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| author | Rich Felker <dalias@aerifal.cx> | 2018-04-17 15:18:49 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2018-04-17 19:23:01 -0400 |
| commit | 14032c30e2d41e5c0dac25d399f7086f74d4e0c8 (patch) | |
| tree | 085e4b76575b4fa62077c72e9595d9b44e60d9da | |
| parent | ce7ae11acfd9db8eb92cc6823c132e1825918d92 (diff) | |
| download | musl-14032c30e2d41e5c0dac25d399f7086f74d4e0c8.tar.gz | |
comment __malloc_donate overflow logic
| -rw-r--r-- | src/malloc/malloc.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/src/malloc/malloc.c b/src/malloc/malloc.c index 6605ec3a..991300cc 100644 --- a/src/malloc/malloc.c +++ b/src/malloc/malloc.c @@ -563,6 +563,9 @@ void __malloc_donate(char *start, char *end) size_t align_start_up = (SIZE_ALIGN-1) & (-(uintptr_t)start - OVERHEAD); size_t align_end_down = (SIZE_ALIGN-1) & (uintptr_t)end; + /* Getting past this condition ensures that the padding for alignment + * and header overhead will not overflow and will leave a nonzero + * multiple of SIZE_ALIGN bytes between start and end. */ if (end - start <= OVERHEAD + align_start_up + align_end_down) return; start += align_start_up + OVERHEAD; |