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 2369721..2762674 100644
--- a/include/types/arg.h
+++ b/include/types/arg.h
@@ -63,8 +63,9 @@
};
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 8ec046f..e51dafc 100644
--- a/src/acl.c
+++ b/src/acl.c
@@ -1227,11 +1227,10 @@
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 @@
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 @@
}
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 @@
}
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 @@
}
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 @@
}
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 @@
}
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 457c5b3..9d5fcee 100644
--- a/src/arg.c
+++ b/src/arg.c
@@ -127,6 +127,11 @@
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 ff962c2..48c3433 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -772,11 +772,10 @@
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++;
}