diff options
Diffstat (limited to 'kernel/sysctl.c')
| -rw-r--r-- | kernel/sysctl.c | 103 |
1 files changed, 85 insertions, 18 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index e36ae4b15726..ba9ed453c4ed 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -173,6 +173,13 @@ extern int no_unaligned_warning; #endif #ifdef CONFIG_PROC_SYSCTL + +#define SYSCTL_WRITES_LEGACY -1 +#define SYSCTL_WRITES_WARN 0 +#define SYSCTL_WRITES_STRICT 1 + +static int sysctl_writes_strict = SYSCTL_WRITES_WARN; + static int proc_do_cad_pid(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); static int proc_taint(struct ctl_table *table, int write, @@ -195,7 +202,7 @@ static int proc_dostring_coredump(struct ctl_table *table, int write, /* Note: sysrq code uses it's own private copy */ static int __sysrq_enabled = CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE; -static int sysrq_sysctl_handler(ctl_table *table, int write, +static int sysrq_sysctl_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { @@ -495,6 +502,15 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = proc_taint, }, + { + .procname = "sysctl_writes_strict", + .data = &sysctl_writes_strict, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &neg_one, + .extra2 = &one, + }, #endif #ifdef CONFIG_LATENCYTOP { @@ -643,7 +659,7 @@ static struct ctl_table kern_table[] = { .extra2 = &one, }, #endif - +#ifdef CONFIG_UEVENT_HELPER { .procname = "hotplug", .data = &uevent_helper, @@ -651,7 +667,7 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = proc_dostring, }, - +#endif #ifdef CONFIG_CHR_DEV_SG { .procname = "sg-big-buff", @@ -1418,8 +1434,13 @@ static struct ctl_table vm_table[] = { (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL)) { .procname = "vdso_enabled", +#ifdef CONFIG_X86_32 + .data = &vdso32_enabled, + .maxlen = sizeof(vdso32_enabled), +#else .data = &vdso_enabled, .maxlen = sizeof(vdso_enabled), +#endif .mode = 0644, .proc_handler = proc_dointvec, .extra1 = &zero, @@ -1698,8 +1719,8 @@ int __init sysctl_init(void) #ifdef CONFIG_PROC_SYSCTL -static int _proc_do_string(void* data, int maxlen, int write, - void __user *buffer, +static int _proc_do_string(char *data, int maxlen, int write, + char __user *buffer, size_t *lenp, loff_t *ppos) { size_t len; @@ -1712,21 +1733,30 @@ static int _proc_do_string(void* data, int maxlen, int write, } if (write) { - len = 0; + if (sysctl_writes_strict == SYSCTL_WRITES_STRICT) { + /* Only continue writes not past the end of buffer. */ + len = strlen(data); + if (len > maxlen - 1) + len = maxlen - 1; + + if (*ppos > len) + return 0; + len = *ppos; + } else { + /* Start writing from beginning of buffer. */ + len = 0; + } + + *ppos += *lenp; p = buffer; - while (len < *lenp) { + while ((p - buffer) < *lenp && len < maxlen - 1) { if (get_user(c, p++)) return -EFAULT; if (c == 0 || c == '\n') break; - len++; + data[len++] = c; } - if (len >= maxlen) - len = maxlen-1; - if(copy_from_user(data, buffer, len)) - return -EFAULT; - ((char *) data)[len] = 0; - *ppos += *lenp; + data[len] = 0; } else { len = strlen(data); if (len > maxlen) @@ -1743,10 +1773,10 @@ static int _proc_do_string(void* data, int maxlen, int write, if (len > *lenp) len = *lenp; if (len) - if(copy_to_user(buffer, data, len)) + if (copy_to_user(buffer, data, len)) return -EFAULT; if (len < *lenp) { - if(put_user('\n', ((char __user *) buffer) + len)) + if (put_user('\n', buffer + len)) return -EFAULT; len++; } @@ -1756,6 +1786,14 @@ static int _proc_do_string(void* data, int maxlen, int write, return 0; } +static void warn_sysctl_write(struct ctl_table *table) +{ + pr_warn_once("%s wrote to %s when file position was not 0!\n" + "This will not be supported in the future. To silence this\n" + "warning, set kernel.sysctl_writes_strict = -1\n", + current->comm, table->procname); +} + /** * proc_dostring - read a string sysctl * @table: the sysctl table @@ -1776,8 +1814,11 @@ static int _proc_do_string(void* data, int maxlen, int write, int proc_dostring(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { - return _proc_do_string(table->data, table->maxlen, write, - buffer, lenp, ppos); + if (write && *ppos && sysctl_writes_strict == SYSCTL_WRITES_WARN) + warn_sysctl_write(table); + + return _proc_do_string((char *)(table->data), table->maxlen, write, + (char __user *)buffer, lenp, ppos); } static size_t proc_skip_spaces(char **buf) @@ -1951,6 +1992,18 @@ static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table, conv = do_proc_dointvec_conv; if (write) { + if (*ppos) { + switch (sysctl_writes_strict) { + case SYSCTL_WRITES_STRICT: + goto out; + case SYSCTL_WRITES_WARN: + warn_sysctl_write(table); + break; + default: + break; + } + } + if (left > PAGE_SIZE - 1) left = PAGE_SIZE - 1; page = __get_free_page(GFP_TEMPORARY); @@ -2008,6 +2061,7 @@ free: return err ? : -EINVAL; } *lenp -= left; +out: *ppos += *lenp; return err; } @@ -2200,6 +2254,18 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int left = *lenp; if (write) { + if (*ppos) { + switch (sysctl_writes_strict) { + case SYSCTL_WRITES_STRICT: + goto out; + case SYSCTL_WRITES_WARN: + warn_sysctl_write(table); + break; + default: + break; + } + } + if (left > PAGE_SIZE - 1) left = PAGE_SIZE - 1; page = __get_free_page(GFP_TEMPORARY); @@ -2255,6 +2321,7 @@ free: return err ? : -EINVAL; } *lenp -= left; +out: *ppos += *lenp; return err; } |