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Use alloc_size attribute on *alloc functions

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malloc and family were not declared with __attribute__((alloc_size)).
This was (sometimes) preventing FORTIFY_SOURCE related functions
from knowing the size of the buffer it's dealing with, inhibiting
FORTIFY_SOURCE protections.

Add __attribute__((alloc_size))

Information about the alloc_size attribute can be found
at http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html

Change-Id: Ia2f0a445f0170a7325f69259b5e7fb35a9f14921
This commit is contained in:
Nick Kralevich 2013-10-02 14:14:40 -07:00
parent 4bbf3a8b55
commit b91791d71c
2 changed files with 20 additions and 6 deletions
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12
libc/include/malloc.h
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@ -27,16 +27,16 @@
__BEGIN_DECLS
extern void* malloc(size_t byte_count) __mallocfunc __wur;
extern void* calloc(size_t item_count, size_t item_size) __mallocfunc __wur;
extern void* realloc(void* p, size_t byte_count) __wur;
extern void* malloc(size_t byte_count) __mallocfunc __wur __attribute__((alloc_size(1)));
extern void* calloc(size_t item_count, size_t item_size) __mallocfunc __wur __attribute__((alloc_size(1,2)));
extern void* realloc(void* p, size_t byte_count) __wur __attribute__((alloc_size(2)));
extern void free(void* p);
extern void* memalign(size_t alignment, size_t byte_count) __mallocfunc __wur;
extern void* memalign(size_t alignment, size_t byte_count) __mallocfunc __wur __attribute__((alloc_size(2)));
extern size_t malloc_usable_size(const void* p);
extern void* valloc(size_t byte_count) __mallocfunc __wur;
extern void* pvalloc(size_t byte_count) __mallocfunc __wur;
extern void* valloc(size_t byte_count) __mallocfunc __wur __attribute__((alloc_size(1)));
extern void* pvalloc(size_t byte_count) __mallocfunc __wur __attribute__((alloc_size(1)));
#ifndef STRUCT_MALLINFO_DECLARED
#define STRUCT_MALLINFO_DECLARED 1

14
tests/fortify_test.cpp
View File

@ -20,6 +20,7 @@
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <malloc.h>
// We have to say "DeathTest" here so gtest knows to run this test (which exits)
// in its own process. Unfortunately, the C preprocessor doesn't give us an
@ -395,6 +396,19 @@ TEST(DEATHTEST, sprintf_fortified) {
ASSERT_EXIT(sprintf(buf, "%s", source_buf), testing::KilledBySignal(SIGABRT), "");
}
#ifndef __clang__
// This test is disabled in clang because clang doesn't properly detect
// this buffer overflow. TODO: Fix clang.
TEST(DEATHTEST, sprintf_malloc_fortified) {
::testing::FLAGS_gtest_death_test_style = "threadsafe";
char* buf = (char *) malloc(10);
char source_buf[11];
memcpy(source_buf, "1234567890", 11);
ASSERT_EXIT(sprintf(buf, "%s", source_buf), testing::KilledBySignal(SIGABRT), "");
free(buf);
}
#endif
TEST(DEATHTEST, sprintf2_fortified) {
::testing::FLAGS_gtest_death_test_style = "threadsafe";
char buf[5];