From e985ba7ed26e5b708c5d22a597c4b06a683fe92e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marcin=20Wcis=C5=82o?= Date: Mon, 23 Jun 2025 00:13:57 +0200 Subject: [PATCH] net: mdio: fix undefined behavior in bit shift for __mdiobus_register MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit jira VULN-66416 cve CVE-2022-49907 commit-author Gaosheng Cui commit 40e4eb324c59e11fcb927aa46742d28aba6ecb8a Shifting signed 32-bit value by 31 bits is undefined, so changing significant bit to unsigned. The UBSAN warning calltrace like below: UBSAN: shift-out-of-bounds in drivers/net/phy/mdio_bus.c:586:27 left shift of 1 by 31 places cannot be represented in type 'int' Call Trace: dump_stack_lvl+0x7d/0xa5 dump_stack+0x15/0x1b ubsan_epilogue+0xe/0x4e __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c __mdiobus_register+0x49d/0x4e0 fixed_mdio_bus_init+0xd8/0x12d do_one_initcall+0x76/0x430 kernel_init_freeable+0x3b3/0x422 kernel_init+0x24/0x1e0 ret_from_fork+0x1f/0x30 Fixes: 4fd5f812c23c ("phylib: allow incremental scanning of an mii bus") Signed-off-by: Gaosheng Cui Reviewed-by: Andrew Lunn Link: https://lore.kernel.org/r/20221031132645.168421-1-cuigaosheng1@huawei.com Signed-off-by: Jakub Kicinski (cherry picked from commit 40e4eb324c59e11fcb927aa46742d28aba6ecb8a) Signed-off-by: Marcin Wcisło --- drivers/net/phy/mdio_bus.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c index e7bb6d88b46be..48243e0951ed5 100644 --- a/drivers/net/phy/mdio_bus.c +++ b/drivers/net/phy/mdio_bus.c @@ -566,7 +566,7 @@ int __mdiobus_register(struct mii_bus *bus, struct module *owner) } for (i = 0; i < PHY_MAX_ADDR; i++) { - if ((bus->phy_mask & (1 << i)) == 0) { + if ((bus->phy_mask & BIT(i)) == 0) { struct phy_device *phydev; phydev = mdiobus_scan(bus, i);