Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757720Ab0DIKLa (ORCPT ); Fri, 9 Apr 2010 06:11:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49713 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757624Ab0DIKLV (ORCPT ); Fri, 9 Apr 2010 06:11:21 -0400 Date: Fri, 9 Apr 2010 06:11:04 -0400 From: Amerigo Wang To: linux-kernel@vger.kernel.org Cc: Octavian Purdila , Eric Dumazet , netdev@vger.kernel.org, Neil Horman , Amerigo Wang , David Miller , ebiederm@xmission.com Message-Id: <20100409101452.5051.74050.sendpatchset@localhost.localdomain> In-Reply-To: <20100409101442.5051.99812.sendpatchset@localhost.localdomain> References: <20100409101442.5051.99812.sendpatchset@localhost.localdomain> Subject: [Patch 1/3] sysctl: refactor integer handling proc code Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 13219 Lines: 535 From: Octavian Purdila As we are about to add another integer handling proc function a little bit of cleanup is in order: add a few helper functions to improve code readability and decrease code duplication. In the process a bug is also fixed: if the user specifies a number with more then 20 digits it will be interpreted as two integers (e.g. 10000...13 will be interpreted as 100.... and 13). Behavior for EFAULT handling was changed as well. Previous to this patch, when an EFAULT error occurred in the middle of a write operation, although some of the elements were set, that was not acknowledged to the user (by shorting the write and returning the number of bytes accepted). EFAULT is now treated just like any other errors by acknowledging the amount of bytes accepted. Signed-off-by: Octavian Purdila Signed-off-by: WANG Cong Cc: Eric W. Biederman --- Index: linux-2.6/kernel/sysctl.c =================================================================== --- linux-2.6.orig/kernel/sysctl.c +++ linux-2.6/kernel/sysctl.c @@ -2040,8 +2040,148 @@ int proc_dostring(struct ctl_table *tabl buffer, lenp, ppos); } +static int proc_skip_wspace(char __user **buf, size_t *size) +{ + char c; + + while (*size) { + if (get_user(c, *buf)) + return -EFAULT; + if (!isspace(c)) + break; + (*size)--; + (*buf)++; + } + + return 0; +} + +static bool isanyof(char c, const char *v, unsigned len) +{ + int i; + + if (!len) + return false; + + for (i = 0; i < len; i++) + if (c == v[i]) + break; + if (i == len) + return false; + + return true; +} + +#define TMPBUFLEN 22 +/** + * proc_get_ulong - reads an ASCII formated integer from a user buffer + * + * @buf - user buffer + * @size - size of the user buffer + * @val - this is where the number will be stored + * @neg - set to %TRUE if number is negative + * @perm_tr - a vector which contains the allowed trailers + * @perm_tr_len - size of the perm_tr vector + * @tr - pointer to store the trailer character + * + * In case of success 0 is returned and buf and size are updated with + * the amount of bytes read. If tr is non NULL and a trailing + * character exist (size is non zero after returning from this + * function) tr is updated with the trailing character. + */ +static int proc_get_ulong(char __user **buf, size_t *size, + unsigned long *val, bool *neg, + const char *perm_tr, unsigned perm_tr_len, char *tr) +{ + int len; + char *p, tmp[TMPBUFLEN]; + + if (!*size) + return -EINVAL; + + len = *size; + if (len > TMPBUFLEN-1) + len = TMPBUFLEN-1; + + if (copy_from_user(tmp, *buf, len)) + return -EFAULT; + + tmp[len] = 0; + p = tmp; + if (*p == '-' && *size > 1) { + *neg = 1; + p++; + } else + *neg = 0; + if (!isdigit(*p)) + return -EINVAL; + + *val = simple_strtoul(p, &p, 0); + + len = p - tmp; + + /* We don't know if the next char is whitespace thus we may accept + * invalid integers (e.g. 1234...a) or two integers instead of one + * (e.g. 123...1). So lets not allow such large numbers. */ + if (len == TMPBUFLEN - 1) + return -EINVAL; + + if (len < *size && perm_tr_len && !isanyof(*p, perm_tr, perm_tr_len)) + return -EINVAL; + + if (tr && (len < *size)) + *tr = *p; + + *buf += len; + *size -= len; + + return 0; +} + +/** + * proc_put_ulong - coverts an integer to a decimal ASCII formated string + * + * @buf - the user buffer + * @size - the size of the user buffer + * @val - the integer to be converted + * @neg - sign of the number, %TRUE for negative + * @first - if %FALSE will insert a separator character before the number + * @separator - the separator character + * + * In case of success 0 is returned and buf and size are updated with + * the amount of bytes read. + */ +static int proc_put_ulong(char __user **buf, size_t *size, unsigned long val, + bool neg, bool first, char separator) +{ + int len; + char tmp[TMPBUFLEN], *p = tmp; + + if (!first) + *p++ = separator; + sprintf(p, "%s%lu", neg ? "-" : "", val); + len = strlen(tmp); + if (len > *size) + len = *size; + if (copy_to_user(*buf, tmp, len)) + return -EFAULT; + *size -= len; + *buf += len; + return 0; +} +#undef TMPBUFLEN + +static int proc_put_char(char __user **buf, size_t *size, char c) +{ + if (*size) { + if (put_user(c, *buf)) + return -EFAULT; + (*size)--, (*buf)++; + } + return 0; +} -static int do_proc_dointvec_conv(int *negp, unsigned long *lvalp, +static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp, int *valp, int write, void *data) { @@ -2050,7 +2190,7 @@ static int do_proc_dointvec_conv(int *ne } else { int val = *valp; if (val < 0) { - *negp = -1; + *negp = 1; *lvalp = (unsigned long)-val; } else { *negp = 0; @@ -2060,20 +2200,18 @@ static int do_proc_dointvec_conv(int *ne return 0; } +static const char proc_wspace_sep[] = { ' ', '\t', '\n', 0 }; + static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table, - int write, void __user *buffer, + int write, void __user *_buffer, size_t *lenp, loff_t *ppos, - int (*conv)(int *negp, unsigned long *lvalp, int *valp, + int (*conv)(bool *negp, unsigned long *lvalp, int *valp, int write, void *data), void *data) { -#define TMPBUFLEN 21 - int *i, vleft, first = 1, neg; - unsigned long lval; - size_t left, len; - - char buf[TMPBUFLEN], *p; - char __user *s = buffer; + int *i, vleft, first = 1, err = 0; + size_t left; + char __user *buffer = (char __user *) _buffer; if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) { @@ -2089,88 +2227,48 @@ static int __do_proc_dointvec(void *tbl_ conv = do_proc_dointvec_conv; for (; left && vleft--; i++, first=0) { - if (write) { - while (left) { - char c; - if (get_user(c, s)) - return -EFAULT; - if (!isspace(c)) - break; - left--; - s++; - } - if (!left) - break; - neg = 0; - len = left; - if (len > sizeof(buf) - 1) - len = sizeof(buf) - 1; - if (copy_from_user(buf, s, len)) - return -EFAULT; - buf[len] = 0; - p = buf; - if (*p == '-' && left > 1) { - neg = 1; - p++; - } - if (*p < '0' || *p > '9') - break; - - lval = simple_strtoul(p, &p, 0); + unsigned long lval; + bool neg; - len = p-buf; - if ((len < left) && *p && !isspace(*p)) + if (write) { + err = proc_skip_wspace(&buffer, &left); + if (err) + return err; + err = proc_get_ulong(&buffer, &left, &lval, &neg, + proc_wspace_sep, + sizeof(proc_wspace_sep), NULL); + if (err) break; - s += len; - left -= len; - - if (conv(&neg, &lval, i, 1, data)) + if (conv(&neg, &lval, i, 1, data)) { + err = -EINVAL; break; + } } else { - p = buf; - if (!first) - *p++ = '\t'; - - if (conv(&neg, &lval, i, 0, data)) + if (conv(&neg, &lval, i, 0, data)) { + err = -EINVAL; break; - - sprintf(p, "%s%lu", neg ? "-" : "", lval); - len = strlen(buf); - if (len > left) - len = left; - if(copy_to_user(s, buf, len)) - return -EFAULT; - left -= len; - s += len; - } - } - - if (!write && !first && left) { - if(put_user('\n', s)) - return -EFAULT; - left--, s++; - } - if (write) { - while (left) { - char c; - if (get_user(c, s++)) - return -EFAULT; - if (!isspace(c)) + } + err = proc_put_ulong(&buffer, &left, lval, neg, first, + '\t'); + if (err) break; - left--; } } + + if (!write && !first && left && !err) + err = proc_put_char(&buffer, &left, '\n'); + if (write && !err) + err = proc_skip_wspace(&buffer, &left); if (write && first) - return -EINVAL; + return err ? : -EINVAL; *lenp -= left; *ppos += *lenp; return 0; -#undef TMPBUFLEN } static int do_proc_dointvec(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos, - int (*conv)(int *negp, unsigned long *lvalp, int *valp, + int (*conv)(bool *negp, unsigned long *lvalp, int *valp, int write, void *data), void *data) { @@ -2238,8 +2336,8 @@ struct do_proc_dointvec_minmax_conv_para int *max; }; -static int do_proc_dointvec_minmax_conv(int *negp, unsigned long *lvalp, - int *valp, +static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp, + int *valp, int write, void *data) { struct do_proc_dointvec_minmax_conv_param *param = data; @@ -2252,7 +2350,7 @@ static int do_proc_dointvec_minmax_conv( } else { int val = *valp; if (val < 0) { - *negp = -1; + *negp = 1; *lvalp = (unsigned long)-val; } else { *negp = 0; @@ -2290,17 +2388,15 @@ int proc_dointvec_minmax(struct ctl_tabl } static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write, - void __user *buffer, + void __user *_buffer, size_t *lenp, loff_t *ppos, unsigned long convmul, unsigned long convdiv) { -#define TMPBUFLEN 21 - unsigned long *i, *min, *max, val; - int vleft, first=1, neg; - size_t len, left; - char buf[TMPBUFLEN], *p; - char __user *s = buffer; + unsigned long *i, *min, *max; + int vleft, first = 1, err = 0; + size_t left; + char __user *buffer = (char __user *) _buffer; if (!data || !table->maxlen || !*lenp || (*ppos && !write)) { @@ -2315,82 +2411,42 @@ static int __do_proc_doulongvec_minmax(v left = *lenp; for (; left && vleft--; i++, min++, max++, first=0) { + unsigned long val; + if (write) { - while (left) { - char c; - if (get_user(c, s)) - return -EFAULT; - if (!isspace(c)) - break; - left--; - s++; - } - if (!left) - break; - neg = 0; - len = left; - if (len > TMPBUFLEN-1) - len = TMPBUFLEN-1; - if (copy_from_user(buf, s, len)) - return -EFAULT; - buf[len] = 0; - p = buf; - if (*p == '-' && left > 1) { - neg = 1; - p++; - } - if (*p < '0' || *p > '9') - break; - val = simple_strtoul(p, &p, 0) * convmul / convdiv ; - len = p-buf; - if ((len < left) && *p && !isspace(*p)) + bool neg; + + err = proc_skip_wspace(&buffer, &left); + if (err) + return err; + err = proc_get_ulong(&buffer, &left, &val, &neg, + proc_wspace_sep, + sizeof(proc_wspace_sep), NULL); + if (err) break; if (neg) - val = -val; - s += len; - left -= len; - - if(neg) continue; if ((min && val < *min) || (max && val > *max)) continue; *i = val; } else { - p = buf; - if (!first) - *p++ = '\t'; - sprintf(p, "%lu", convdiv * (*i) / convmul); - len = strlen(buf); - if (len > left) - len = left; - if(copy_to_user(s, buf, len)) - return -EFAULT; - left -= len; - s += len; - } - } - - if (!write && !first && left) { - if(put_user('\n', s)) - return -EFAULT; - left--, s++; - } - if (write) { - while (left) { - char c; - if (get_user(c, s++)) - return -EFAULT; - if (!isspace(c)) + val = convdiv * (*i) / convmul; + err = proc_put_ulong(&buffer, &left, val, 0, first, + '\t'); + if (err) break; - left--; } } + + if (!write && !first && left && !err) + err = proc_put_char(&buffer, &left, '\n'); + if (write && !err) + err = proc_skip_wspace(&buffer, &left); if (write && first) - return -EINVAL; + return err ? : -EINVAL; *lenp -= left; *ppos += *lenp; return 0; -#undef TMPBUFLEN } static int do_proc_doulongvec_minmax(struct ctl_table *table, int write, @@ -2451,7 +2507,7 @@ int proc_doulongvec_ms_jiffies_minmax(st } -static int do_proc_dointvec_jiffies_conv(int *negp, unsigned long *lvalp, +static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp, int *valp, int write, void *data) { @@ -2463,7 +2519,7 @@ static int do_proc_dointvec_jiffies_conv int val = *valp; unsigned long lval; if (val < 0) { - *negp = -1; + *negp = 1; lval = (unsigned long)-val; } else { *negp = 0; @@ -2474,7 +2530,7 @@ static int do_proc_dointvec_jiffies_conv return 0; } -static int do_proc_dointvec_userhz_jiffies_conv(int *negp, unsigned long *lvalp, +static int do_proc_dointvec_userhz_jiffies_conv(bool *negp, unsigned long *lvalp, int *valp, int write, void *data) { @@ -2486,7 +2542,7 @@ static int do_proc_dointvec_userhz_jiffi int val = *valp; unsigned long lval; if (val < 0) { - *negp = -1; + *negp = 1; lval = (unsigned long)-val; } else { *negp = 0; @@ -2497,7 +2553,7 @@ static int do_proc_dointvec_userhz_jiffi return 0; } -static int do_proc_dointvec_ms_jiffies_conv(int *negp, unsigned long *lvalp, +static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp, int *valp, int write, void *data) { @@ -2507,7 +2563,7 @@ static int do_proc_dointvec_ms_jiffies_c int val = *valp; unsigned long lval; if (val < 0) { - *negp = -1; + *negp = 1; lval = (unsigned long)-val; } else { *negp = 0; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/