Re: [PATCH net v3 2/3] ieee802154: ca8210: prevent stack buffer overflow in hwme_get_request_sync()
From: David Laight <hidden>
Date: 2026-09-22 09:47:39
Also in:
lkml, stable
On Tue, 22 Sep 2026 09:30:24 +0000 Hui Peng [off-list ref] wrote:
In ca8210_get_ed(), an uninitialized u8 lenvar and a pointer to a 1-byte stack buffer (u8 *level) are passed to hwme_get_request_sync(), which unconditionally copies response.pdata.hwme_get_cnf.hw_attribute_length bytes into hw_attribute_value without checking the caller's destination buffer capacity, overflowing level on the stack when hw_attribute_length exceeds 1: BUG: KASAN: stack-out-of-bounds in hwme_get_request_sync.constprop.0.isra.0+0xf3/0x170 Write of size 16 at addr ffff888001907780 by task init/1 Call Trace: <TASK> dump_stack_lvl+0x70/0xa0 print_report+0x153/0x4c6 kasan_report+0xf1/0x120 kasan_check_range+0x125/0x200 __asan_memcpy+0x3c/0x60 hwme_get_request_sync.constprop.0.isra.0+0xf3/0x170 ca8210_get_ed+0x9c/0xf0 ... The buggy address belongs to stack of task init/1 and is located at offset 48 in frame: ca8210_get_ed+0x0/0xf0 This frame has 2 objects: [48, 49) 'level' [64, 65) 'lenvar' Initialize lenvar = 1 in ca8210_get_ed() and return IEEE802154_SYSTEM_ERROR in hwme_get_request_sync() if response.pdata.hwme_get_cnf.hw_attribute_length exceeds *hw_attribute_length.
This function is silly. There is exactly one caller, the only valid length seems to 1 (is zero valid?), not much point using memcpy() either. David
quoted hunk ↗ jump to hunk
Tested in QEMU with KASAN enabled by passing an oversized hw_attribute_length response into ca8210_get_ed(). Fixes: ded845a781a5 ("ieee802154: Add CA8210 IEEE 802.15.4 device driver") Cc: stable@vger.kernel.org Assisted-by: LLM Signed-off-by: Hui Peng <redacted> --- Changes in v3: - No changes. Changes in v2: - Split out as patch 2/3. - Replaced the temporary stack buffer in ca8210_get_ed() with lenvar = 1 and an upper-bound check against *hw_attribute_length in hwme_get_request_sync() as requested by Miquel Raynal. drivers/net/ieee802154/ca8210.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)diff --git a/drivers/net/ieee802154/ca8210.c b/drivers/net/ieee802154/ca8210.c index a990a0f..8aa7ffe 100644 --- a/drivers/net/ieee802154/ca8210.c +++ b/drivers/net/ieee802154/ca8210.c@@ -1677,6 +1677,9 @@ static u8 hwme_get_request_sync( return IEEE802154_SYSTEM_ERROR; if (response.pdata.hwme_get_cnf.status == IEEE802154_SUCCESS) { + if (response.pdata.hwme_get_cnf.hw_attribute_length > + *hw_attribute_length) + return IEEE802154_SYSTEM_ERROR; *hw_attribute_length = response.pdata.hwme_get_cnf.hw_attribute_length; memcpy(@@ -2027,7 +2030,7 @@ static int ca8210_xmit_async(struct ieee802154_hw *hw, struct sk_buff *skb) */ static int ca8210_get_ed(struct ieee802154_hw *hw, u8 *level) { - u8 lenvar; + u8 lenvar = 1; struct ca8210_priv *priv = hw->priv; return link_to_linux_err(