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brcmfmac: backport length check in brcmf_cfg80211_escan_handler()

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Fixes CVE-2017-0786

Signed-off-by: Felix Fietkau <nbd@nbd.name>
This commit is contained in:
Felix Fietkau 2017-10-16 12:46:58 +02:00
parent fa0b5fce1f
commit bff16304b0
1 changed files with 63 additions and 0 deletions
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package/kernel/mac80211/patches/326-brcmfmac-add-length-check-in-brcmf_cfg80211_escan_ha.patch Normal file
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@ -0,0 +1,63 @@
From: Arend Van Spriel <arend.vanspriel@broadcom.com>
Date: Tue, 12 Sep 2017 10:47:53 +0200
Subject: [PATCH] brcmfmac: add length check in brcmf_cfg80211_escan_handler()
Upon handling the firmware notification for scans the length was
checked properly and may result in corrupting kernel heap memory
due to buffer overruns. This fix addresses CVE-2017-0786.
Cc: stable@vger.kernel.org # v4.0.x
Cc: Kevin Cernekee <cernekee@chromium.org>
Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
---
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
@@ -3088,6 +3088,7 @@ brcmf_cfg80211_escan_handler(struct brcm
struct brcmf_cfg80211_info *cfg = ifp->drvr->config;
s32 status;
struct brcmf_escan_result_le *escan_result_le;
+ u32 escan_buflen;
struct brcmf_bss_info_le *bss_info_le;
struct brcmf_bss_info_le *bss = NULL;
u32 bi_length;
@@ -3104,11 +3105,23 @@ brcmf_cfg80211_escan_handler(struct brcm
if (status == BRCMF_E_STATUS_PARTIAL) {
brcmf_dbg(SCAN, "ESCAN Partial result\n");
+ if (e->datalen < sizeof(*escan_result_le)) {
+ brcmf_err("invalid event data length\n");
+ goto exit;
+ }
escan_result_le = (struct brcmf_escan_result_le *) data;
if (!escan_result_le) {
brcmf_err("Invalid escan result (NULL pointer)\n");
goto exit;
}
+ escan_buflen = le32_to_cpu(escan_result_le->buflen);
+ if (escan_buflen > BRCMF_ESCAN_BUF_SIZE ||
+ escan_buflen > e->datalen ||
+ escan_buflen < sizeof(*escan_result_le)) {
+ brcmf_err("Invalid escan buffer length: %d\n",
+ escan_buflen);
+ goto exit;
+ }
if (le16_to_cpu(escan_result_le->bss_count) != 1) {
brcmf_err("Invalid bss_count %d: ignoring\n",
escan_result_le->bss_count);
@@ -3125,9 +3138,8 @@ brcmf_cfg80211_escan_handler(struct brcm
}
bi_length = le32_to_cpu(bss_info_le->length);
- if (bi_length != (le32_to_cpu(escan_result_le->buflen) -
- WL_ESCAN_RESULTS_FIXED_SIZE)) {
- brcmf_err("Invalid bss_info length %d: ignoring\n",
+ if (bi_length != escan_buflen - WL_ESCAN_RESULTS_FIXED_SIZE) {
+ brcmf_err("Ignoring invalid bss_info length: %d\n",
bi_length);
goto exit;
}