len = len;

start = untagged_addr(start);

@@ -48,7 +49,7 @@ SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
error = -ENOMEM;
len = (len + ~PAGE_MASK) & PAGE_MASK;
end = start + len;
- if (end < start)
+ if (end < start || (old_len != 0 && len == 0))
goto out;
error = 0;
if (end == start)
--
2.25.1