eaba3b2840
Unprivileged user can crash kernel by using DRM_IOCTL_NOUVEAU_CHANNEL_ALLOC ioctl. This was reported by trinity[1] fuzzer. [ 71.073906] nouveau 0000:01:00.0: crashme[1329]: channel failed to initialise, -17 [ 71.081730] BUG: kernel NULL pointer dereference, address: 00000000000000a0 [ 71.088928] #PF: supervisor read access in kernel mode [ 71.094059] #PF: error_code(0x0000) - not-present page [ 71.099189] PGD 119590067 P4D 119590067 PUD 1054f5067 PMD 0 [ 71.104842] Oops: 0000 [#1] SMP NOPTI [ 71.108498] CPU: 2 PID: 1329 Comm: crashme Not tainted 5.8.0-rc6+ #2 [ 71.114993] Hardware name: AMD Pike/Pike, BIOS RPK1506A 09/03/2014 [ 71.121213] RIP: 0010:nouveau_abi16_ioctl_channel_alloc+0x108/0x380 [nouveau] [ 71.128339] Code: 48 89 9d f0 00 00 00 41 8b 4c 24 04 41 8b 14 24 45 31 c0 4c 8d 4b 10 48 89 ee 4c 89 f7 e8 10 11 00 00 85 c0 75 78 48 8b 43 10 <8b> 90 a0 00 00 00 41 89 54 24 08 80 7d 3d 05 0f 86 bb 01 00 00 41 [ 71.147074] RSP: 0018:ffffb4a1809cfd38 EFLAGS: 00010246 [ 71.152526] RAX: 0000000000000000 RBX: ffff98cedbaa1d20 RCX: 00000000000003bf [ 71.159651] RDX: 00000000000003be RSI: 0000000000000000 RDI: 0000000000030160 [ 71.166774] RBP: ffff98cee776de00 R08: ffffdc0144198a08 R09: ffff98ceeefd4000 [ 71.173901] R10: ffff98cee7e81780 R11: 0000000000000001 R12: ffffb4a1809cfe08 [ 71.181214] R13: ffff98cee776d000 R14: ffff98cec519e000 R15: ffff98cee776def0 [ 71.188339] FS: 00007fd926250500(0000) GS:ffff98ceeac80000(0000) knlGS:0000000000000000 [ 71.196418] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 71.202155] CR2: 00000000000000a0 CR3: 0000000106622000 CR4: 00000000000406e0 [ 71.209297] Call Trace: [ 71.211777] ? nouveau_abi16_ioctl_getparam+0x1f0/0x1f0 [nouveau] [ 71.218053] drm_ioctl_kernel+0xac/0xf0 [drm] [ 71.222421] drm_ioctl+0x211/0x3c0 [drm] [ 71.226379] ? nouveau_abi16_ioctl_getparam+0x1f0/0x1f0 [nouveau] [ 71.232500] nouveau_drm_ioctl+0x57/0xb0 [nouveau] [ 71.237285] ksys_ioctl+0x86/0xc0 [ 71.240595] __x64_sys_ioctl+0x16/0x20 [ 71.244340] do_syscall_64+0x4c/0x90 [ 71.248110] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 71.253162] RIP: 0033:0x7fd925d4b88b [ 71.256731] Code: Bad RIP value. [ 71.259955] RSP: 002b:00007ffc743592d8 EFLAGS: 00000206 ORIG_RAX: 0000000000000010 [ 71.267514] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd925d4b88b [ 71.274637] RDX: 0000000000601080 RSI: 00000000c0586442 RDI: 0000000000000003 [ 71.281986] RBP: 00007ffc74359340 R08: 00007fd926016ce0 R09: 00007fd926016ce0 [ 71.289111] R10: 0000000000000003 R11: 0000000000000206 R12: 0000000000400620 [ 71.296235] R13: 00007ffc74359420 R14: 0000000000000000 R15: 0000000000000000 [ 71.303361] Modules linked in: rfkill sunrpc snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio snd_hda_intel snd_intel_dspcfg snd_hda_codec snd_hda_core edac_mce_amd snd_hwdep kvm_amd snd_seq ccp snd_seq_device snd_pcm kvm snd_timer snd irqbypass soundcore sp5100_tco pcspkr crct10dif_pclmul crc32_pclmul ghash_clmulni_intel wmi_bmof joydev i2c_piix4 fam15h_power k10temp acpi_cpufreq ip_tables xfs libcrc32c sd_mod t10_pi sg nouveau video mxm_wmi i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm broadcom bcm_phy_lib ata_generic ahci drm e1000 crc32c_intel libahci serio_raw tg3 libata firewire_ohci firewire_core wmi crc_itu_t dm_mirror dm_region_hash dm_log dm_mod [ 71.365269] CR2: 00000000000000a0 simplified reproducer ---------------------------------8<---------------------------------------- /* * gcc -o crashme crashme.c * ./crashme /dev/dri/renderD128 */ struct drm_nouveau_channel_alloc { uint32_t fb_ctxdma_handle; uint32_t tt_ctxdma_handle; int channel; uint32_t pushbuf_domains; /* Notifier memory */ uint32_t notifier_handle; /* DRM-enforced subchannel assignments */ struct { uint32_t handle; uint32_t grclass; } subchan[8]; uint32_t nr_subchan; }; static struct drm_nouveau_channel_alloc channel; int main(int argc, char *argv[]) { int fd; int rv; if (argc != 2) die("usage: %s <dev>", 0, argv[0]); if ((fd = open(argv[1], O_RDONLY)) == -1) die("open %s", errno, argv[1]); if (ioctl(fd, DRM_IOCTL_NOUVEAU_CHANNEL_ALLOC, &channel) == -1 && errno == EACCES) die("ioctl %s", errno, argv[1]); close(fd); printf("PASS\n"); return 0; } ---------------------------------8<---------------------------------------- [1] https://github.com/kernelslacker/trinity Fixes: eeaf06ac1a55 ("drm/nouveau/svm: initial support for shared virtual memory") Signed-off-by: Frantisek Hrbata <frantisek@hrbata.com> Reviewed-by: Karol Herbst <kherbst@redhat.com> Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.