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authordavidxu <davidxu@FreeBSD.org>2014-02-27 02:36:09 +0000
committerdavidxu <davidxu@FreeBSD.org>2014-02-27 02:36:09 +0000
commit3c6681dc2c610038f536ad483a501e35a1a7312c (patch)
tree27c811097b1e1ebd1b76dac8f1a7de7be6e7aa26 /libexec
parent7f44971ec587a3cd596e85ca429d5242a154cb46 (diff)
downloadFreeBSD-src-3c6681dc2c610038f536ad483a501e35a1a7312c.zip
FreeBSD-src-3c6681dc2c610038f536ad483a501e35a1a7312c.tar.gz
MFC r262277:
malloc_aligned() may not leave enough space for pointer to allocated memory, saving the pointer will overwrite bytes belongs to another memory block unexpectly, to fix the problem, use (allocated address + sizeof(void *)) as initial value, and slip to next aligned address, so maximum extra bytes is sizeof(void *) + align - 1. Tested by: Andre Albsmeier < mail at ma17 dot ata dot myota dot orgndre > MFC r262334: Increase alignment to size of pointer if the alignment is too small. Some modules do not align data at least to size of pointer, they uses a smaller alignment, but our pointer should be aligned to its native boundary, otherwise on some platforms, hardware alignment checking will cause bus error.
Diffstat (limited to 'libexec')
-rw-r--r--libexec/rtld-elf/xmalloc.c12
1 files changed, 5 insertions, 7 deletions
diff --git a/libexec/rtld-elf/xmalloc.c b/libexec/rtld-elf/xmalloc.c
index 3b3408c..ed195df 100644
--- a/libexec/rtld-elf/xmalloc.c
+++ b/libexec/rtld-elf/xmalloc.c
@@ -72,14 +72,12 @@ void *
malloc_aligned(size_t size, size_t align)
{
void *mem, *res;
- uintptr_t x;
- size_t asize, r;
- r = round(sizeof(void *), align);
- asize = round(size, align) + r;
- mem = xmalloc(asize);
- x = (uintptr_t)mem;
- res = (void *)round(x, align);
+ if (align < sizeof(void *))
+ align = sizeof(void *);
+
+ mem = xmalloc(size + sizeof(void *) + align - 1);
+ res = (void *)round((uintptr_t)mem + sizeof(void *), align);
*(void **)((uintptr_t)res - sizeof(void *)) = mem;
return (res);
}
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