brcm80211: potential NULL dereference in brcmf_cfg80211_vndr_cmds_dcmd_handler()

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If "ret_len" is negative then it could lead to a NULL dereference.

The "ret_len" value comes from nl80211_vendor_cmd(), if it's negative
then we don't allocate the "dcmd_buf" buffer.  Then we pass "ret_len" to
brcmf_fil_cmd_data_set() where it is cast to a very high u32 value.
Most of the functions in that call tree check whether the buffer we pass
is NULL but there are at least a couple places which don't such as
brcmf_dbg_hex_dump() and brcmf_msgbuf_query_dcmd().  We memcpy() to and
from the buffer so it would result in a NULL dereference.

The fix is to change the types so that "ret_len" can't be negative.  (If
we memcpy() zero bytes to NULL, that's a no-op and doesn't cause an
issue).

Fixes: 1bacb0487d ("brcmfmac: replace cfg80211 testmode with vendor command")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

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Dan Carpenter 2019-04-24 12:52:18 +03:00 • committed by Kalle Valo

parent e3037485c6

commit e025da3d7a

1 changed files with 3 additions and 2 deletions

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drivers/net/wireless/broadcom/brcm80211/brcmfmac/vendor.c

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