diff options
author | Christoph Hellwig <hch@lst.de> | 2020-04-24 09:43:38 +0300 |
---|---|---|
committer | Al Viro <viro@zeniv.linux.org.uk> | 2020-04-27 09:07:40 +0300 |
commit | 32927393dc1ccd60fb2bdc05b9e8e88753761469 (patch) | |
tree | c488a5564cdde7594c953219a98e22fb4865c812 /kernel/sysctl.c | |
parent | f461d2dcd511c020a26d4d791fae595c65ed09b6 (diff) |
sysctl: pass kernel pointers to ->proc_handler
Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from userspace in common code. This also means that the strings are
always NUL-terminated by the common code, making the API a little bit
safer.
As most handler just pass through the data to one of the common handlers
a lot of the changes are mechnical.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'kernel/sysctl.c')
-rw-r--r-- | kernel/sysctl.c | 239 |
1 files changed, 91 insertions, 148 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 3fafca3ced98..e961286d0e14 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -208,12 +208,10 @@ static int max_extfrag_threshold = 1000; #ifdef CONFIG_PROC_SYSCTL static int _proc_do_string(char *data, int maxlen, int write, - char __user *buffer, - size_t *lenp, loff_t *ppos) + char *buffer, size_t *lenp, loff_t *ppos) { size_t len; - char __user *p; - char c; + char c, *p; if (!data || !maxlen || !*lenp) { *lenp = 0; @@ -238,8 +236,7 @@ static int _proc_do_string(char *data, int maxlen, int write, *ppos += *lenp; p = buffer; while ((p - buffer) < *lenp && len < maxlen - 1) { - if (get_user(c, p++)) - return -EFAULT; + c = *(p++); if (c == 0 || c == '\n') break; data[len++] = c; @@ -261,11 +258,9 @@ static int _proc_do_string(char *data, int maxlen, int write, if (len > *lenp) len = *lenp; if (len) - if (copy_to_user(buffer, data, len)) - return -EFAULT; + memcpy(buffer, data, len); if (len < *lenp) { - if (put_user('\n', buffer + len)) - return -EFAULT; + buffer[len] = '\n'; len++; } *lenp = len; @@ -326,13 +321,13 @@ static bool proc_first_pos_non_zero_ignore(loff_t *ppos, * Returns 0 on success. */ int proc_dostring(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { if (write) proc_first_pos_non_zero_ignore(ppos, table); - return _proc_do_string((char *)(table->data), table->maxlen, write, - (char __user *)buffer, lenp, ppos); + return _proc_do_string(table->data, table->maxlen, write, buffer, lenp, + ppos); } static size_t proc_skip_spaces(char **buf) @@ -463,11 +458,10 @@ static int proc_get_long(char **buf, size_t *size, * @val: the integer to be converted * @neg: sign of the number, %TRUE for negative * - * In case of success %0 is returned and @buf and @size are updated with - * the amount of bytes written. + * In case of success @buf and @size are updated with the amount of bytes + * written. */ -static int proc_put_long(void __user **buf, size_t *size, unsigned long val, - bool neg) +static void proc_put_long(void **buf, size_t *size, unsigned long val, bool neg) { int len; char tmp[TMPBUFLEN], *p = tmp; @@ -476,24 +470,22 @@ static int proc_put_long(void __user **buf, size_t *size, unsigned long val, len = strlen(tmp); if (len > *size) len = *size; - if (copy_to_user(*buf, tmp, len)) - return -EFAULT; + memcpy(*buf, tmp, len); *size -= len; *buf += len; - return 0; } #undef TMPBUFLEN -static int proc_put_char(void __user **buf, size_t *size, char c) +static void proc_put_char(void **buf, size_t *size, char c) { if (*size) { - char __user **buffer = (char __user **)buf; - if (put_user(c, *buffer)) - return -EFAULT; - (*size)--, (*buffer)++; + char **buffer = (char **)buf; + **buffer = c; + + (*size)--; + (*buffer)++; *buf = *buffer; } - return 0; } static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp, @@ -541,7 +533,7 @@ static int do_proc_douintvec_conv(unsigned long *lvalp, static const char proc_wspace_sep[] = { ' ', '\t', '\n' }; static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table, - int write, void __user *buffer, + int write, void *buffer, size_t *lenp, loff_t *ppos, int (*conv)(bool *negp, unsigned long *lvalp, int *valp, int write, void *data), @@ -549,7 +541,7 @@ static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table, { int *i, vleft, first = 1, err = 0; size_t left; - char *kbuf = NULL, *p; + char *p; if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) { *lenp = 0; @@ -569,9 +561,7 @@ static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table, if (left > PAGE_SIZE - 1) left = PAGE_SIZE - 1; - p = kbuf = memdup_user_nul(buffer, left); - if (IS_ERR(kbuf)) - return PTR_ERR(kbuf); + p = buffer; } for (; left && vleft--; i++, first=0) { @@ -598,24 +588,17 @@ static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table, break; } if (!first) - err = proc_put_char(&buffer, &left, '\t'); - if (err) - break; - err = proc_put_long(&buffer, &left, lval, neg); - if (err) - break; + proc_put_char(&buffer, &left, '\t'); + proc_put_long(&buffer, &left, lval, neg); } } if (!write && !first && left && !err) - err = proc_put_char(&buffer, &left, '\n'); + proc_put_char(&buffer, &left, '\n'); if (write && !err && left) left -= proc_skip_spaces(&p); - if (write) { - kfree(kbuf); - if (first) - return err ? : -EINVAL; - } + if (write && first) + return err ? : -EINVAL; *lenp -= left; out: *ppos += *lenp; @@ -623,7 +606,7 @@ out: } static int do_proc_dointvec(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos, + void *buffer, size_t *lenp, loff_t *ppos, int (*conv)(bool *negp, unsigned long *lvalp, int *valp, int write, void *data), void *data) @@ -634,7 +617,7 @@ static int do_proc_dointvec(struct ctl_table *table, int write, static int do_proc_douintvec_w(unsigned int *tbl_data, struct ctl_table *table, - void __user *buffer, + void *buffer, size_t *lenp, loff_t *ppos, int (*conv)(unsigned long *lvalp, unsigned int *valp, @@ -645,7 +628,7 @@ static int do_proc_douintvec_w(unsigned int *tbl_data, int err = 0; size_t left; bool neg; - char *kbuf = NULL, *p; + char *p = buffer; left = *lenp; @@ -655,10 +638,6 @@ static int do_proc_douintvec_w(unsigned int *tbl_data, if (left > PAGE_SIZE - 1) left = PAGE_SIZE - 1; - p = kbuf = memdup_user_nul(buffer, left); - if (IS_ERR(kbuf)) - return -EINVAL; - left -= proc_skip_spaces(&p); if (!left) { err = -EINVAL; @@ -682,7 +661,6 @@ static int do_proc_douintvec_w(unsigned int *tbl_data, left -= proc_skip_spaces(&p); out_free: - kfree(kbuf); if (err) return -EINVAL; @@ -694,7 +672,7 @@ bail_early: return err; } -static int do_proc_douintvec_r(unsigned int *tbl_data, void __user *buffer, +static int do_proc_douintvec_r(unsigned int *tbl_data, void *buffer, size_t *lenp, loff_t *ppos, int (*conv)(unsigned long *lvalp, unsigned int *valp, @@ -712,11 +690,11 @@ static int do_proc_douintvec_r(unsigned int *tbl_data, void __user *buffer, goto out; } - err = proc_put_long(&buffer, &left, lval, false); - if (err || !left) + proc_put_long(&buffer, &left, lval, false); + if (!left) goto out; - err = proc_put_char(&buffer, &left, '\n'); + proc_put_char(&buffer, &left, '\n'); out: *lenp -= left; @@ -726,7 +704,7 @@ out: } static int __do_proc_douintvec(void *tbl_data, struct ctl_table *table, - int write, void __user *buffer, + int write, void *buffer, size_t *lenp, loff_t *ppos, int (*conv)(unsigned long *lvalp, unsigned int *valp, @@ -762,7 +740,7 @@ static int __do_proc_douintvec(void *tbl_data, struct ctl_table *table, } static int do_proc_douintvec(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos, + void *buffer, size_t *lenp, loff_t *ppos, int (*conv)(unsigned long *lvalp, unsigned int *valp, int write, void *data), @@ -785,16 +763,15 @@ static int do_proc_douintvec(struct ctl_table *table, int write, * * Returns 0 on success. */ -int proc_dointvec(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) +int proc_dointvec(struct ctl_table *table, int write, void *buffer, + size_t *lenp, loff_t *ppos) { return do_proc_dointvec(table, write, buffer, lenp, ppos, NULL, NULL); } #ifdef CONFIG_COMPACTION static int proc_dointvec_minmax_warn_RT_change(struct ctl_table *table, - int write, void __user *buffer, - size_t *lenp, loff_t *ppos) + int write, void *buffer, size_t *lenp, loff_t *ppos) { int ret, old; @@ -826,8 +803,8 @@ static int proc_dointvec_minmax_warn_RT_change(struct ctl_table *table, * * Returns 0 on success. */ -int proc_douintvec(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) +int proc_douintvec(struct ctl_table *table, int write, void *buffer, + size_t *lenp, loff_t *ppos) { return do_proc_douintvec(table, write, buffer, lenp, ppos, do_proc_douintvec_conv, NULL); @@ -838,7 +815,7 @@ int proc_douintvec(struct ctl_table *table, int write, * This means we can safely use a temporary. */ static int proc_taint(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { struct ctl_table t; unsigned long tmptaint = get_taint(); @@ -870,7 +847,7 @@ static int proc_taint(struct ctl_table *table, int write, #ifdef CONFIG_PRINTK static int proc_dointvec_minmax_sysadmin(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { if (write && !capable(CAP_SYS_ADMIN)) return -EPERM; @@ -936,7 +913,7 @@ static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp, * Returns 0 on success or -EINVAL on write when the range check fails. */ int proc_dointvec_minmax(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { struct do_proc_dointvec_minmax_conv_param param = { .min = (int *) table->extra1, @@ -1005,7 +982,7 @@ static int do_proc_douintvec_minmax_conv(unsigned long *lvalp, * Returns 0 on success or -ERANGE on write when the range check fails. */ int proc_douintvec_minmax(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { struct do_proc_douintvec_minmax_conv_param param = { .min = (unsigned int *) table->extra1, @@ -1036,7 +1013,7 @@ static int do_proc_dopipe_max_size_conv(unsigned long *lvalp, } static int proc_dopipe_max_size(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { return do_proc_douintvec(table, write, buffer, lenp, ppos, do_proc_dopipe_max_size_conv, NULL); @@ -1057,7 +1034,7 @@ static void validate_coredump_safety(void) } static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { int error = proc_dointvec_minmax(table, write, buffer, lenp, ppos); if (!error) @@ -1067,7 +1044,7 @@ static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write, #ifdef CONFIG_COREDUMP static int proc_dostring_coredump(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { int error = proc_dostring(table, write, buffer, lenp, ppos); if (!error) @@ -1078,7 +1055,7 @@ static int proc_dostring_coredump(struct ctl_table *table, int write, #ifdef CONFIG_MAGIC_SYSRQ static int sysrq_sysctl_handler(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { int tmp, ret; @@ -1096,16 +1073,14 @@ static int sysrq_sysctl_handler(struct ctl_table *table, int write, } #endif -static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write, - void __user *buffer, - size_t *lenp, loff_t *ppos, - unsigned long convmul, - unsigned long convdiv) +static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, + int write, void *buffer, size_t *lenp, loff_t *ppos, + unsigned long convmul, unsigned long convdiv) { unsigned long *i, *min, *max; int vleft, first = 1, err = 0; size_t left; - char *kbuf = NULL, *p; + char *p; if (!data || !table->maxlen || !*lenp || (*ppos && !write)) { *lenp = 0; @@ -1124,9 +1099,7 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int if (left > PAGE_SIZE - 1) left = PAGE_SIZE - 1; - p = kbuf = memdup_user_nul(buffer, left); - if (IS_ERR(kbuf)) - return PTR_ERR(kbuf); + p = buffer; } for (; left && vleft--; i++, first = 0) { @@ -1154,26 +1127,18 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int *i = val; } else { val = convdiv * (*i) / convmul; - if (!first) { - err = proc_put_char(&buffer, &left, '\t'); - if (err) - break; - } - err = proc_put_long(&buffer, &left, val, false); - if (err) - break; + if (!first) + proc_put_char(&buffer, &left, '\t'); + proc_put_long(&buffer, &left, val, false); } } if (!write && !first && left && !err) - err = proc_put_char(&buffer, &left, '\n'); + proc_put_char(&buffer, &left, '\n'); if (write && !err) left -= proc_skip_spaces(&p); - if (write) { - kfree(kbuf); - if (first) - return err ? : -EINVAL; - } + if (write && first) + return err ? : -EINVAL; *lenp -= left; out: *ppos += *lenp; @@ -1181,10 +1146,8 @@ out: } static int do_proc_doulongvec_minmax(struct ctl_table *table, int write, - void __user *buffer, - size_t *lenp, loff_t *ppos, - unsigned long convmul, - unsigned long convdiv) + void *buffer, size_t *lenp, loff_t *ppos, unsigned long convmul, + unsigned long convdiv) { return __do_proc_doulongvec_minmax(table->data, table, write, buffer, lenp, ppos, convmul, convdiv); @@ -1207,7 +1170,7 @@ static int do_proc_doulongvec_minmax(struct ctl_table *table, int write, * Returns 0 on success. */ int proc_doulongvec_minmax(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { return do_proc_doulongvec_minmax(table, write, buffer, lenp, ppos, 1l, 1l); } @@ -1230,8 +1193,7 @@ int proc_doulongvec_minmax(struct ctl_table *table, int write, * Returns 0 on success. */ int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write, - void __user *buffer, - size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { return do_proc_doulongvec_minmax(table, write, buffer, lenp, ppos, HZ, 1000l); @@ -1325,7 +1287,7 @@ static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp, * Returns 0 on success. */ int proc_dointvec_jiffies(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { return do_proc_dointvec(table,write,buffer,lenp,ppos, do_proc_dointvec_jiffies_conv,NULL); @@ -1347,7 +1309,7 @@ int proc_dointvec_jiffies(struct ctl_table *table, int write, * Returns 0 on success. */ int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { return do_proc_dointvec(table,write,buffer,lenp,ppos, do_proc_dointvec_userhz_jiffies_conv,NULL); @@ -1369,15 +1331,15 @@ int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write, * * Returns 0 on success. */ -int proc_dointvec_ms_jiffies(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) +int proc_dointvec_ms_jiffies(struct ctl_table *table, int write, void *buffer, + size_t *lenp, loff_t *ppos) { return do_proc_dointvec(table, write, buffer, lenp, ppos, do_proc_dointvec_ms_jiffies_conv, NULL); } -static int proc_do_cad_pid(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) +static int proc_do_cad_pid(struct ctl_table *table, int write, void *buffer, + size_t *lenp, loff_t *ppos) { struct pid *new_pid; pid_t tmp; @@ -1416,7 +1378,7 @@ static int proc_do_cad_pid(struct ctl_table *table, int write, * Returns 0 on success. */ int proc_do_large_bitmap(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { int err = 0; bool first = 1; @@ -1432,7 +1394,7 @@ int proc_do_large_bitmap(struct ctl_table *table, int write, } if (write) { - char *kbuf, *p; + char *p = buffer; size_t skipped = 0; if (left > PAGE_SIZE - 1) { @@ -1441,15 +1403,9 @@ int proc_do_large_bitmap(struct ctl_table *table, int write, skipped = *lenp - left; } - p = kbuf = memdup_user_nul(buffer, left); - if (IS_ERR(kbuf)) - return PTR_ERR(kbuf); - tmp_bitmap = bitmap_zalloc(bitmap_len, GFP_KERNEL); - if (!tmp_bitmap) { - kfree(kbuf); + if (!tmp_bitmap) return -ENOMEM; - } proc_skip_char(&p, &left, '\n'); while (!err && left) { unsigned long val_a, val_b; @@ -1513,7 +1469,6 @@ int proc_do_large_bitmap(struct ctl_table *table, int write, first = 0; proc_skip_char(&p, &left, '\n'); } - kfree(kbuf); left += skipped; } else { unsigned long bit_a, bit_b = 0; @@ -1525,27 +1480,17 @@ int proc_do_large_bitmap(struct ctl_table *table, int write, bit_b = find_next_zero_bit(bitmap, bitmap_len, bit_a + 1) - 1; - if (!first) { - err = proc_put_char(&buffer, &left, ','); - if (err) - break; - } - err = proc_put_long(&buffer, &left, bit_a, false); - if (err) - break; + if (!first) + proc_put_char(&buffer, &left, ','); + proc_put_long(&buffer, &left, bit_a, false); if (bit_a != bit_b) { - err = proc_put_char(&buffer, &left, '-'); - if (err) - break; - err = proc_put_long(&buffer, &left, bit_b, false); - if (err) - break; + proc_put_char(&buffer, &left, '-'); + proc_put_long(&buffer, &left, bit_b, false); } first = 0; bit_b++; } - if (!err) - err = proc_put_char(&buffer, &left, '\n'); + proc_put_char(&buffer, &left, '\n'); } if (!err) { @@ -1566,68 +1511,67 @@ int proc_do_large_bitmap(struct ctl_table *table, int write, #else /* CONFIG_PROC_SYSCTL */ int proc_dostring(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { return -ENOSYS; } int proc_dointvec(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { return -ENOSYS; } int proc_douintvec(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { return -ENOSYS; } int proc_dointvec_minmax(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { return -ENOSYS; } int proc_douintvec_minmax(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { return -ENOSYS; } int proc_dointvec_jiffies(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { return -ENOSYS; } int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { return -ENOSYS; } int proc_dointvec_ms_jiffies(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { return -ENOSYS; } int proc_doulongvec_minmax(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { return -ENOSYS; } int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write, - void __user *buffer, - size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { - return -ENOSYS; + return -ENOSYS; } int proc_do_large_bitmap(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { return -ENOSYS; } @@ -1636,8 +1580,7 @@ int proc_do_large_bitmap(struct ctl_table *table, int write, #if defined(CONFIG_SYSCTL) int proc_do_static_key(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, - loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { struct static_key *key = (struct static_key *)table->data; static DEFINE_MUTEX(static_key_mutex); |