fixes for enhanced coredump

[Alfred Perlstein]

I was recently working on the enhanced coredumps
internal to Juniper and realized that there were
some defects in the code I pushed (mostly due to
mismerge), can someone please review?

1) don't allocate hostname[] on the stack 
2) don't leak the temp buffer in imgact_elf_coredump.

thank you,
-Alfred


Index: kern/kern_sig.c
===================================================================
--- kern/kern_sig.c	(revision 207329)
+++ kern/kern_sig.c	(working copy)
@@ -3004,8 +3004,9 @@
 	char *temp;
 	size_t i;
 	int indexpos;
-	char hostname[MAXHOSTNAMELEN];
+	char *hostname;
 	
+	hostname = NULL;
 	format = corefilename;
 	temp = malloc(MAXPATHLEN, M_TEMP, M_NOWAIT | M_ZERO);
 	if (temp == NULL)
@@ -3021,6 +3022,19 @@
 				sbuf_putc(&sb, '%');
 				break;
 			case 'H':	/* hostname */
+				if (hostname == NULL) {
+					hostname = malloc(MAXHOSTNAMELEN,
+					    M_TEMP, M_NOWAIT);
+					if (hostname == NULL) {
+						log(LOG_ERR,
+						    "pid %ld (%s), uid (%lu): "
+						    "unable to alloc memory "
+						    "for corefile hostname\n",
+						    (long)pid, name,
+						    (u_long)uid);
+                                                goto nomem;
+                                        }
+                                }
 				getcredhostname(td->td_ucred, hostname,
 				    sizeof(hostname));
 				sbuf_printf(&sb, "%s", hostname);
@@ -3054,9 +3068,10 @@
 	}
 #endif
 	if (sbuf_overflowed(&sb)) {
-		sbuf_delete(&sb);
 		log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too "
 		    "long\n", (long)pid, name, (u_long)uid);
+nomem:
+		sbuf_delete(&sb);
 		free(temp, M_TEMP);
 		return (NULL);
 	}
Index: kern/imgact_elf.c
===================================================================
--- kern/imgact_elf.c	(revision 207329)
+++ kern/imgact_elf.c	(working copy)
@@ -1088,8 +1088,10 @@
 	hdrsize = 0;
 	__elfN(puthdr)(td, (void *)NULL, &hdrsize, seginfo.count);
 
-	if (hdrsize + seginfo.size >= limit)
-		return (EFAULT);
+	if (hdrsize + seginfo.size >= limit) {
+		error = EFAULT;
+		goto done;
+	}
 
 	/*
 	 * Allocate memory for building the header, fill it up,
@@ -1097,7 +1099,8 @@
 	 */
 	hdr = malloc(hdrsize, M_TEMP, M_WAITOK);
 	if (hdr == NULL) {
-		return (EINVAL);
+		error = EINVAL;
+		goto done;
 	}
 	error = __elfN(corehdr)(td, vp, cred, seginfo.count, hdr, hdrsize,
 	    gzfile);
@@ -1125,8 +1128,8 @@
 		    curproc->p_comm, error);
 	}
 
+done:
 #ifdef COMPRESS_USER_CORES
-done:
 	if (core_buf)
 		free(core_buf, M_TEMP);
 	if (gzfile)
-- 
- Alfred Perlstein
.- AMA, VMOA #5191, 03 vmax, 92 gs500, 85 ch250, 07 zx10
.- FreeBSD committer