Skip to content

harden mod_lbmethod_heartbeat parsing and overflow handling #629

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
metsw24-max wants to merge 1 commit into
base: trunk
Choose a base branch
from
+58 −7
Open

harden mod_lbmethod_heartbeat parsing and overflow handling #629

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
65 changes: 58 additions & 7 deletions modules/proxy/balancers/mod_lbmethod_heartbeat.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,9 @@
#include "ap_slotmem.h"
#include "heartbeat.h"

#include <errno.h>
#include <limits.h>

#ifndef LBM_HEARTBEAT_MAX_LASTSEEN
/* If we haven't seen a heartbeat in the last N seconds, don't count this IP
* as allive.
Expand Down Expand Up @@ -61,6 +64,28 @@ typedef struct ctx_servers {
apr_hash_t *servers;
} ctx_servers_t;

static int hb_parse_int(const char *val, int min, int max, int *result)
{
apr_int64_t parsed;
char *end = NULL;

if (!val || !*val) {
return 0;
}

errno = 0;
parsed = apr_strtoi64(val, &end, 10);
if (errno == ERANGE || end == val || *end != '\0') {
return 0;
}
if (parsed < min || parsed > max) {
return 0;
}

*result = (int)parsed;
return 1;
}

static void
argstr_to_table(apr_pool_t *p, char *str, apr_table_t *parms)
{
Expand Down Expand Up @@ -179,19 +204,31 @@ static apr_status_t readfile_heartbeats(const char *path, apr_hash_t *servers,
argstr_to_table(pool, apr_pstrdup(pool, t), hbt);

if ((val = apr_table_get(hbt, "busy"))) {
server->busy = atoi(val);
int parsed;
if (hb_parse_int(val, 0, INT_MAX, &parsed)) {
server->busy = parsed;
}
}

if ((val = apr_table_get(hbt, "ready"))) {
server->ready = atoi(val);
int parsed;
if (hb_parse_int(val, 0, INT_MAX, &parsed)) {
server->ready = parsed;
}
}

if ((val = apr_table_get(hbt, "lastseen"))) {
server->seen = atoi(val);
int parsed;
if (hb_parse_int(val, 0, INT_MAX, &parsed)) {
server->seen = parsed;
}
}

if ((val = apr_table_get(hbt, "port"))) {
server->port = atoi(val);
int parsed;
if (hb_parse_int(val, 1, 65535, &parsed)) {
server->port = parsed;
}
}

if (server->busy == 0 && server->ready != 0) {
Expand Down Expand Up @@ -312,7 +349,13 @@ static proxy_worker *find_best_hb(proxy_balancer *balancer,
if (PROXY_WORKER_IS_USABLE(*worker)) {
server->worker = *worker;
if (server->seen < LBM_HEARTBEAT_MAX_LASTSEEN) {
openslots += server->ready;
apr_uint32_t ready = (apr_uint32_t)server->ready;
if (ready > APR_UINT32_MAX - openslots) {
openslots = APR_UINT32_MAX;
}
else {
openslots += ready;
}
APR_ARRAY_PUSH(up_servers, hb_server_t *) = server;
}
}
Expand All @@ -325,12 +368,20 @@ static proxy_worker *find_best_hb(proxy_balancer *balancer,
pick = ap_random_pick(0, openslots);

for (i = 0; i < up_servers->nelts; i++) {
apr_uint32_t upper;
server = APR_ARRAY_IDX(up_servers, i, hb_server_t *);
if (pick >= c && pick <= c + server->ready) {
if ((apr_uint32_t)server->ready > APR_UINT32_MAX - c) {
upper = APR_UINT32_MAX;
}
else {
upper = c + (apr_uint32_t)server->ready;
}

if (pick >= c && pick <= upper) {
mycandidate = server->worker;
}

c += server->ready;
c = upper;
}
}

Expand Down