[PATCH 6.19 016/220] bnxt_en: fix OOB access in DBG_BUF_PRODUCER async event handler

Greg Kroah-Hartman
2026-03-23T13:50:09Z

From: Junrui Luo <moonafterrain@outlook.com>

commit 64dcbde7f8f870a4f2d9daf24ffb06f9748b5dd3 upstream.

The ASYNC_EVENT_CMPL_EVENT_ID_DBG_BUF_PRODUCER handler in
bnxt_async_event_process() uses a firmware-supplied 'type' field
directly as an index into bp->bs_trace[] without bounds validation.

The 'type' field is a 16-bit value extracted from DMA-mapped completion
ring memory that the NIC writes directly to host RAM. A malicious or
compromised NIC can supply any value from 0 to 65535, causing an
out-of-bounds access into kernel heap memory.

The bnxt_bs_trace_check_wrap() call then dereferences bs_trace->magic_byte
and writes to bs_trace->last_offset and bs_trace->wrapped, leading to
kernel memory corruption or a crash.

Fix by adding a bounds check and defining BNXT_TRACE_MAX as
DBG_LOG_BUFFER_FLUSH_REQ_TYPE_ERR_QPC_TRACE + 1 to cover all currently
defined firmware trace types (0x0 through 0xc).

Fixes: 84fcd9449fd7 ("bnxt_en: Manage the FW trace context memory")
Reported-by: Yuhao Jiang <danisjiang@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Junrui Luo <moonafterrain@outlook.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Link: https://patch.msgid.link/SYBPR01MB7881A253A1C9775D277F30E9AF42A@SYBPR01MB7881.ausprd01.prod.outlook.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/broadcom/bnxt/bnxt.c | 2 ++
drivers/net/ethernet/broadcom/bnxt/bnxt.h | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -2927,6 +2927,8 @@ static int bnxt_async_event_process(stru
u16 type = (u16)BNXT_EVENT_BUF_PRODUCER_TYPE(data1);
u32 offset = BNXT_EVENT_BUF_PRODUCER_OFFSET(data2);

+ if (type >= ARRAY_SIZE(bp->bs_trace))
+ goto async_event_process_exit;
bnxt_bs_trace_check_wrap(&bp->bs_trace[type], offset);
goto async_event_process_exit;
}
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
@@ -2135,7 +2135,7 @@ enum board_idx {
};

#define BNXT_TRACE_BUF_MAGIC_BYTE ((u8)0xbc)
-#define BNXT_TRACE_MAX 11
+#define BNXT_TRACE_MAX (DBG_LOG_BUFFER_FLUSH_REQ_TYPE_ERR_QPC_TRACE + 1)

struct bnxt_bs_trace_info {
u8 *magic_byte;