From 64ffbe04eaafebf4045a3ace52a360c14959d196 Mon Sep 17 00:00:00 2001 From: Wolfgang Bumiller Date: Wed, 13 Jan 2016 09:09:58 +0100 Subject: [PATCH] hmp: fix sendkey out of bounds write (CVE-2015-8619) When processing 'sendkey' command, hmp_sendkey routine null terminates the 'keyname_buf' array. This results in an OOB write issue, if 'keyname_len' was to fall outside of 'keyname_buf' array. Since the keyname's length is known the keyname_buf can be removed altogether by adding a length parameter to index_from_key() and using it for the error output as well. Reported-by: Ling Liu Signed-off-by: Wolfgang Bumiller Message-Id: <20160113080958.GA18934@olga> [Comparison with "<" dumbed down, test for junk after strtoul() tweaked] Signed-off-by: Markus Armbruster --- hmp.c | 18 ++++++++---------- include/ui/console.h | 2 +- ui/input-legacy.c | 5 +++-- 3 files changed, 12 insertions(+), 13 deletions(-) diff --git a/hmp.c b/hmp.c index 54f2620..9c571f5 100644 --- a/hmp.c +++ b/hmp.c @@ -1731,21 +1731,18 @@ void hmp_sendkey(Monitor *mon, const QDict *qdict) int has_hold_time = qdict_haskey(qdict, "hold-time"); int hold_time = qdict_get_try_int(qdict, "hold-time", -1); Error *err = NULL; - char keyname_buf[16]; char *separator; int keyname_len; while (1) { separator = strchr(keys, '-'); keyname_len = separator ? separator - keys : strlen(keys); - pstrcpy(keyname_buf, sizeof(keyname_buf), keys); /* Be compatible with old interface, convert user inputted "<" */ - if (!strncmp(keyname_buf, "<", 1) && keyname_len == 1) { - pstrcpy(keyname_buf, sizeof(keyname_buf), "less"); + if (keys[0] == '<' && keyname_len == 1) { + keys = "less"; keyname_len = 4; } - keyname_buf[keyname_len] = 0; keylist = g_malloc0(sizeof(*keylist)); keylist->value = g_malloc0(sizeof(*keylist->value)); @@ -1758,16 +1755,17 @@ void hmp_sendkey(Monitor *mon, const QDict *qdict) } tmp = keylist; - if (strstart(keyname_buf, "0x", NULL)) { + if (strstart(keys, "0x", NULL)) { char *endp; - int value = strtoul(keyname_buf, &endp, 0); - if (*endp != '\0') { + int value = strtoul(keys, &endp, 0); + assert(endp <= keys + keyname_len); + if (endp != keys + keyname_len) { goto err_out; } keylist->value->type = KEY_VALUE_KIND_NUMBER; keylist->value->u.number = value; } else { - int idx = index_from_key(keyname_buf); + int idx = index_from_key(keys, keyname_len); if (idx == Q_KEY_CODE_MAX) { goto err_out; } @@ -1789,7 +1787,7 @@ out: return; err_out: - monitor_printf(mon, "invalid parameter: %s\n", keyname_buf); + monitor_printf(mon, "invalid parameter: %.*s\n", keyname_len, keys); goto out; } diff --git a/include/ui/console.h b/include/ui/console.h index adac36d..116bc2b 100644 --- a/include/ui/console.h +++ b/include/ui/console.h @@ -448,7 +448,7 @@ static inline int vnc_display_pw_expire(const char *id, time_t expires) void curses_display_init(DisplayState *ds, int full_screen); /* input.c */ -int index_from_key(const char *key); +int index_from_key(const char *key, size_t key_length); /* gtk.c */ void early_gtk_display_init(int opengl); diff --git a/ui/input-legacy.c b/ui/input-legacy.c index 35dfc27..3454055 100644 --- a/ui/input-legacy.c +++ b/ui/input-legacy.c @@ -57,12 +57,13 @@ struct QEMUPutLEDEntry { static QTAILQ_HEAD(, QEMUPutLEDEntry) led_handlers = QTAILQ_HEAD_INITIALIZER(led_handlers); -int index_from_key(const char *key) +int index_from_key(const char *key, size_t key_length) { int i; for (i = 0; QKeyCode_lookup[i] != NULL; i++) { - if (!strcmp(key, QKeyCode_lookup[i])) { + if (!strncmp(key, QKeyCode_lookup[i], key_length) && + !QKeyCode_lookup[i][key_length]) { break; } } -- 2.7.4