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-rw-r--r--lib/vsprintf.c214
1 files changed, 161 insertions, 53 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 739a36366b7..6fe2c84eb05 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -26,6 +26,8 @@
#include <linux/math64.h>
#include <linux/uaccess.h>
#include <linux/ioport.h>
+#include <linux/dcache.h>
+#include <linux/cred.h>
#include <net/addrconf.h>
#include <asm/page.h> /* for PAGE_SIZE */
@@ -362,7 +364,6 @@ enum format_type {
FORMAT_TYPE_SHORT,
FORMAT_TYPE_UINT,
FORMAT_TYPE_INT,
- FORMAT_TYPE_NRCHARS,
FORMAT_TYPE_SIZE_T,
FORMAT_TYPE_PTRDIFF
};
@@ -532,6 +533,81 @@ char *string(char *buf, char *end, const char *s, struct printf_spec spec)
return buf;
}
+static void widen(char *buf, char *end, unsigned len, unsigned spaces)
+{
+ size_t size;
+ if (buf >= end) /* nowhere to put anything */
+ return;
+ size = end - buf;
+ if (size <= spaces) {
+ memset(buf, ' ', size);
+ return;
+ }
+ if (len) {
+ if (len > size - spaces)
+ len = size - spaces;
+ memmove(buf + spaces, buf, len);
+ }
+ memset(buf, ' ', spaces);
+}
+
+static noinline_for_stack
+char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_spec spec,
+ const char *fmt)
+{
+ const char *array[4], *s;
+ const struct dentry *p;
+ int depth;
+ int i, n;
+
+ switch (fmt[1]) {
+ case '2': case '3': case '4':
+ depth = fmt[1] - '0';
+ break;
+ default:
+ depth = 1;
+ }
+
+ rcu_read_lock();
+ for (i = 0; i < depth; i++, d = p) {
+ p = ACCESS_ONCE(d->d_parent);
+ array[i] = ACCESS_ONCE(d->d_name.name);
+ if (p == d) {
+ if (i)
+ array[i] = "";
+ i++;
+ break;
+ }
+ }
+ s = array[--i];
+ for (n = 0; n != spec.precision; n++, buf++) {
+ char c = *s++;
+ if (!c) {
+ if (!i)
+ break;
+ c = '/';
+ s = array[--i];
+ }
+ if (buf < end)
+ *buf = c;
+ }
+ rcu_read_unlock();
+ if (n < spec.field_width) {
+ /* we want to pad the sucker */
+ unsigned spaces = spec.field_width - n;
+ if (!(spec.flags & LEFT)) {
+ widen(buf - n, end, n, spaces);
+ return buf + spaces;
+ }
+ while (spaces--) {
+ if (buf < end)
+ *buf = ' ';
+ ++buf;
+ }
+ }
+ return buf;
+}
+
static noinline_for_stack
char *symbol_string(char *buf, char *end, void *ptr,
struct printf_spec spec, const char *fmt)
@@ -642,10 +718,15 @@ char *resource_string(char *buf, char *end, struct resource *res,
specp = &mem_spec;
decode = 0;
}
- p = number(p, pend, res->start, *specp);
- if (res->start != res->end) {
- *p++ = '-';
- p = number(p, pend, res->end, *specp);
+ if (decode && res->flags & IORESOURCE_UNSET) {
+ p = string(p, pend, "size ", str_spec);
+ p = number(p, pend, resource_size(res), *specp);
+ } else {
+ p = number(p, pend, res->start, *specp);
+ if (res->start != res->end) {
+ *p++ = '-';
+ p = number(p, pend, res->end, *specp);
+ }
}
if (decode) {
if (res->flags & IORESOURCE_MEM_64)
@@ -1078,6 +1159,30 @@ char *netdev_feature_string(char *buf, char *end, const u8 *addr,
return number(buf, end, *(const netdev_features_t *)addr, spec);
}
+static noinline_for_stack
+char *address_val(char *buf, char *end, const void *addr,
+ struct printf_spec spec, const char *fmt)
+{
+ unsigned long long num;
+
+ spec.flags |= SPECIAL | SMALL | ZEROPAD;
+ spec.base = 16;
+
+ switch (fmt[1]) {
+ case 'd':
+ num = *(const dma_addr_t *)addr;
+ spec.field_width = sizeof(dma_addr_t) * 2 + 2;
+ break;
+ case 'p':
+ default:
+ num = *(const phys_addr_t *)addr;
+ spec.field_width = sizeof(phys_addr_t) * 2 + 2;
+ break;
+ }
+
+ return number(buf, end, num, spec);
+}
+
int kptr_restrict __read_mostly;
/*
@@ -1141,7 +1246,10 @@ int kptr_restrict __read_mostly;
* N no separator
* The maximum supported length is 64 bytes of the input. Consider
* to use print_hex_dump() for the larger input.
- * - 'a' For a phys_addr_t type and its derivative types (passed by reference)
+ * - 'a[pd]' For address types [p] phys_addr_t, [d] dma_addr_t and derivatives
+ * (default assumed to be phys_addr_t, passed by reference)
+ * - 'd[234]' For a dentry name (optionally 2-4 last components)
+ * - 'D[234]' Same as 'd' but for a struct file
*
* Note: The difference between 'S' and 'F' is that on ia64 and ppc64
* function pointers are really function descriptors, which contain a
@@ -1236,11 +1344,37 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
spec.field_width = default_width;
return string(buf, end, "pK-error", spec);
}
- if (!((kptr_restrict == 0) ||
- (kptr_restrict == 1 &&
- has_capability_noaudit(current, CAP_SYSLOG))))
+
+ switch (kptr_restrict) {
+ case 0:
+ /* Always print %pK values */
+ break;
+ case 1: {
+ /*
+ * Only print the real pointer value if the current
+ * process has CAP_SYSLOG and is running with the
+ * same credentials it started with. This is because
+ * access to files is checked at open() time, but %pK
+ * checks permission at read() time. We don't want to
+ * leak pointer values if a binary opens a file using
+ * %pK and then elevates privileges before reading it.
+ */
+ const struct cred *cred = current_cred();
+
+ if (!has_capability_noaudit(current, CAP_SYSLOG) ||
+ !uid_eq(cred->euid, cred->uid) ||
+ !gid_eq(cred->egid, cred->gid))
+ ptr = NULL;
+ break;
+ }
+ case 2:
+ default:
+ /* Always print 0's for %pK */
ptr = NULL;
+ break;
+ }
break;
+
case 'N':
switch (fmt[1]) {
case 'F':
@@ -1248,11 +1382,13 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
}
break;
case 'a':
- spec.flags |= SPECIAL | SMALL | ZEROPAD;
- spec.field_width = sizeof(phys_addr_t) * 2 + 2;
- spec.base = 16;
- return number(buf, end,
- (unsigned long long) *((phys_addr_t *)ptr), spec);
+ return address_val(buf, end, ptr, spec, fmt);
+ case 'd':
+ return dentry_name(buf, end, ptr, spec, fmt);
+ case 'D':
+ return dentry_name(buf, end,
+ ((const struct file *)ptr)->f_path.dentry,
+ spec, fmt);
}
spec.flags |= SMALL;
if (spec.field_width == -1) {
@@ -1401,10 +1537,6 @@ qualifier:
return fmt - start;
/* skip alnum */
- case 'n':
- spec->type = FORMAT_TYPE_NRCHARS;
- return ++fmt - start;
-
case '%':
spec->type = FORMAT_TYPE_PERCENT_CHAR;
return ++fmt - start;
@@ -1427,6 +1559,15 @@ qualifier:
case 'u':
break;
+ case 'n':
+ /*
+ * Since %n poses a greater security risk than utility, treat
+ * it as an invalid format specifier. Warn about its use so
+ * that new instances don't get added.
+ */
+ WARN_ONCE(1, "Please remove ignored %%n in '%s'\n", fmt);
+ /* Fall-through */
+
default:
spec->type = FORMAT_TYPE_INVALID;
return fmt - start;
@@ -1600,22 +1741,6 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
++str;
break;
- case FORMAT_TYPE_NRCHARS: {
- u8 qualifier = spec.qualifier;
-
- if (qualifier == 'l') {
- long *ip = va_arg(args, long *);
- *ip = (str - buf);
- } else if (_tolower(qualifier) == 'z') {
- size_t *ip = va_arg(args, size_t *);
- *ip = (str - buf);
- } else {
- int *ip = va_arg(args, int *);
- *ip = (str - buf);
- }
- break;
- }
-
default:
switch (spec.type) {
case FORMAT_TYPE_LONG_LONG:
@@ -1890,19 +2015,6 @@ do { \
fmt++;
break;
- case FORMAT_TYPE_NRCHARS: {
- /* skip %n 's argument */
- u8 qualifier = spec.qualifier;
- void *skip_arg;
- if (qualifier == 'l')
- skip_arg = va_arg(args, long *);
- else if (_tolower(qualifier) == 'z')
- skip_arg = va_arg(args, size_t *);
- else
- skip_arg = va_arg(args, int *);
- break;
- }
-
default:
switch (spec.type) {
@@ -2061,10 +2173,6 @@ int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
++str;
break;
- case FORMAT_TYPE_NRCHARS:
- /* skip */
- break;
-
default: {
unsigned long long num;
@@ -2239,7 +2347,7 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
break;
base = 10;
- is_sign = 0;
+ is_sign = false;
switch (*fmt++) {
case 'c':
@@ -2278,7 +2386,7 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
case 'i':
base = 0;
case 'd':
- is_sign = 1;
+ is_sign = true;
case 'u':
break;
case '%':
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-10 05:53:12 +0000