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authorJeroen van Bemmel <jvb127@gmail.com>2012-07-12 11:23:28 +0530
committerSiddhesh Poyarekar <siddhesh@redhat.com>2012-07-12 11:31:48 +0530
commit7b6e99be77c24a79cb07416d81796b45176923c6 (patch)
treeec6fdfbc4df5a1dec8305ff8d9cd75a6e0d0608f /sysdeps
parenta766fb45a3473c416df010d614287012f7a00838 (diff)
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Avoid duplicate DNS requests if answer is longer than a implementation
limit

        [BZ #14307]
        * sysdeps/posix/getaddrinfo.c (gaih_inet): Increase the size of
        the temporary buffer used to invoke __gethostbyname2_r,
        __gethostbyaddr_r and gethostbyname4_r to make room for struct
        host_data / struct gaih_addrtuple.
        * resolv/nss_dns/dns-host.c (global scope): Move definition of
        implementation constants MAX_NR_ALIASES and MAX_NR_ADDRS to
        header file nss/nsswitch.h.
        * nss/nsswitch.h (global scope): Add definition of implementation
        constants MAX_NR_ALIASES and MAX_NR_ADDRS (moved from
        resolv/nss_dns/dns-host.c).
Diffstat (limited to 'sysdeps')
-rw-r--r--sysdeps/posix/getaddrinfo.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/sysdeps/posix/getaddrinfo.c b/sysdeps/posix/getaddrinfo.c
index 2eca2ae0e4..78a2474b10 100644
--- a/sysdeps/posix/getaddrinfo.c
+++ b/sysdeps/posix/getaddrinfo.c
@@ -568,7 +568,9 @@ gaih_inet (const char *name, const struct gaih_service *service,
 	     IPv6 scope ids. */
 	  if (req->ai_family == AF_INET)
 	    {
-	      size_t tmpbuflen = 512;
+	      /* Allocate additional room for struct host_data.  */
+	      size_t tmpbuflen = (512 + MAX_NR_ALIASES * sizeof(char*)
+				  + 16 * sizeof(char));
 	      assert (tmpbuf == NULL);
 	      tmpbuf = alloca_account (tmpbuflen, alloca_used);
 	      int rc;
@@ -811,7 +813,7 @@ gaih_inet (const char *name, const struct gaih_service *service,
 	  old_res_options = _res.options;
 	  _res.options &= ~RES_USE_INET6;
 
-	  size_t tmpbuflen = 1024;
+	  size_t tmpbuflen = 1024 + sizeof(struct gaih_addrtuple);
 	  malloc_tmpbuf = !__libc_use_alloca (alloca_used + tmpbuflen);
 	  assert (tmpbuf == NULL);
 	  if (!malloc_tmpbuf)
@@ -1113,7 +1115,9 @@ gaih_inet (const char *name, const struct gaih_service *service,
 		struct hostent *h = NULL;
 		int herrno;
 		struct hostent th;
-		size_t tmpbuf2len = 512;
+		/* Add room for struct host_data.  */
+		size_t tmpbuf2len = (512 + (MAX_NR_ALIASES+MAX_NR_ADDRS+1)
+				     * sizeof(char*) + 16 * sizeof(char));
 
 		do
 		  {