![Christian Borntraeger](/assets/img/avatar_default.png)
There is a memory leak in /proc/cio_ignore. The iterator is allocated in cio_ignore_proc_seq_start, but never freed in cio_ignore_proc_seq_stop, because we cannot use the iterator that was passed by seqfile. The seqfile interface passes the last seen iterator to the stop function and not the first one. Since our next function will return NULL at the end, the iter passed to cio_ignore_proc_seq_stop is NULL. The original iter has leaked. The solution is to use seq_open_private. Found with kmemleak: unreferenced object 0x1c720580 (size 32): comm "head", pid 973, jiffies 4294958302 hex dump (first 32 bytes): 00 00 00 00 00 00 00 04 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<0000000000203154>] kmem_cache_alloc+0x190/0x19c [<00000000003fb462>] cio_ignore_proc_seq_start+0x5e/0x128 [<0000000000231018>] seq_read+0xc8/0x4bc [<0000000000273954>] proc_reg_read+0xa8/0xf4 [<000000000020e3d8>] vfs_read+0xac/0x1a4 [<000000000020e5c6>] SyS_read+0x52/0xa8 [<000000000011836e>] sysc_noemu+0x10/0x16 [<0000004690b7936c>] 0x4690b7936c Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
404 lines
8.4 KiB
C
404 lines
8.4 KiB
C
/*
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* drivers/s390/cio/blacklist.c
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* S/390 common I/O routines -- blacklisting of specific devices
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*
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* Copyright (C) 1999-2002 IBM Deutschland Entwicklung GmbH,
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* IBM Corporation
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* Author(s): Ingo Adlung (adlung@de.ibm.com)
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* Cornelia Huck (cornelia.huck@de.ibm.com)
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* Arnd Bergmann (arndb@de.ibm.com)
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*/
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#define KMSG_COMPONENT "cio"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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#include <linux/init.h>
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#include <linux/vmalloc.h>
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#include <linux/slab.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/ctype.h>
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#include <linux/device.h>
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#include <asm/cio.h>
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#include <asm/uaccess.h>
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#include "blacklist.h"
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#include "cio.h"
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#include "cio_debug.h"
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#include "css.h"
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#include "device.h"
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/*
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* "Blacklisting" of certain devices:
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* Device numbers given in the commandline as cio_ignore=... won't be known
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* to Linux.
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*
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* These can be single devices or ranges of devices
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*/
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/* 65536 bits for each set to indicate if a devno is blacklisted or not */
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#define __BL_DEV_WORDS ((__MAX_SUBCHANNEL + (8*sizeof(long) - 1)) / \
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(8*sizeof(long)))
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static unsigned long bl_dev[__MAX_SSID + 1][__BL_DEV_WORDS];
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typedef enum {add, free} range_action;
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/*
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* Function: blacklist_range
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* (Un-)blacklist the devices from-to
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*/
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static int blacklist_range(range_action action, unsigned int from_ssid,
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unsigned int to_ssid, unsigned int from,
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unsigned int to, int msgtrigger)
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{
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if ((from_ssid > to_ssid) || ((from_ssid == to_ssid) && (from > to))) {
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if (msgtrigger)
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pr_warning("0.%x.%04x to 0.%x.%04x is not a valid "
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"range for cio_ignore\n", from_ssid, from,
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to_ssid, to);
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return 1;
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}
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while ((from_ssid < to_ssid) || ((from_ssid == to_ssid) &&
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(from <= to))) {
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if (action == add)
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set_bit(from, bl_dev[from_ssid]);
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else
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clear_bit(from, bl_dev[from_ssid]);
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from++;
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if (from > __MAX_SUBCHANNEL) {
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from_ssid++;
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from = 0;
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}
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}
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return 0;
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}
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static int pure_hex(char **cp, unsigned int *val, int min_digit,
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int max_digit, int max_val)
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{
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int diff;
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unsigned int value;
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diff = 0;
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*val = 0;
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while (isxdigit(**cp) && (diff <= max_digit)) {
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if (isdigit(**cp))
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value = **cp - '0';
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else
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value = tolower(**cp) - 'a' + 10;
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*val = *val * 16 + value;
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(*cp)++;
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diff++;
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}
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if ((diff < min_digit) || (diff > max_digit) || (*val > max_val))
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return 1;
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return 0;
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}
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static int parse_busid(char *str, unsigned int *cssid, unsigned int *ssid,
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unsigned int *devno, int msgtrigger)
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{
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char *str_work;
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int val, rc, ret;
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rc = 1;
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if (*str == '\0')
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goto out;
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/* old style */
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str_work = str;
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val = simple_strtoul(str, &str_work, 16);
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if (*str_work == '\0') {
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if (val <= __MAX_SUBCHANNEL) {
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*devno = val;
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*ssid = 0;
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*cssid = 0;
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rc = 0;
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}
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goto out;
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}
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/* new style */
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str_work = str;
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ret = pure_hex(&str_work, cssid, 1, 2, __MAX_CSSID);
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if (ret || (str_work[0] != '.'))
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goto out;
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str_work++;
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ret = pure_hex(&str_work, ssid, 1, 1, __MAX_SSID);
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if (ret || (str_work[0] != '.'))
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goto out;
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str_work++;
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ret = pure_hex(&str_work, devno, 4, 4, __MAX_SUBCHANNEL);
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if (ret || (str_work[0] != '\0'))
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goto out;
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rc = 0;
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out:
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if (rc && msgtrigger)
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pr_warning("%s is not a valid device for the cio_ignore "
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"kernel parameter\n", str);
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return rc;
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}
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static int blacklist_parse_parameters(char *str, range_action action,
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int msgtrigger)
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{
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unsigned int from_cssid, to_cssid, from_ssid, to_ssid, from, to;
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int rc, totalrc;
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char *parm;
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range_action ra;
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totalrc = 0;
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while ((parm = strsep(&str, ","))) {
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rc = 0;
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ra = action;
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if (*parm == '!') {
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if (ra == add)
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ra = free;
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else
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ra = add;
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parm++;
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}
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if (strcmp(parm, "all") == 0) {
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from_cssid = 0;
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from_ssid = 0;
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from = 0;
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to_cssid = __MAX_CSSID;
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to_ssid = __MAX_SSID;
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to = __MAX_SUBCHANNEL;
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} else {
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rc = parse_busid(strsep(&parm, "-"), &from_cssid,
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&from_ssid, &from, msgtrigger);
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if (!rc) {
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if (parm != NULL)
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rc = parse_busid(parm, &to_cssid,
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&to_ssid, &to,
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msgtrigger);
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else {
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to_cssid = from_cssid;
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to_ssid = from_ssid;
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to = from;
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}
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}
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}
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if (!rc) {
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rc = blacklist_range(ra, from_ssid, to_ssid, from, to,
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msgtrigger);
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if (rc)
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totalrc = -EINVAL;
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} else
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totalrc = -EINVAL;
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}
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return totalrc;
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}
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static int __init
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blacklist_setup (char *str)
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{
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CIO_MSG_EVENT(6, "Reading blacklist parameters\n");
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if (blacklist_parse_parameters(str, add, 1))
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return 0;
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return 1;
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}
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__setup ("cio_ignore=", blacklist_setup);
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/* Checking if devices are blacklisted */
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/*
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* Function: is_blacklisted
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* Returns 1 if the given devicenumber can be found in the blacklist,
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* otherwise 0.
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* Used by validate_subchannel()
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*/
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int
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is_blacklisted (int ssid, int devno)
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{
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return test_bit (devno, bl_dev[ssid]);
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}
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#ifdef CONFIG_PROC_FS
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/*
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* Function: blacklist_parse_proc_parameters
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* parse the stuff which is piped to /proc/cio_ignore
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*/
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static int blacklist_parse_proc_parameters(char *buf)
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{
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int rc;
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char *parm;
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parm = strsep(&buf, " ");
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if (strcmp("free", parm) == 0)
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rc = blacklist_parse_parameters(buf, free, 0);
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else if (strcmp("add", parm) == 0)
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rc = blacklist_parse_parameters(buf, add, 0);
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else if (strcmp("purge", parm) == 0)
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return ccw_purge_blacklisted();
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else
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return -EINVAL;
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css_schedule_reprobe();
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return rc;
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}
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/* Iterator struct for all devices. */
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struct ccwdev_iter {
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int devno;
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int ssid;
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int in_range;
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};
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static void *
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cio_ignore_proc_seq_start(struct seq_file *s, loff_t *offset)
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{
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struct ccwdev_iter *iter = s->private;
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if (*offset >= (__MAX_SUBCHANNEL + 1) * (__MAX_SSID + 1))
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return NULL;
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memset(iter, 0, sizeof(*iter));
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iter->ssid = *offset / (__MAX_SUBCHANNEL + 1);
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iter->devno = *offset % (__MAX_SUBCHANNEL + 1);
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return iter;
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}
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static void
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cio_ignore_proc_seq_stop(struct seq_file *s, void *it)
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{
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}
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static void *
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cio_ignore_proc_seq_next(struct seq_file *s, void *it, loff_t *offset)
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{
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struct ccwdev_iter *iter;
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if (*offset >= (__MAX_SUBCHANNEL + 1) * (__MAX_SSID + 1))
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return NULL;
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iter = it;
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if (iter->devno == __MAX_SUBCHANNEL) {
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iter->devno = 0;
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iter->ssid++;
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if (iter->ssid > __MAX_SSID)
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return NULL;
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} else
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iter->devno++;
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(*offset)++;
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return iter;
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}
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static int
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cio_ignore_proc_seq_show(struct seq_file *s, void *it)
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{
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struct ccwdev_iter *iter;
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iter = it;
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if (!is_blacklisted(iter->ssid, iter->devno))
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/* Not blacklisted, nothing to output. */
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return 0;
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if (!iter->in_range) {
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/* First device in range. */
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if ((iter->devno == __MAX_SUBCHANNEL) ||
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!is_blacklisted(iter->ssid, iter->devno + 1))
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/* Singular device. */
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return seq_printf(s, "0.%x.%04x\n",
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iter->ssid, iter->devno);
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iter->in_range = 1;
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return seq_printf(s, "0.%x.%04x-", iter->ssid, iter->devno);
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}
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if ((iter->devno == __MAX_SUBCHANNEL) ||
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!is_blacklisted(iter->ssid, iter->devno + 1)) {
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/* Last device in range. */
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iter->in_range = 0;
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return seq_printf(s, "0.%x.%04x\n", iter->ssid, iter->devno);
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}
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return 0;
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}
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static ssize_t
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cio_ignore_write(struct file *file, const char __user *user_buf,
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size_t user_len, loff_t *offset)
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{
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char *buf;
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ssize_t rc, ret, i;
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if (*offset)
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return -EINVAL;
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if (user_len > 65536)
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user_len = 65536;
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buf = vmalloc (user_len + 1); /* maybe better use the stack? */
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if (buf == NULL)
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return -ENOMEM;
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memset(buf, 0, user_len + 1);
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if (strncpy_from_user (buf, user_buf, user_len) < 0) {
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rc = -EFAULT;
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goto out_free;
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}
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i = user_len - 1;
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while ((i >= 0) && (isspace(buf[i]) || (buf[i] == 0))) {
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buf[i] = '\0';
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i--;
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}
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ret = blacklist_parse_proc_parameters(buf);
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if (ret)
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rc = ret;
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else
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rc = user_len;
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out_free:
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vfree (buf);
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return rc;
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}
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static const struct seq_operations cio_ignore_proc_seq_ops = {
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.start = cio_ignore_proc_seq_start,
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.stop = cio_ignore_proc_seq_stop,
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.next = cio_ignore_proc_seq_next,
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.show = cio_ignore_proc_seq_show,
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};
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static int
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cio_ignore_proc_open(struct inode *inode, struct file *file)
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{
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return seq_open_private(file, &cio_ignore_proc_seq_ops,
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sizeof(struct ccwdev_iter));
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}
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static const struct file_operations cio_ignore_proc_fops = {
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.open = cio_ignore_proc_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release_private,
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.write = cio_ignore_write,
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};
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static int
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cio_ignore_proc_init (void)
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{
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struct proc_dir_entry *entry;
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entry = proc_create("cio_ignore", S_IFREG | S_IRUGO | S_IWUSR, NULL,
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&cio_ignore_proc_fops);
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if (!entry)
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return -ENOENT;
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return 0;
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}
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__initcall (cio_ignore_proc_init);
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#endif /* CONFIG_PROC_FS */
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