Re: [PATCH] staging: bcm2835-audio: Replace unsafe strcpy() with strscpy()

From: Nicolas Saenz Julienne
Date: Tue Feb 09 2021 - 12:01:06 EST

On Fri, 2021-02-05 at 08:25 +0100, Juerg Haefliger wrote:
> Replace strcpy() with strscpy() in bcm2835-audio/bcm2835.c to prevent the
> following when loading snd-bcm2835:
>
> [ 58.480634] ------------[ cut here ]------------
> [ 58.485321] kernel BUG at lib/string.c:1149!
> [ 58.489650] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
> [ 58.495214] Modules linked in: snd_bcm2835(COE+) snd_pcm snd_timer snd dm_multipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua btsdio bluetooth ecdh_generic ecc bcm2835_v4l2(CE) bcm2835_codec(CE) brcmfmac bcm2835_isp(CE) bcm2835_mmal_vchiq(CE) brcmutil cfg80211 v4l2_mem2mem videobuf2_vmalloc videobuf2_dma_contig videobuf2_memops raspberrypi_hwmon videobuf2_v4l2 videobuf2_common videodev bcm2835_gpiomem mc vc_sm_cma(CE) rpivid_mem uio_pdrv_genirq uio sch_fq_codel drm ip_tables x_tables autofs4 btrfs blake2b_generic raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor xor_neon raid6_pq libcrc32c raid1 raid0 multipath linear dwc2 roles spidev udc_core crct10dif_ce xhci_pci xhci_pci_renesas phy_generic aes_neon_bs aes_neon_blk crypto_simd cryptd
> [ 58.563787] CPU: 3 PID: 1959 Comm: insmod Tainted: G C OE 5.11.0-1001-raspi #1
> [ 58.572172] Hardware name: Raspberry Pi 4 Model B Rev 1.2 (DT)
> [ 58.578086] pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--)
> [ 58.584178] pc : fortify_panic+0x20/0x24
> [ 58.588161] lr : fortify_panic+0x20/0x24
> [ 58.592136] sp : ffff800010a83990
> [ 58.595491] x29: ffff800010a83990 x28: 0000000000000002
> [ 58.600879] x27: ffffb0b07cb72928 x26: 0000000000000000
> [ 58.606268] x25: ffff39e884973838 x24: ffffb0b07cb74190
> [ 58.611655] x23: ffffb0b07cb72030 x22: 0000000000000000
> [ 58.617042] x21: ffff39e884973014 x20: ffff39e88b793010
> [ 58.622428] x19: ffffb0b07cb72670 x18: 0000000000000030
> [ 58.627814] x17: 0000000000000000 x16: ffffb0b092ce2c1c
> [ 58.633200] x15: ffff39e88b901500 x14: 0720072007200720
> [ 58.638588] x13: 0720072007200720 x12: 0720072007200720
> [ 58.643979] x11: ffffb0b0936cbdf0 x10: 00000000fffff000
> [ 58.649366] x9 : ffffb0b09220cfa8 x8 : 0000000000000000
> [ 58.654752] x7 : ffffb0b093673df0 x6 : ffffb0b09364e000
> [ 58.660140] x5 : 0000000000000000 x4 : ffff39e93b7db948
> [ 58.665526] x3 : ffff39e93b7ebcf0 x2 : 0000000000000000
> [ 58.670913] x1 : 0000000000000000 x0 : 0000000000000022
> [ 58.676299] Call trace:
> [ 58.678775] fortify_panic+0x20/0x24
> [ 58.682402] snd_bcm2835_alsa_probe+0x5b8/0x7d8 [snd_bcm2835]
> [ 58.688247] platform_probe+0x74/0xe4
> [ 58.691963] really_probe+0xf0/0x510
> [ 58.695585] driver_probe_device+0xe0/0x100
> [ 58.699826] device_driver_attach+0xcc/0xd4
> [ 58.704068] __driver_attach+0xb0/0x17c
> [ 58.707956] bus_for_each_dev+0x7c/0xd4
> [ 58.711843] driver_attach+0x30/0x40
> [ 58.715467] bus_add_driver+0x154/0x250
> [ 58.719354] driver_register+0x84/0x140
> [ 58.723242] __platform_driver_register+0x34/0x40
> [ 58.728013] bcm2835_alsa_driver_init+0x30/0x1000 [snd_bcm2835]
> [ 58.734024] do_one_initcall+0x54/0x300
> [ 58.737914] do_init_module+0x60/0x280
> [ 58.741719] load_module+0x680/0x770
> [ 58.745344] __do_sys_finit_module+0xbc/0x130
> [ 58.749761] __arm64_sys_finit_module+0x2c/0x40
> [ 58.754356] el0_svc_common.constprop.0+0x88/0x220
> [ 58.759216] do_el0_svc+0x30/0xa0
> [ 58.762575] el0_svc+0x28/0x70
> [ 58.765669] el0_sync_handler+0x1a4/0x1b0
> [ 58.769732] el0_sync+0x178/0x180
> [ 58.773095] Code: aa0003e1 91366040 910003fd 97ffee21 (d4210000)
> [ 58.779275] ---[ end trace 29be5b17497bd898 ]---
> [ 58.783955] note: insmod[1959] exited with preempt_count 1
> [ 58.791921] ------------[ cut here ]------------
>
> For the sake of it, replace all the other occurences of strcpy() under
> bcm2835-audio/ as well.
>
> Signed-off-by: Juerg Haefliger <juergh@xxxxxxxxxxxxx>
> ---

Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>

Regards,
Nicolas

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