From 7e13e5ae69a243b90b90d2f4b79b2a150f806335 Mon Sep 17 00:00:00 2001 From: Alexey Izbyshev Date: Thu, 26 Jan 2023 14:47:39 +0300 Subject: [PATCH] inet_pton: fix uninitialized memory use for IPv4-mapped IPv6 addresses When a dot is encountered, the loop counter is incremented before exiting the loop, but the corresponding ip array element is left uninitialized, so the subsequent memmove (if "::" was seen) and the loop copying ip to the output buffer will operate on an uninitialized uint16_t. The uninitialized data never directly influences the control flow and is overwritten on successful return by the second half of the parsed IPv4 address. But it's better to fix this to avoid unexpected transformations by a sufficiently smart compiler and reports from UB-detection tools. --- src/network/inet_pton.c | 1 + 1 file changed, 1 insertion(+) diff --git a/src/network/inet_pton.c b/src/network/inet_pton.c index d36c3689..bcbdd9ef 100644 --- a/src/network/inet_pton.c +++ b/src/network/inet_pton.c @@ -54,6 +54,7 @@ int inet_pton(int af, const char *restrict s, void *restrict a0) if (s[j]!='.' || (i<6 && brk<0)) return 0; need_v4=1; i++; + ip[i&7]=0; break; } s += j+1; -- 2.20.1