[glibc/release/2.41/master] resolv: Check for inet_ntop failure in ns_sprintrrf

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=1c77f57252fd8cfeb30c988a001cd1aab172483b

commit 1c77f57252fd8cfeb30c988a001cd1aab172483b
Author: Florian Weimer <[email protected]>
Date:   Fri Jun 19 18:22:20 2026 +0200

    resolv: Check for inet_ntop failure in ns_sprintrrf
    
    This makes the output more consistent (either failure or complete
    output) and helps with systematic testing with varying buffer
    sizes.
    
    Reviewed-by: Carlos O'Donell <[email protected]>
    Reviewed-by: Adhemerval Zanella <[email protected]>
    (cherry picked from commit cd0db208d56a2cecd528b8ae96df752ba5344d9a)

Diff:
---
 resolv/ns_print.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/resolv/ns_print.c b/resolv/ns_print.c
index 3d38876483..e58df5f35a 100644
--- a/resolv/ns_print.c
+++ b/resolv/ns_print.c
@@ -167,8 +167,9 @@ ns_sprintrrf(const u_char *msg, size_t msglen,
 	switch (type) {
 	case ns_t_a:
 	  if (rdlen != (size_t)NS_INADDRSZ)
-			goto formerr;
-		(void) inet_ntop(AF_INET, rdata, buf, buflen);
+		  goto formerr;
+		if (inet_ntop (AF_INET, rdata, buf, buflen) == NULL)
+		  return -1;
 		addlen(strlen(buf), &buf, &buflen);
 		break;
 
@@ -334,9 +335,10 @@ ns_sprintrrf(const u_char *msg, size_t msglen,
 	    }
 
 	case ns_t_aaaa:
-	  if (rdlen != (size_t)NS_IN6ADDRSZ)
-			goto formerr;
-		(void) inet_ntop(AF_INET6, rdata, buf, buflen);
+		if (rdlen != (size_t)NS_IN6ADDRSZ)
+		  goto formerr;
+		if (inet_ntop (AF_INET6, rdata, buf, buflen) == NULL)
+		  return -1;
 		addlen(strlen(buf), &buf, &buflen);
 		break;
 
@@ -427,7 +429,8 @@ ns_sprintrrf(const u_char *msg, size_t msglen,
 			goto formerr;
 
 		/* Address. */
-		(void) inet_ntop(AF_INET, rdata, buf, buflen);
+		if (inet_ntop (AF_INET, rdata, buf, buflen) == NULL)
+		  return -1;
 		addlen(strlen(buf), &buf, &buflen);
 		rdata += NS_INADDRSZ;
 
@@ -569,7 +572,8 @@ ns_sprintrrf(const u_char *msg, size_t msglen,
 			if (rdata + pbyte >= edata) goto formerr;
 			memset(&a, 0, sizeof(a));
 			memcpy(&a.s6_addr[pbyte], rdata, sizeof(a) - pbyte);
-			(void) inet_ntop(AF_INET6, &a, buf, buflen);
+			if (inet_ntop (AF_INET6, &a, buf, buflen) == NULL)
+			  return -1;
 			addlen(strlen(buf), &buf, &buflen);
 			rdata += sizeof(a) - pbyte;
 		}