mwifiex: Fix possible buffer overflows at parsing bss descriptor (CVE-2019-3846)

debian/changelog

@@ -8,6 +8,8 @@ linux (4.19.37-4) UNRELEASED; urgency=medium
     - libbpf: Build out-of-tree
   * README.source: Document the various makefiles and use of out-of-tree builds
   * [x86] lockdown,sysrq: Enable ALLOW_LOCKDOWN_LIFT_BY_SYSRQ (Closes: #929583)
+  * mwifiex: Fix possible buffer overflows at parsing bss descriptor
+    (CVE-2019-3846)
 
   [ Romain Perier ]
   * [rt] Update to 4.19.37-rt20

debian/patches/bugfix/all/mwifiex-fix-possible-buffer-overflows-at-parsing-bss.patch

@@ -0,0 +1,44 @@
+From: Takashi Iwai <tiwai@suse.de>
+Date: Wed, 29 May 2019 14:52:19 +0200
+Subject: mwifiex: Fix possible buffer overflows at parsing bss descriptor
+Origin: https://git.kernel.org/pub/scm/linux/kernel/git/kvalo/wireless-drivers.git/commit?id=13ec7f10b87f5fc04c4ccbd491c94c7980236a74
+Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2019-3846
+
+mwifiex_update_bss_desc_with_ie() calls memcpy() unconditionally in
+a couple places without checking the destination size.  Since the
+source is given from user-space, this may trigger a heap buffer
+overflow.
+
+Fix it by putting the length check before performing memcpy().
+
+This fix addresses CVE-2019-3846.
+
+Reported-by: huangwen <huangwen@venustech.com.cn>
+Signed-off-by: Takashi Iwai <tiwai@suse.de>
+Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
+---
+ drivers/net/wireless/marvell/mwifiex/scan.c | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c
+index 935778ec9a1b..64ab6fe78c0d 100644
+--- a/drivers/net/wireless/marvell/mwifiex/scan.c
++++ b/drivers/net/wireless/marvell/mwifiex/scan.c
+@@ -1247,6 +1247,8 @@ int mwifiex_update_bss_desc_with_ie(struct mwifiex_adapter *adapter,
+ 		}
+ 		switch (element_id) {
+ 		case WLAN_EID_SSID:
++			if (element_len > IEEE80211_MAX_SSID_LEN)
++				return -EINVAL;
+ 			bss_entry->ssid.ssid_len = element_len;
+ 			memcpy(bss_entry->ssid.ssid, (current_ptr + 2),
+ 			       element_len);
+@@ -1256,6 +1258,8 @@ int mwifiex_update_bss_desc_with_ie(struct mwifiex_adapter *adapter,
+ 			break;
+ 
+ 		case WLAN_EID_SUPP_RATES:
++			if (element_len > MWIFIEX_SUPPORTED_RATES)
++				return -EINVAL;
+ 			memcpy(bss_entry->data_rates, current_ptr + 2,
+ 			       element_len);
+ 			memcpy(bss_entry->supported_rates, current_ptr + 2,

debian/patches/series

@@ -217,6 +217,7 @@ bugfix/all/brcmfmac-assure-SSID-length-from-firmware-is-limited.patch
 bugfix/all/brcmfmac-add-subtype-check-for-event-handling-in-dat.patch
 bugfix/all/ext4-zero-out-the-unused-memory-region-in-the-extent.patch
 bugfix/all/Bluetooth-hidp-fix-buffer-overflow.patch
+bugfix/all/mwifiex-fix-possible-buffer-overflows-at-parsing-bss.patch
 
 # Fix exported symbol versions
 bugfix/all/module-disable-matching-missing-version-crc.patch