181519cf38
11b3a0c2c5db115412c37195#explicit zero 1131456ac632#brk 1158ebc243ea#random 115323b39f7e#undefined 116a91d9dddb#merge 11a042b5a0ba#vla formatting 119ec639de1b#pthread 1149571a0a49#read only 11149cc5ccb8#zero 112e613ccbe7#fork mmap 11e239c7dff8#memprot pthread 110b03d92b7f#xor 11de08419b82#junk 11897d4903e2#guard 11648cd68ca3#ptrhread guard 110bc4dbcbd2#stack rand 10aa9cc05d0710a8cdbb6352#explicit zero 10b28302c668#brk 109f8be7d07c#random 10cb91a7ee3a#undefined 1008279e2fdd#merge 106a18bd565d#vla formatting 102f392c2d08#pthread 108bbce1bc50#read only 10725f61db82#zero 104cd257135f#fork mmap 109220cf622b#memprot pthread 108ef71d1ffd#memprot exit 100eaef1abbd#xor 1064f1cc2148#junk 105c42a527cf#guard 105cc8c34e60#pthread guard 107f61cc8a1c#stack rand 9abdf523d269e4b9b31e6f#explicit zero 9a3a22a63d2#brk 97444dbc3cf#random 9dcd3b72ac9#undefined 9543e1df342#merge 9611e5691f7#vla formatting 98de97ce864#pthread 9a475717042#read only 97f0947cc0e#zero 9e9751d3370#fork mmap 983cd86d0d5#memprot pthread 91ebb165455#memprot exit 9488ba483cf#xor 9f9351d884b#junk 985e5bca0a5#move Signed-off-by: Tad <tad@spotco.us>
77 lines
2.2 KiB
Diff
77 lines
2.2 KiB
Diff
From 31456ac632903235e14500af8b5d7dff2d25d724 Mon Sep 17 00:00:00 2001
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From: Daniel Micay <danielmicay@gmail.com>
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Date: Sun, 8 Feb 2015 01:18:54 -0500
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Subject: [PATCH] replace brk and sbrk with stubs
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Pretend that there is never room to grow the heap in order to prevent
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usage of these unsafe legacy functions. There are likely no users of
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these in practice as it is inherently broken to use them outside of
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malloc.
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Signed-off-by: anupritaisno1 <www.anuprita804@gmail.com>
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---
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libc/bionic/brk.cpp | 48 ++++++++-------------------------------------
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1 file changed, 8 insertions(+), 40 deletions(-)
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diff --git a/libc/bionic/brk.cpp b/libc/bionic/brk.cpp
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index 566c33a7a6..ef93055139 100644
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--- a/libc/bionic/brk.cpp
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+++ b/libc/bionic/brk.cpp
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@@ -29,48 +29,16 @@
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#include <errno.h>
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#include <unistd.h>
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-#if defined(__LP64__)
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-static void* __bionic_brk;
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-#else
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-void* __bionic_brk; // Accidentally exported by the NDK.
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+#if !defined(__LP64__)
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+void* __bionic_brk = reinterpret_cast<void*>(-1); // Accidentally exported by the NDK.
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#endif
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-extern "C" void* __brk(void* __addr);
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-
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-int brk(void* end_data) {
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- __bionic_brk = __brk(end_data);
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- if (__bionic_brk < end_data) {
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- errno = ENOMEM;
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- return -1;
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- }
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- return 0;
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+int brk(void*) {
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+ errno = ENOMEM;
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+ return -1;
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}
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-void* sbrk(ptrdiff_t increment) {
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- // Initialize __bionic_brk if necessary.
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- if (__bionic_brk == nullptr) {
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- __bionic_brk = __brk(nullptr);
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- }
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-
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- // Don't ask the kernel if we already know the answer.
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- if (increment == 0) {
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- return __bionic_brk;
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- }
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-
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- // Avoid overflow.
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- uintptr_t old_brk = reinterpret_cast<uintptr_t>(__bionic_brk);
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- if ((increment > 0 && static_cast<uintptr_t>(increment) > (UINTPTR_MAX - old_brk)) ||
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- (increment < 0 && static_cast<uintptr_t>(-increment) > old_brk)) {
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- errno = ENOMEM;
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- return reinterpret_cast<void*>(-1);
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- }
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-
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- void* desired_brk = reinterpret_cast<void*>(old_brk + increment);
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- __bionic_brk = __brk(desired_brk);
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- if (__bionic_brk < desired_brk) {
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- errno = ENOMEM;
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- return reinterpret_cast<void*>(-1);
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- }
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-
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- return reinterpret_cast<void*>(old_brk);
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+void* sbrk(ptrdiff_t) {
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+ errno = ENOMEM;
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+ return reinterpret_cast<void*>(-1);
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}
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