Check for bad packets in getaddrinfo.c's getanswer.
The near duplicate in gethnamaddr.c was already doing so (this fix
is basically copy and pasted from there, but with both copies modified
to avoid skirting undefined behavior).
Bug: http://b/32322088
Test: browser still works
Change-Id: Ied6662be567fb1bddc7ceb138cae1da77fb57976
diff --git a/libc/dns/net/gethnamaddr.c b/libc/dns/net/gethnamaddr.c
index 42f0d0a..75cb2b3 100644
--- a/libc/dns/net/gethnamaddr.c
+++ b/libc/dns/net/gethnamaddr.c
@@ -186,14 +186,13 @@
#define BOUNDED_INCR(x) \
do { \
+ BOUNDS_CHECK(cp, x); \
cp += (x); \
- if (cp > eom) \
- goto no_recovery; \
} while (/*CONSTCOND*/0)
#define BOUNDS_CHECK(ptr, count) \
do { \
- if ((ptr) + (count) > eom) \
+ if (eom - (ptr) < (count)) \
goto no_recovery; \
} while (/*CONSTCOND*/0)