#ifndef __UHID_H_ #define __UHID_H_ /* * User-space I/O driver support for HID subsystem * Copyright (c) 2012 David Herrmann */ /* * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the Free * Software Foundation; either version 2 of the License, or (at your option) * any later version. */ /* * Public header for user-space communication. We try to keep every structure * aligned but to be safe we also use __attribute__((__packed__)). Therefore, * the communication should be ABI compatible even between architectures. */ #include #include #include enum uhid_event_type { __UHID_LEGACY_CREATE, UHID_DESTROY, UHID_START, UHID_STOP, UHID_OPEN, UHID_CLOSE, UHID_OUTPUT, __UHID_LEGACY_OUTPUT_EV, __UHID_LEGACY_INPUT, UHID_GET_REPORT, UHID_GET_REPORT_REPLY, UHID_CREATE2, UHID_INPUT2, UHID_SET_REPORT, UHID_SET_REPORT_REPLY, }; struct uhid_create2_req { __u8 name[128]; __u8 phys[64]; __u8 uniq[64]; __u16 rd_size; __u16 bus; __u32 vendor; __u32 product; __u32 version; __u32 country; __u8 rd_data[HID_MAX_DESCRIPTOR_SIZE]; } __attribute__((__packed__)); enum uhid_dev_flag { UHID_DEV_NUMBERED_FEATURE_REPORTS = (1ULL << 0), UHID_DEV_NUMBERED_OUTPUT_REPORTS = (1ULL << 1), UHID_DEV_NUMBERED_INPUT_REPORTS = (1ULL << 2), }; struct uhid_start_req { __u64 dev_flags; }; #define UHID_DATA_MAX 4096 enum uhid_report_type { UHID_FEATURE_REPORT, UHID_OUTPUT_REPORT, UHID_INPUT_REPORT, }; struct uhid_input2_req { __u16 size; __u8 data[UHID_DATA_MAX]; } __attribute__((__packed__)); struct uhid_output_req { __u8 data[UHID_DATA_MAX]; __u16 size; __u8 rtype; } __attribute__((__packed__)); struct uhid_get_report_req { __u32 id; __u8 rnum; __u8 rtype; } __attribute__((__packed__)); struct uhid_get_report_reply_req { __u32 id; __u16 err; __u16 size; __u8 data[UHID_DATA_MAX]; } __attribute__((__packed__)); struct uhid_set_report_req { __u32 id; __u8 rnum; __u8 rtype; __u16 size; __u8 data[UHID_DATA_MAX]; } __attribute__((__packed__)); struct uhid_set_report_reply_req { __u32 id; __u16 err; } __attribute__((__packed__)); /* * Compat Layer * All these commands and requests are obsolete. You should avoid using them in * new code. We support them for backwards-compatibility, but you might not get * access to new feature in case you use them. */ enum uhid_legacy_event_type { UHID_CREATE = __UHID_LEGACY_CREATE, UHID_OUTPUT_EV = __UHID_LEGACY_OUTPUT_EV, UHID_INPUT = __UHID_LEGACY_INPUT, UHID_FEATURE = UHID_GET_REPORT, UHID_FEATURE_ANSWER = UHID_GET_REPORT_REPLY, }; /* Obsolete! Use UHID_CREATE2. */ struct uhid_create_req { __u8 name[128]; __u8 phys[64]; __u8 uniq[64]; __u8 __user *rd_data; __u16 rd_size; __u16 bus; __u32 vendor; __u32 product; __u32 version; __u32 country; } __attribute__((__packed__)); /* Obsolete! Use UHID_INPUT2. */ struct uhid_input_req { __u8 data[UHID_DATA_MAX]; __u16 size; } __attribute__((__packed__)); /* Obsolete! Kernel uses UHID_OUTPUT exclusively now. */ struct uhid_output_ev_req { __u16 type; __u16 code; __s32 value; } __attribute__((__packed__)); /* Obsolete! Kernel uses ABI compatible UHID_GET_REPORT. */ struct uhid_feature_req { __u32 id; __u8 rnum; __u8 rtype; } __attribute__((__packed__)); /* Obsolete! Use ABI compatible UHID_GET_REPORT_REPLY. */ struct uhid_feature_answer_req { __u32 id; __u16 err; __u16 size; __u8 data[UHID_DATA_MAX]; } __attribute__((__packed__)); /* * UHID Events * All UHID events from and to the kernel are encoded as "struct uhid_event". * The "type" field contains a UHID_* type identifier. All payload depends on * that type and can be accessed via ev->u.XYZ accordingly. * If user-space writes short events, they're extended with 0s by the kernel. If * the kernel writes short events, user-space shall extend them with 0s. */ struct uhid_event { __u32 type; union { struct uhid_create_req create; struct uhid_input_req input; struct uhid_output_req output; struct uhid_output_ev_req output_ev; struct uhid_feature_req feature; struct uhid_get_report_req get_report; struct uhid_feature_answer_req feature_answer; struct uhid_get_report_reply_req get_report_reply; struct uhid_create2_req create2; struct uhid_input2_req input2; struct uhid_set_report_req set_report; struct uhid_set_report_reply_req set_report_reply; struct uhid_start_req start; } u; } __attribute__((__packed__)); #endif /* __UHID_H_ */ 17-01-27 09:19:48 +0100 commit191e885a2e130e639bb0c8ee350d7047294f2ce6 (patch) tree9bf9f9b4971df55a46e0a6750d3f6cd37bf1d9f0 /include/net parent49def1853334396f948dcb4cedb9347abb318df5 (diff)
firmware: fix NULL pointer dereference in __fw_load_abort()
Since commit 5d47ec02c37ea6 ("firmware: Correct handling of fw_state_wait() return value") fw_load_abort() could be called twice and lead us to a kernel crash. This happens only when the firmware fallback mechanism (regular or custom) is used. The fallback mechanism exposes a sysfs interface for userspace to upload a file and notify the kernel when the file is loaded and ready, or to cancel an upload by echo'ing -1 into on the loading file: echo -n "-1" > /sys/$DEVPATH/loading This will call fw_load_abort(). Some distributions actually have a udev rule in place to *always* immediately cancel all firmware fallback mechanism requests (Debian), they have: $ cat /lib/udev/rules.d/50-firmware.rules # stub for immediately telling the kernel that userspace firmware loading # failed; necessary to avoid long timeouts with CONFIG_FW_LOADER_USER_HELPER=y SUBSYSTEM=="firmware", ACTION=="add", ATTR{loading}="-1 Distributions with this udev rule would run into this crash only if the fallback mechanism is used. Since most distributions disable by default using the fallback mechanism (CONFIG_FW_LOADER_USER_HELPER_FALLBACK), this would typicaly mean only 2 drivers which *require* the fallback mechanism could typically incur a crash: drivers/firmware/dell_rbu.c and the drivers/leds/leds-lp55xx-common.c driver. Distributions enabling CONFIG_FW_LOADER_USER_HELPER_FALLBACK by default are obviously more exposed to this crash. The crash happens because after commit 5b029624948d ("firmware: do not use fw_lock for fw_state protection") and subsequent fix commit 5d47ec02c37ea6 ("firmware: Correct handling of fw_state_wait() return value") a race can happen between this cancelation and the firmware fw_state_wait_timeout() being woken up after a state change with which fw_load_abort() as that calls swake_up(). Upon error fw_state_wait_timeout() will also again call fw_load_abort() and trigger a null reference. At first glance we could just fix this with a !buf check on fw_load_abort() before accessing buf->fw_st, however there is a logical issue in having a state machine used for the fallback mechanism and preventing access from it once we abort as its inside the buf (buf->fw_st). The firmware_class.c code is setting the buf to NULL to annotate an abort has occurred. Replace this mechanism by simply using the state check instead. All the other code in place already uses similar checks for aborting as well so no further changes are needed. An oops can be reproduced with the new fw_fallback.sh fallback mechanism cancellation test. Either cancelling the fallback mechanism or the custom fallback mechanism triggers a crash. mcgrof@piggy ~/linux-next/tools/testing/selftests/firmware (git::20170111-fw-fixes)$ sudo ./fw_fallback.sh ./fw_fallback.sh: timeout works ./fw_fallback.sh: firmware comparison works ./fw_fallback.sh: fallback mechanism works [ this then sits here when it is trying the cancellation test ] Kernel log: test_firmware: loading 'nope-test-firmware.bin' misc test_firmware: Direct firmware load for nope-test-firmware.bin failed with error -2 misc test_firmware: Falling back to user helper BUG: unable to handle kernel NULL pointer dereference at 0000000000000038 IP: _request_firmware+0xa27/0xad0 PGD 0 Oops: 0000 [#1] SMP Modules linked in: test_firmware(E) ... etc ... CPU: 1 PID: 1396 Comm: fw_fallback.sh Tainted: G W E 4.10.0-rc3-next-20170111+ #30 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.1-0-g8891697-prebuilt.qemu-project.org 04/01/2014 task: ffff9740b27f4340 task.stack: ffffbb15c0bc8000 RIP: 0010:_request_firmware+0xa27/0xad0 RSP: 0018:ffffbb15c0bcbd10 EFLAGS: 00010246 RAX: 00000000fffffffe RBX: ffff9740afe5aa80 RCX: 0000000000000000 RDX: ffff9740b27f4340 RSI: 0000000000000283 RDI: 0000000000000000 RBP: ffffbb15c0bcbd90 R08: ffffbb15c0bcbcd8 R09: 0000000000000000 R10: 0000000894a0d4b1 R11: 000000000000008c R12: ffffffffc0312480 R13: 0000000000000005 R14: ffff9740b1c32400 R15: 00000000000003e8 FS: 00007f8604422700(0000) GS:ffff9740bfc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000038 CR3: 000000012164c000 CR4: 00000000000006e0 Call Trace: request_firmware+0x37/0x50 trigger_request_store+0x79/0xd0 [test_firmware] dev_attr_store+0x18/0x30 sysfs_kf_write+0x37/0x40 kernfs_fop_write+0x110/0x1a0 __vfs_write+0x37/0x160 ? _cond_resched+0x1a/0x50 vfs_write+0xb5/0x1a0 SyS_write+0x55/0xc0 ? trace_do_page_fault+0x37/0xd0 entry_SYSCALL_64_fastpath+0x1e/0xad RIP: 0033:0x7f8603f49620 RSP: 002b:00007fff6287b788 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000055c307b110a0 RCX: 00007f8603f49620 RDX: 0000000000000016 RSI: 000055c3084d8a90 RDI: 0000000000000001 RBP: 0000000000000016 R08: 000000000000c0ff R09: 000055c3084d6336 R10: 000055c307b108b0 R11: 0000000000000246 R12: 000055c307b13c80 R13: 000055c3084d6320 R14: 0000000000000000 R15: 00007fff6287b950 Code: 9f 64 84 e8 9c 61 fe ff b8 f4 ff ff ff e9 6b f9 ff ff 48 c7 c7 40 6b 8d 84 89 45 a8 e8 43 84 18 00 49 8b be 00 03 00 00 8b 45 a8 <83> 7f 38 02 74 08 e8 6e ec ff ff 8b 45 a8 49 c7 86 00 03 00 00 RIP: _request_firmware+0xa27/0xad0 RSP: ffffbb15c0bcbd10 CR2: 0000000000000038 ---[ end trace 6d94ac339c133e6f ]--- Fixes: 5d47ec02c37e ("firmware: Correct handling of fw_state_wait() return value") Reported-and-Tested-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reported-and-Tested-by: Patrick Bruenn <p.bruenn@beckhoff.com> Reported-by: Chris Wilson <chris@chris-wilson.co.uk> CC: <stable@vger.kernel.org> [3.10+] Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/net')