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authorRich Felker <dalias@aerifal.cx>2011-03-23 13:24:00 -0400
committerRich Felker <dalias@aerifal.cx>2011-03-23 13:24:00 -0400
commit095820016689dfdc9141f477a86de22054c86078 (patch)
tree23543ebec48463f5481441beb8c549b7456b3c1e /src/malloc
parentaa398f56fa398f2202b04e82c67f822f3233786f (diff)
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very cheap double-free checks in malloc
Diffstat (limited to 'src/malloc')
-rw-r--r--src/malloc/malloc.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/src/malloc/malloc.c b/src/malloc/malloc.c
index 3c08c41e..a4eefda9 100644
--- a/src/malloc/malloc.c
+++ b/src/malloc/malloc.c
@@ -393,6 +393,8 @@ void *realloc(void *p, size_t n)
 		char *base = (char *)self - extra;
 		size_t oldlen = n0 + extra;
 		size_t newlen = n + extra;
+		/* Crash on realloc of freed chunk */
+		if ((uintptr_t)base < mal.brk) *(char *)0=0;
 		if (newlen < PAGE_SIZE && (new = malloc(n))) {
 			memcpy(new, p, n-OVERHEAD);
 			free(p);
@@ -454,6 +456,8 @@ void free(void *p)
 		size_t extra = self->data[-1];
 		char *base = (char *)self - extra;
 		size_t len = CHUNK_SIZE(self) + extra;
+		/* Crash on double free */
+		if ((uintptr_t)base < mal.brk) *(char *)0=0;
 		__munmap(base, len);
 		return;
 	}