From: Willy Tarreau <w@1wt.eu>
Date: Fri, 1 Jun 2012 08:38:29 +0000 (+0200)
Subject: BUG/MEDIUM: ensure that unresolved arguments are freed exactly once
X-Git-Tag: v1.5-dev12~155
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=496aa0111ee22d0deb8ca0c30c85503011219f05;p=thirdparty%2Fhaproxy.git

BUG/MEDIUM: ensure that unresolved arguments are freed exactly once

When passing arguments to ACLs and samples, some types are stored as
strings then resolved later after config parsing is done. Upon exit,
the arguments need to be freed only if the string was not resolved
yet. At the moment we can encounter double free during deinit()
because some arguments (eg: userlists) are freed once as their own
type and once as a string.

The solution consists in adding an "unresolved" flag to the args to
say whether the value is still held in the <str> part or is final.

This could be debugged thanks to a useful bug report from Sander Klein.
---

diff --git a/include/types/arg.h b/include/types/arg.h
index 2369721484..2762674ee1 100644
--- a/include/types/arg.h
+++ b/include/types/arg.h
@@ -63,8 +63,9 @@ union arg_data {
 };
 
 struct arg {
-	int type;              /* argument type */
-	union arg_data data;   /* argument data */
+	unsigned char type;       /* argument type, ARGT_* */
+	unsigned char unresolved; /* argument contains a string in <str> that must be resolved and freed */
+	union arg_data data;      /* argument data */
 };
 
 
diff --git a/src/acl.c b/src/acl.c
index 8ec046ff02..e51dafc9de 100644
--- a/src/acl.c
+++ b/src/acl.c
@@ -1227,11 +1227,10 @@ static struct acl_expr *prune_acl_expr(struct acl_expr *expr)
 	for (arg = expr->args; arg; arg++) {
 		if (arg->type == ARGT_STOP)
 			break;
-		if (arg->type == ARGT_FE || arg->type == ARGT_BE ||
-		    arg->type == ARGT_TAB || arg->type == ARGT_SRV ||
-		    arg->type == ARGT_USR || arg->type == ARGT_STR) {
+		if (arg->type == ARGT_STR || arg->unresolved) {
 			free(arg->data.str.str);
 			arg->data.str.str = NULL;
+			arg->unresolved = 0;
 		}
 		arg++;
 	}
@@ -2065,6 +2064,8 @@ acl_find_targets(struct proxy *p)
 			for (arg = expr->args; arg; arg++) {
 				if (arg->type == ARGT_STOP)
 					break;
+				else if (!arg->unresolved)
+					continue;
 				else if (arg->type == ARGT_SRV) {
 					struct proxy *px;
 					struct server *srv;
@@ -2107,6 +2108,8 @@ acl_find_targets(struct proxy *p)
 					}
 
 					free(expr->args->data.str.str);
+					expr->args->data.str.str = NULL;
+					arg->unresolved = 0;
 					expr->args->data.srv = srv;
 				}
 				else if (arg->type == ARGT_FE) {
@@ -2133,6 +2136,8 @@ acl_find_targets(struct proxy *p)
 					}
 
 					free(expr->args->data.str.str);
+					expr->args->data.str.str = NULL;
+					arg->unresolved = 0;
 					expr->args->data.prx = prx;
 				}
 				else if (arg->type == ARGT_BE) {
@@ -2159,6 +2164,8 @@ acl_find_targets(struct proxy *p)
 					}
 
 					free(expr->args->data.str.str);
+					expr->args->data.str.str = NULL;
+					arg->unresolved = 0;
 					expr->args->data.prx = prx;
 				}
 				else if (arg->type == ARGT_TAB) {
@@ -2186,6 +2193,8 @@ acl_find_targets(struct proxy *p)
 					}
 
 					free(expr->args->data.str.str);
+					expr->args->data.str.str = NULL;
+					arg->unresolved = 0;
 					expr->args->data.prx = prx;
 				}
 				else if (arg->type == ARGT_USR) {
@@ -2210,6 +2219,8 @@ acl_find_targets(struct proxy *p)
 					}
 
 					free(expr->args->data.str.str);
+					expr->args->data.str.str = NULL;
+					arg->unresolved = 0;
 					expr->args->data.usr = ul;
 				}
 			} /* end of args processing */
diff --git a/src/arg.c b/src/arg.c
index 457c5b38da..9d5fceec2d 100644
--- a/src/arg.c
+++ b/src/arg.c
@@ -127,6 +127,11 @@ int make_arg_list(const char *in, int len, unsigned int mask, struct arg **argp,
 		case ARGT_TAB:
 		case ARGT_SRV:
 		case ARGT_USR:
+			/* These argument types need to be stored as strings during
+			 * parsing then resolved later.
+			 */
+			arg->unresolved = 1;
+			/* fall through */
 		case ARGT_STR:
 			/* all types that must be resolved are stored as strings
 			 * during the parsing. The caller must at one point resolve
diff --git a/src/haproxy.c b/src/haproxy.c
index ff962c2748..48c343344a 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -772,11 +772,10 @@ static void deinit_sample_arg(struct arg *p)
 		return;
 
 	while (p->type != ARGT_STOP) {
-		if (p->type == ARGT_FE || p->type == ARGT_BE ||
-		    p->type == ARGT_TAB || p->type == ARGT_SRV ||
-		    p->type == ARGT_USR || p->type == ARGT_STR) {
+		if (p->type == ARGT_STR || p->unresolved) {
 			free(p->data.str.str);
 			p->data.str.str = NULL;
+			p->unresolved = 0;
 		}
 		p++;
 	}