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Sender: Corey Minyard <tcminyard@gmail.com>
Date:   Tue, 12 Apr 2022 19:16:00 -0500
From:   Corey Minyard <minyard@acm.org>
To:     kernel test robot <lkp@intel.com>
Cc:     Kefeng Wang <wangkefeng.wang@huawei.com>, kbuild-all@lists.01.org,
        linux-kernel@vger.kernel.org,
        Catalin Marinas <catalin.marinas@arm.com>
Subject: Re: drivers/char/ipmi/ipmi_msghandler.c:5283:17: warning: 'strncpy'
 specified bound 11 equals destination size
Message-ID: <20220413001600.GD426325@minyard.net>
Reply-To: minyard@acm.org
References: <202204130109.hJ8G1iNz-lkp@intel.com>
MIME-Version: 1.0
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In-Reply-To: <202204130109.hJ8G1iNz-lkp@intel.com>
Precedence: bulk

On Wed, Apr 13, 2022 at 01:14:04AM +0800, kernel test robot wrote:
> Hi Kefeng,
> 
> FYI, the error/warning still remains.
> 
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   ce522ba9ef7e2d9fb22a39eb3371c0c64e2a433e
> commit: dd03762ab608e058c8f390ad9cf667e490089796 arm64: Enable KCSAN
> date:   4 months ago
> config: arm64-buildonly-randconfig-r003-20220412 (https://download.01.org/0day-ci/archive/20220413/202204130109.hJ8G1iNz-lkp@intel.com/config)
> compiler: aarch64-linux-gcc (GCC) 11.2.0
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dd03762ab608e058c8f390ad9cf667e490089796
>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>         git fetch --no-tags linus master
>         git checkout dd03762ab608e058c8f390ad9cf667e490089796
>         # save the config file to linux build tree
>         mkdir build_dir
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arm64 SHELL=/bin/bash
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All warnings (new ones prefixed by >>):
> 
>    drivers/char/ipmi/ipmi_msghandler.c: In function 'send_panic_events':
> >> drivers/char/ipmi/ipmi_msghandler.c:5283:17: warning: 'strncpy' specified bound 11 equals destination size [-Wstringop-truncation]
>     5283 |                 strncpy(data+5, p, 11);
>          |                 ^~~~~~~~~~~~~~~~~~~~~~

This is not a bug.  That's an 11 byte field that should be filled with
zeros at the end if the string is <11 bytes, but is not nil terminated
if it's 11 bytes.  So strncpy does exactly what is needed.

Is there any way to shut off this warning?

-corey

> 
> 
> vim +/strncpy +5283 drivers/char/ipmi/ipmi_msghandler.c
> 
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5143  
> a567b6230066e3 Corey Minyard  2018-04-05  5144  static void send_panic_events(struct ipmi_smi *intf, char *str)
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5145  {
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5146  	struct kernel_ipmi_msg msg;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5147  	unsigned char data[16];
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5148  	struct ipmi_system_interface_addr *si;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5149  	struct ipmi_addr addr;
> 91e2dd0a47bae1 Corey Minyard  2018-03-28  5150  	char *p = str;
> 91e2dd0a47bae1 Corey Minyard  2018-03-28  5151  	struct ipmi_ipmb_addr *ipmb;
> 91e2dd0a47bae1 Corey Minyard  2018-03-28  5152  	int j;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5153  
> 1c9f98d1bfbd06 Corey Minyard  2017-08-18  5154  	if (ipmi_send_panic_event == IPMI_SEND_PANIC_EVENT_NONE)
> 1c9f98d1bfbd06 Corey Minyard  2017-08-18  5155  		return;
> 1c9f98d1bfbd06 Corey Minyard  2017-08-18  5156  
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5157  	si = (struct ipmi_system_interface_addr *) &addr;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5158  	si->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5159  	si->channel = IPMI_BMC_CHANNEL;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5160  	si->lun = 0;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5161  
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5162  	/* Fill in an event telling that we have failed. */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5163  	msg.netfn = 0x04; /* Sensor or Event. */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5164  	msg.cmd = 2; /* Platform event command. */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5165  	msg.data = data;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5166  	msg.data_len = 8;
> cda315aba34ff4 Matt Domsch    2005-12-12  5167  	data[0] = 0x41; /* Kernel generator ID, IPMI table 5-4 */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5168  	data[1] = 0x03; /* This is for IPMI 1.0. */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5169  	data[2] = 0x20; /* OS Critical Stop, IPMI table 36-3 */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5170  	data[4] = 0x6f; /* Sensor specific, IPMI table 36-1 */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5171  	data[5] = 0xa1; /* Runtime stop OEM bytes 2 & 3. */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5172  
> c70d749986f6f1 Corey Minyard  2008-04-29  5173  	/*
> c70d749986f6f1 Corey Minyard  2008-04-29  5174  	 * Put a few breadcrumbs in.  Hopefully later we can add more things
> c70d749986f6f1 Corey Minyard  2008-04-29  5175  	 * to make the panic events more useful.
> c70d749986f6f1 Corey Minyard  2008-04-29  5176  	 */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5177  	if (str) {
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5178  		data[3] = str[0];
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5179  		data[6] = str[1];
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5180  		data[7] = str[2];
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5181  	}
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5182  
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5183  	/* Send the event announcing the panic. */
> 895dcfd1cab84d Corey Minyard  2012-03-28  5184  	ipmi_panic_request_and_wait(intf, &addr, &msg);
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5185  
> c70d749986f6f1 Corey Minyard  2008-04-29  5186  	/*
> c70d749986f6f1 Corey Minyard  2008-04-29  5187  	 * On every interface, dump a bunch of OEM event holding the
> c70d749986f6f1 Corey Minyard  2008-04-29  5188  	 * string.
> c70d749986f6f1 Corey Minyard  2008-04-29  5189  	 */
> 1c9f98d1bfbd06 Corey Minyard  2017-08-18  5190  	if (ipmi_send_panic_event != IPMI_SEND_PANIC_EVENT_STRING || !str)
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5191  		return;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5192  
> 78ba2faf71c639 Corey Minyard  2007-02-10  5193  	/*
> 78ba2faf71c639 Corey Minyard  2007-02-10  5194  	 * intf_num is used as an marker to tell if the
> 78ba2faf71c639 Corey Minyard  2007-02-10  5195  	 * interface is valid.  Thus we need a read barrier to
> 78ba2faf71c639 Corey Minyard  2007-02-10  5196  	 * make sure data fetched before checking intf_num
> 78ba2faf71c639 Corey Minyard  2007-02-10  5197  	 * won't be used.
> 78ba2faf71c639 Corey Minyard  2007-02-10  5198  	 */
> 78ba2faf71c639 Corey Minyard  2007-02-10  5199  	smp_rmb();
> 78ba2faf71c639 Corey Minyard  2007-02-10  5200  
> c70d749986f6f1 Corey Minyard  2008-04-29  5201  	/*
> c70d749986f6f1 Corey Minyard  2008-04-29  5202  	 * First job here is to figure out where to send the
> c70d749986f6f1 Corey Minyard  2008-04-29  5203  	 * OEM events.  There's no way in IPMI to send OEM
> c70d749986f6f1 Corey Minyard  2008-04-29  5204  	 * events using an event send command, so we have to
> c70d749986f6f1 Corey Minyard  2008-04-29  5205  	 * find the SEL to put them in and stick them in
> c70d749986f6f1 Corey Minyard  2008-04-29  5206  	 * there.
> c70d749986f6f1 Corey Minyard  2008-04-29  5207  	 */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5208  
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5209  	/* Get capabilities from the get device id. */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5210  	intf->local_sel_device = 0;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5211  	intf->local_event_generator = 0;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5212  	intf->event_receiver = 0;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5213  
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5214  	/* Request the device info from the local MC. */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5215  	msg.netfn = IPMI_NETFN_APP_REQUEST;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5216  	msg.cmd = IPMI_GET_DEVICE_ID_CMD;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5217  	msg.data = NULL;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5218  	msg.data_len = 0;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5219  	intf->null_user_handler = device_id_fetcher;
> 895dcfd1cab84d Corey Minyard  2012-03-28  5220  	ipmi_panic_request_and_wait(intf, &addr, &msg);
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5221  
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5222  	if (intf->local_event_generator) {
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5223  		/* Request the event receiver from the local MC. */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5224  		msg.netfn = IPMI_NETFN_SENSOR_EVENT_REQUEST;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5225  		msg.cmd = IPMI_GET_EVENT_RECEIVER_CMD;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5226  		msg.data = NULL;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5227  		msg.data_len = 0;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5228  		intf->null_user_handler = event_receiver_fetcher;
> 895dcfd1cab84d Corey Minyard  2012-03-28  5229  		ipmi_panic_request_and_wait(intf, &addr, &msg);
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5230  	}
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5231  	intf->null_user_handler = NULL;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5232  
> c70d749986f6f1 Corey Minyard  2008-04-29  5233  	/*
> c70d749986f6f1 Corey Minyard  2008-04-29  5234  	 * Validate the event receiver.  The low bit must not
> c70d749986f6f1 Corey Minyard  2008-04-29  5235  	 * be 1 (it must be a valid IPMB address), it cannot
> c70d749986f6f1 Corey Minyard  2008-04-29  5236  	 * be zero, and it must not be my address.
> c70d749986f6f1 Corey Minyard  2008-04-29  5237  	 */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5238  	if (((intf->event_receiver & 1) == 0)
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5239  	    && (intf->event_receiver != 0)
> 5fdb1fb2abe647 Corey Minyard  2017-09-05  5240  	    && (intf->event_receiver != intf->addrinfo[0].address)) {
> c70d749986f6f1 Corey Minyard  2008-04-29  5241  		/*
> c70d749986f6f1 Corey Minyard  2008-04-29  5242  		 * The event receiver is valid, send an IPMB
> c70d749986f6f1 Corey Minyard  2008-04-29  5243  		 * message.
> c70d749986f6f1 Corey Minyard  2008-04-29  5244  		 */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5245  		ipmb = (struct ipmi_ipmb_addr *) &addr;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5246  		ipmb->addr_type = IPMI_IPMB_ADDR_TYPE;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5247  		ipmb->channel = 0; /* FIXME - is this right? */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5248  		ipmb->lun = intf->event_receiver_lun;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5249  		ipmb->slave_addr = intf->event_receiver;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5250  	} else if (intf->local_sel_device) {
> c70d749986f6f1 Corey Minyard  2008-04-29  5251  		/*
> c70d749986f6f1 Corey Minyard  2008-04-29  5252  		 * The event receiver was not valid (or was
> c70d749986f6f1 Corey Minyard  2008-04-29  5253  		 * me), but I am an SEL device, just dump it
> c70d749986f6f1 Corey Minyard  2008-04-29  5254  		 * in my SEL.
> c70d749986f6f1 Corey Minyard  2008-04-29  5255  		 */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5256  		si = (struct ipmi_system_interface_addr *) &addr;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5257  		si->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5258  		si->channel = IPMI_BMC_CHANNEL;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5259  		si->lun = 0;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5260  	} else
> 91e2dd0a47bae1 Corey Minyard  2018-03-28  5261  		return; /* No where to send the event. */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5262  
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5263  	msg.netfn = IPMI_NETFN_STORAGE_REQUEST; /* Storage. */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5264  	msg.cmd = IPMI_ADD_SEL_ENTRY_CMD;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5265  	msg.data = data;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5266  	msg.data_len = 16;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5267  
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5268  	j = 0;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5269  	while (*p) {
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5270  		int size = strlen(p);
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5271  
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5272  		if (size > 11)
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5273  			size = 11;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5274  		data[0] = 0;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5275  		data[1] = 0;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5276  		data[2] = 0xf0; /* OEM event without timestamp. */
> 5fdb1fb2abe647 Corey Minyard  2017-09-05  5277  		data[3] = intf->addrinfo[0].address;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5278  		data[4] = j++; /* sequence # */
> c70d749986f6f1 Corey Minyard  2008-04-29  5279  		/*
> c70d749986f6f1 Corey Minyard  2008-04-29  5280  		 * Always give 11 bytes, so strncpy will fill
> c70d749986f6f1 Corey Minyard  2008-04-29  5281  		 * it with zeroes for me.
> c70d749986f6f1 Corey Minyard  2008-04-29  5282  		 */
> ^1da177e4c3f41 Linus Torvalds 2005-04-16 @5283  		strncpy(data+5, p, 11);
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5284  		p += size;
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5285  
> 895dcfd1cab84d Corey Minyard  2012-03-28  5286  		ipmi_panic_request_and_wait(intf, &addr, &msg);
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5287  	}
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5288  }
> ^1da177e4c3f41 Linus Torvalds 2005-04-16  5289  
> 
> :::::: The code at line 5283 was first introduced by commit
> :::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2
> 
> :::::: TO: Linus Torvalds <torvalds@ppc970.osdl.org>
> :::::: CC: Linus Torvalds <torvalds@ppc970.osdl.org>
> 
> -- 
> 0-DAY CI Kernel Test Service
> https://01.org/lkp