DivestOS/Patches/LineageOS-17.1/android_bionic/0003-Graphene_Bionic_Hardening-5.patch
Tad 1df7c7f1d4 Churn
Signed-off-by: Tad <tad@spotco.us>
2022-03-15 19:16:19 -04:00

47 lines
1.7 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Daniel Micay <danielmicay@gmail.com>
Date: Sat, 19 Nov 2016 09:56:14 -0500
Subject: [PATCH] stop implicitly marking mappings as mergeable
---
libc/bionic/mmap.cpp | 19 +------------------
1 file changed, 1 insertion(+), 18 deletions(-)
diff --git a/libc/bionic/mmap.cpp b/libc/bionic/mmap.cpp
index 35033199a..c08106892 100644
--- a/libc/bionic/mmap.cpp
+++ b/libc/bionic/mmap.cpp
@@ -39,8 +39,6 @@ extern "C" void* __mmap2(void*, size_t, int, int, int, size_t);
#define MMAP2_SHIFT 12 // 2**12 == 4096
-static bool kernel_has_MADV_MERGEABLE = true;
-
void* mmap64(void* addr, size_t size, int prot, int flags, int fd, off64_t offset) {
if (offset < 0 || (offset & ((1UL << MMAP2_SHIFT)-1)) != 0) {
errno = EINVAL;
@@ -54,22 +52,7 @@ void* mmap64(void* addr, size_t size, int prot, int flags, int fd, off64_t offse
return MAP_FAILED;
}
- bool is_private_anonymous =
- (flags & (MAP_PRIVATE | MAP_ANONYMOUS)) == (MAP_PRIVATE | MAP_ANONYMOUS);
- bool is_stack_or_grows_down = (flags & (MAP_STACK | MAP_GROWSDOWN)) != 0;
-
- void* result = __mmap2(addr, size, prot, flags, fd, offset >> MMAP2_SHIFT);
-
- if (result != MAP_FAILED && kernel_has_MADV_MERGEABLE &&
- is_private_anonymous && !is_stack_or_grows_down) {
- ErrnoRestorer errno_restorer;
- int rc = madvise(result, size, MADV_MERGEABLE);
- if (rc == -1 && errno == EINVAL) {
- kernel_has_MADV_MERGEABLE = false;
- }
- }
-
- return result;
+ return __mmap2(addr, size, prot, flags, fd, offset >> MMAP2_SHIFT);
}
void* mmap(void* addr, size_t size, int prot, int flags, int fd, off_t offset) {