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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "Pali Rohár" <pali@kernel.org>,
	"David S . Miller" <davem@davemloft.net>,
	"Sasha Levin" <sashal@kernel.org>
Subject: [PATCH 4.9 05/43] ppp: Fix generating ifname when empty IFLA_IFNAME is specified
Date: Tue, 24 Aug 2021 13:05:36 -0400	[thread overview]
Message-ID: <20210824170614.710813-6-sashal@kernel.org> (raw)
In-Reply-To: <20210824170614.710813-1-sashal@kernel.org>

From: Pali Rohár <pali@kernel.org>

[ Upstream commit 2459dcb96bcba94c08d6861f8a050185ff301672 ]

IFLA_IFNAME is nul-term string which means that IFLA_IFNAME buffer can be
larger than length of string which contains.

Function __rtnl_newlink() generates new own ifname if either IFLA_IFNAME
was not specified at all or userspace passed empty nul-term string.

It is expected that if userspace does not specify ifname for new ppp netdev
then kernel generates one in format "ppp<id>" where id matches to the ppp
unit id which can be later obtained by PPPIOCGUNIT ioctl.

And it works in this way if IFLA_IFNAME is not specified at all. But it
does not work when IFLA_IFNAME is specified with empty string.

So fix this logic also for empty IFLA_IFNAME in ppp_nl_newlink() function
and correctly generates ifname based on ppp unit identifier if userspace
did not provided preferred ifname.

Without this patch when IFLA_IFNAME was specified with empty string then
kernel created a new ppp interface in format "ppp<id>" but id did not
match ppp unit id returned by PPPIOCGUNIT ioctl. In this case id was some
number generated by __rtnl_newlink() function.

Signed-off-by: Pali Rohár <pali@kernel.org>
Fixes: bb8082f69138 ("ppp: build ifname using unit identifier for rtnl based devices")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ppp/ppp_generic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index 5ba472691546..0a29844676f9 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -1136,7 +1136,7 @@ static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
 	 * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
 	 * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
 	 */
-	if (!tb[IFLA_IFNAME])
+	if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
 		conf.ifname_is_set = false;
 
 	err = ppp_dev_configure(src_net, dev, &conf);
-- 
2.30.2


  parent reply	other threads:[~2021-08-24 17:36 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-24 17:05 [PATCH 4.9 00/43] 4.9.281-rc1 review Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 01/43] iio: adc: Fix incorrect exit of for-loop Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 02/43] ASoC: intel: atom: Fix reference to PCM buffer address Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 03/43] i2c: dev: zero out array used for i2c reads from userspace Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 04/43] ACPI: NFIT: Fix support for virtual SPA ranges Sasha Levin
2021-08-24 17:05 ` Sasha Levin [this message]
2021-08-24 17:05 ` [PATCH 4.9 06/43] net: Fix memory leak in ieee802154_raw_deliver Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 07/43] net: bridge: fix memleak in br_add_if() Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 08/43] tcp_bbr: fix u32 wrap bug in round logic if bbr_init() called after 2B packets Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 09/43] xen/events: Fix race in set_evtchn_to_irq Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 10/43] x86/tools: Fix objdump version check again Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 11/43] PCI/MSI: Enable and mask MSI-X early Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 12/43] PCI/MSI: Do not set invalid bits in MSI mask Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 13/43] PCI/MSI: Correct misleading comments Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 14/43] PCI/MSI: Use msi_mask_irq() in pci_msi_shutdown() Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 15/43] PCI/MSI: Protect msi_desc::masked for multi-MSI Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 16/43] PCI/MSI: Mask all unused MSI-X entries Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 17/43] PCI/MSI: Enforce that MSI-X table entry is masked for update Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 18/43] PCI/MSI: Enforce MSI[X] entry updates to be visible Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 19/43] vmlinux.lds.h: Handle clang's module.{c,d}tor sections Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 20/43] mac80211: drop data frames without key on encrypted links Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 21/43] KVM: nSVM: avoid picking up unsupported bits from L2 in int_ctl (CVE-2021-3653) Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 22/43] x86/fpu: Make init_fpstate correct with optimized XSAVE Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 23/43] dmaengine: usb-dmac: Fix PM reference leak in usb_dmac_probe() Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 24/43] ARM: dts: am43x-epos-evm: Reduce i2c0 bus speed for tps65218 Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 25/43] dmaengine: of-dma: router_xlate to return -EPROBE_DEFER if controller is not yet available Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 26/43] scsi: megaraid_mm: Fix end of loop tests for list_for_each_entry() Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 27/43] scsi: scsi_dh_rdac: Avoid crash during rdac_bus_attach() Sasha Levin
2021-08-24 17:05 ` [PATCH 4.9 28/43] scsi: core: Avoid printing an error if target_alloc() returns -ENXIO Sasha Levin
2021-08-24 17:06 ` [PATCH 4.9 29/43] ARM: dts: nomadik: Fix up interrupt controller node names Sasha Levin
2021-08-24 17:06 ` [PATCH 4.9 30/43] Bluetooth: hidp: use correct wait queue when removing ctrl_wait Sasha Levin
2021-08-24 17:06 ` [PATCH 4.9 31/43] dccp: add do-while-0 stubs for dccp_pr_debug macros Sasha Levin
2021-08-24 17:06 ` [PATCH 4.9 32/43] vhost: Fix the calculation in vhost_overflow() Sasha Levin
2021-08-24 17:06 ` [PATCH 4.9 33/43] net: 6pack: fix slab-out-of-bounds in decode_data Sasha Levin
2021-08-24 17:06 ` [PATCH 4.9 34/43] net: qlcnic: add missed unlock in qlcnic_83xx_flash_read32 Sasha Levin
2021-08-24 17:06 ` [PATCH 4.9 35/43] mmc: dw_mmc: call the dw_mci_prep_stop_abort() by default Sasha Levin
2021-08-24 17:06 ` [PATCH 4.9 36/43] mmc: dw_mmc: Fix hang on data CRC error Sasha Levin
2021-08-24 17:06 ` [PATCH 4.9 37/43] ALSA: hda - fix the 'Capture Switch' value change notifications Sasha Levin
2021-08-24 17:06 ` [PATCH 4.9 38/43] ipack: tpci200: fix many double free issues in tpci200_pci_probe Sasha Levin
2021-08-24 17:06 ` [PATCH 4.9 39/43] btrfs: prevent rename2 from exchanging a subvol with a directory from different parents Sasha Levin
2021-08-24 17:06 ` [PATCH 4.9 40/43] ASoC: intel: atom: Fix breakage for PCM buffer address setup Sasha Levin
2021-08-24 17:06 ` [PATCH 4.9 41/43] locks: print a warning when mount fails due to lack of "mand" support Sasha Levin
2021-08-24 17:06 ` [PATCH 4.9 42/43] fs: warn about impending deprecation of mandatory locks Sasha Levin
2021-08-24 17:06 ` [PATCH 4.9 43/43] Linux 4.9.281-rc1 Sasha Levin
2021-08-25 20:26 ` [PATCH 4.9 00/43] 4.9.281-rc1 review Guenter Roeck
2021-08-25 21:17 ` Daniel Díaz
2021-08-25 22:37 ` Shuah Khan

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