From: Avery Pennarun <apenwarr@gmail.com>
Date: Mon, 31 Oct 2011 21:49:55 +0000 (-0400)
Subject: bupsplit.c: remove extra-large stack-allocated array from selftest().
X-Git-Url: https://git.michaelhowe.org/gitweb/?a=commitdiff_plain;h=840f15b66b7b471d28dce56b2159b1dd45f39244;p=packages%2Fb%2Fbup.git

bupsplit.c: remove extra-large stack-allocated array from selftest().

In some rare cases involving userspace threads (where you're running the
selftest function for some reason?) this could cause stack overflow or
excess memory usage.  Let's just do it with plain malloc().

Signed-off-by: Avery Pennarun <apenwarr@gmail.com>
---

diff --git a/lib/bup/bupsplit.c b/lib/bup/bupsplit.c
index f8132a1..067b2e9 100644
--- a/lib/bup/bupsplit.c
+++ b/lib/bup/bupsplit.c
@@ -118,22 +118,23 @@ int bupsplit_find_ofs(const unsigned char *buf, int len, int *bits)
 
 
 #ifndef BUP_NO_SELFTEST
+#define BUP_SELFTEST_SIZE 100000
 
 int bupsplit_selftest()
 {
-    uint8_t buf[100000];
+    uint8_t *buf = malloc(BUP_SELFTEST_SIZE);
     uint32_t sum1a, sum1b, sum2a, sum2b, sum3a, sum3b;
     unsigned count;
     
     srandom(1);
-    for (count = 0; count < sizeof(buf); count++)
+    for (count = 0; count < BUP_SELFTEST_SIZE; count++)
 	buf[count] = random();
     
-    sum1a = rollsum_sum(buf, 0, sizeof(buf));
-    sum1b = rollsum_sum(buf, 1, sizeof(buf));
-    sum2a = rollsum_sum(buf, sizeof(buf) - BUP_WINDOWSIZE*5/2,
-			sizeof(buf) - BUP_WINDOWSIZE);
-    sum2b = rollsum_sum(buf, 0, sizeof(buf) - BUP_WINDOWSIZE);
+    sum1a = rollsum_sum(buf, 0, BUP_SELFTEST_SIZE);
+    sum1b = rollsum_sum(buf, 1, BUP_SELFTEST_SIZE);
+    sum2a = rollsum_sum(buf, BUP_SELFTEST_SIZE - BUP_WINDOWSIZE*5/2,
+			BUP_SELFTEST_SIZE - BUP_WINDOWSIZE);
+    sum2b = rollsum_sum(buf, 0, BUP_SELFTEST_SIZE - BUP_WINDOWSIZE);
     sum3a = rollsum_sum(buf, 0, BUP_WINDOWSIZE+3);
     sum3b = rollsum_sum(buf, 3, BUP_WINDOWSIZE+3);
     
@@ -144,6 +145,7 @@ int bupsplit_selftest()
     fprintf(stderr, "sum3a = 0x%08x\n", sum3a);
     fprintf(stderr, "sum3b = 0x%08x\n", sum3b);
     
+    free(buf);
     return sum1a!=sum1b || sum2a!=sum2b || sum3a!=sum3b;
 }