git.librecmc.org Git - oweals/openwrt.git/blob

   1 From e025da3d7aa4770bb1d1b3b0aa7cc4da1744852d Mon Sep 17 00:00:00 2001
   2 From: Dan Carpenter <dan.carpenter@oracle.com>
   3 Date: Wed, 24 Apr 2019 12:52:18 +0300
   4 Subject: [PATCH] brcm80211: potential NULL dereference in
   5  brcmf_cfg80211_vndr_cmds_dcmd_handler()
   6
   7 If "ret_len" is negative then it could lead to a NULL dereference.
   8
   9 The "ret_len" value comes from nl80211_vendor_cmd(), if it's negative
  10 then we don't allocate the "dcmd_buf" buffer.  Then we pass "ret_len" to
  11 brcmf_fil_cmd_data_set() where it is cast to a very high u32 value.
  12 Most of the functions in that call tree check whether the buffer we pass
  13 is NULL but there are at least a couple places which don't such as
  14 brcmf_dbg_hex_dump() and brcmf_msgbuf_query_dcmd().  We memcpy() to and
  15 from the buffer so it would result in a NULL dereference.
  16
  17 The fix is to change the types so that "ret_len" can't be negative.  (If
  18 we memcpy() zero bytes to NULL, that's a no-op and doesn't cause an
  19 issue).
  20
  21 Fixes: 1bacb0487d0e ("brcmfmac: replace cfg80211 testmode with vendor command")
  22 Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
  23 Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
  24 ---
  25  drivers/net/wireless/broadcom/brcm80211/brcmfmac/vendor.c | 5 +++--
  26  1 file changed, 3 insertions(+), 2 deletions(-)
  27
  28 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/vendor.c
  29 +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/vendor.c
  30 @@ -35,9 +35,10 @@ static int brcmf_cfg80211_vndr_cmds_dcmd
  31         struct brcmf_if *ifp;
  32         const struct brcmf_vndr_dcmd_hdr *cmdhdr = data;
  33         struct sk_buff *reply;
  34 -       int ret, payload, ret_len;
  35 +       unsigned int payload, ret_len;
  36         void *dcmd_buf = NULL, *wr_pointer;
  37         u16 msglen, maxmsglen = PAGE_SIZE - 0x100;
  38 +       int ret;
  39
  40         if (len < sizeof(*cmdhdr)) {
  41                 brcmf_err("vendor command too short: %d\n", len);
  42 @@ -65,7 +66,7 @@ static int brcmf_cfg80211_vndr_cmds_dcmd
  43                         brcmf_err("oversize return buffer %d\n", ret_len);
  44                         ret_len = BRCMF_DCMD_MAXLEN;
  45                 }
  46 -               payload = max(ret_len, len) + 1;
  47 +               payload = max_t(unsigned int, ret_len, len) + 1;
  48                 dcmd_buf = vzalloc(payload);
  49                 if (NULL == dcmd_buf)
  50                         return -ENOMEM;