MEDIUM: pools: detect() when munmap() fails in UAF mode

Better check that munmap() always works, otherwise it means we might
have miscalculated an address, and if it fails silently, it will eat
all the memory extremely quickly. Let's add a BUG_ON() on munmap's
return.

diff --git a/include/haproxy/pool-os.h b/include/haproxy/pool-os.h
index 016070822c3245fbd9a59cbdab026b8cf3b2bdf3..59bb41b944677d6822302b4e2e8aeaea1948739b 100644 (file)
--- a/include/haproxy/pool-os.h
+++ b/include/haproxy/pool-os.h
@@ -97,7 +97,8 @@ static inline void pool_free_area_uaf(void *area, size_t size)
        if (pad >= sizeof(void *) && *(void **)(area - sizeof(void *)) != area)
                ABORT_NOW();
 
-       munmap(area - pad, (size + 4095) & -4096);
+       /* better know immediately if an address calculation was wrong! */
+       BUG_ON(munmap(area - pad, (size + 4095) & -4096) == -1);
 }
 
 #endif /* _HAPROXY_POOL_OS_H */