* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
+#include <linux/uaccess.h>
+
#include "lttng-filter.h"
+/*
+ * get_char should be called with page fault handler disabled if it is expected
+ * to handle user-space read.
+ */
+static
+char get_char(struct estack_entry *reg, size_t offset)
+{
+ if (unlikely(offset >= reg->u.s.seq_len))
+ return '\0';
+ if (reg->u.s.user) {
+ char c;
+
+ /* Handle invalid access as end of string. */
+ if (unlikely(!access_ok(VERIFY_READ,
+ reg->u.s.user_str + offset,
+ sizeof(c))))
+ return '\0';
+ /* Handle fault (nonzero return value) as end of string. */
+ if (unlikely(__copy_from_user_inatomic(&c,
+ reg->u.s.user_str + offset,
+ sizeof(c))))
+ return '\0';
+ return c;
+ } else {
+ return reg->u.s.str[offset];
+ }
+}
+
/*
* -1: wildcard found.
* -2: unknown escape char.
* 0: normal char.
*/
-
static
-int parse_char(const char **p)
+int parse_char(struct estack_entry *reg, char *c, size_t *offset)
{
- switch (**p) {
+ switch (*c) {
case '\\':
- (*p)++;
- switch (**p) {
+ (*offset)++;
+ *c = get_char(reg, *offset);
+ switch (*c) {
case '\\':
case '*':
return 0;
static
int stack_strcmp(struct estack *stack, int top, const char *cmp_type)
{
- const char *p = estack_bx(stack, top)->u.s.str, *q = estack_ax(stack, top)->u.s.str;
- int ret;
- int diff;
+ size_t offset_bx = 0, offset_ax = 0;
+ int diff, has_user = 0;
+ mm_segment_t old_fs;
+
+ if (estack_bx(stack, top)->u.s.user
+ || estack_ax(stack, top)->u.s.user) {
+ has_user = 1;
+ old_fs = get_fs();
+ set_fs(KERNEL_DS);
+ pagefault_disable();
+ }
for (;;) {
+ int ret;
int escaped_r0 = 0;
+ char char_bx, char_ax;
- if (unlikely(p - estack_bx(stack, top)->u.s.str > estack_bx(stack, top)->u.s.seq_len || *p == '\0')) {
- if (q - estack_ax(stack, top)->u.s.str > estack_ax(stack, top)->u.s.seq_len || *q == '\0') {
- return 0;
+ char_bx = get_char(estack_bx(stack, top), offset_bx);
+ char_ax = get_char(estack_ax(stack, top), offset_ax);
+
+ if (unlikely(char_bx == '\0')) {
+ if (char_ax == '\0') {
+ diff = 0;
+ break;
} else {
if (estack_ax(stack, top)->u.s.literal) {
- ret = parse_char(&q);
- if (ret == -1)
- return 0;
+ ret = parse_char(estack_ax(stack, top),
+ &char_ax, &offset_ax);
+ if (ret == -1) {
+ diff = 0;
+ break;
+ }
}
- return -1;
+ diff = -1;
+ break;
}
}
- if (unlikely(q - estack_ax(stack, top)->u.s.str > estack_ax(stack, top)->u.s.seq_len || *q == '\0')) {
- if (p - estack_bx(stack, top)->u.s.str > estack_bx(stack, top)->u.s.seq_len || *p == '\0') {
- return 0;
+ if (unlikely(char_ax == '\0')) {
+ if (char_bx == '\0') {
+ diff = 0;
+ break;
} else {
if (estack_bx(stack, top)->u.s.literal) {
- ret = parse_char(&p);
- if (ret == -1)
- return 0;
+ ret = parse_char(estack_bx(stack, top),
+ &char_bx, &offset_bx);
+ if (ret == -1) {
+ diff = 0;
+ break;
+ }
}
- return 1;
+ diff = 1;
+ break;
}
}
if (estack_bx(stack, top)->u.s.literal) {
- ret = parse_char(&p);
+ ret = parse_char(estack_bx(stack, top),
+ &char_bx, &offset_bx);
if (ret == -1) {
- return 0;
+ diff = 0;
+ break;
} else if (ret == -2) {
escaped_r0 = 1;
}
/* else compare both char */
}
if (estack_ax(stack, top)->u.s.literal) {
- ret = parse_char(&q);
+ ret = parse_char(estack_ax(stack, top),
+ &char_ax, &offset_ax);
if (ret == -1) {
- return 0;
+ diff = 0;
+ break;
} else if (ret == -2) {
- if (!escaped_r0)
- return -1;
+ if (!escaped_r0) {
+ diff = -1;
+ break;
+ }
} else {
- if (escaped_r0)
- return 1;
+ if (escaped_r0) {
+ diff = 1;
+ break;
+ }
}
} else {
- if (escaped_r0)
- return 1;
+ if (escaped_r0) {
+ diff = 1;
+ break;
+ }
}
- diff = *p - *q;
+ diff = char_bx - char_ax;
if (diff != 0)
break;
- p++;
- q++;
+ offset_bx++;
+ offset_ax++;
+ }
+ if (has_user) {
+ pagefault_enable();
+ set_fs(old_fs);
}
return diff;
}
[ FILTER_OP_GET_CONTEXT_REF_STRING ] = &&LABEL_FILTER_OP_GET_CONTEXT_REF_STRING,
[ FILTER_OP_GET_CONTEXT_REF_S64 ] = &&LABEL_FILTER_OP_GET_CONTEXT_REF_S64,
[ FILTER_OP_GET_CONTEXT_REF_DOUBLE ] = &&LABEL_FILTER_OP_GET_CONTEXT_REF_DOUBLE,
+
+ /* load userspace field ref */
+ [ FILTER_OP_LOAD_FIELD_REF_USER_STRING ] = &&LABEL_FILTER_OP_LOAD_FIELD_REF_USER_STRING,
+ [ FILTER_OP_LOAD_FIELD_REF_USER_SEQUENCE ] = &&LABEL_FILTER_OP_LOAD_FIELD_REF_USER_SEQUENCE,
};
#endif /* #ifndef INTERPRETER_USE_SWITCH */
}
estack_ax(stack, top)->u.s.seq_len = UINT_MAX;
estack_ax(stack, top)->u.s.literal = 0;
+ estack_ax(stack, top)->u.s.user = 0;
dbg_printk("ref load string %s\n", estack_ax(stack, top)->u.s.str);
next_pc += sizeof(struct load_op) + sizeof(struct field_ref);
PO;
goto end;
}
estack_ax(stack, top)->u.s.literal = 0;
+ estack_ax(stack, top)->u.s.user = 0;
next_pc += sizeof(struct load_op) + sizeof(struct field_ref);
PO;
}
estack_ax(stack, top)->u.s.str = insn->data;
estack_ax(stack, top)->u.s.seq_len = UINT_MAX;
estack_ax(stack, top)->u.s.literal = 1;
+ estack_ax(stack, top)->u.s.user = 0;
next_pc += sizeof(struct load_op) + strlen(insn->data) + 1;
PO;
}
}
estack_ax(stack, top)->u.s.seq_len = UINT_MAX;
estack_ax(stack, top)->u.s.literal = 0;
+ estack_ax(stack, top)->u.s.user = 0;
dbg_printk("ref get context string %s\n", estack_ax(stack, top)->u.s.str);
next_pc += sizeof(struct load_op) + sizeof(struct field_ref);
PO;
PO;
}
+ /* load userspace field ref */
+ OP(FILTER_OP_LOAD_FIELD_REF_USER_STRING):
+ {
+ struct load_op *insn = (struct load_op *) pc;
+ struct field_ref *ref = (struct field_ref *) insn->data;
+
+ dbg_printk("load field ref offset %u type user string\n",
+ ref->offset);
+ estack_push(stack, top, ax, bx);
+ estack_ax(stack, top)->u.s.str =
+ *(const char * const *) &filter_stack_data[ref->offset];
+ if (unlikely(!estack_ax(stack, top)->u.s.str)) {
+ dbg_printk("Filter warning: loading a NULL string.\n");
+ ret = -EINVAL;
+ goto end;
+ }
+ estack_ax(stack, top)->u.s.seq_len = UINT_MAX;
+ estack_ax(stack, top)->u.s.literal = 0;
+ estack_ax(stack, top)->u.s.user = 1;
+ dbg_printk("ref load string %s\n", estack_ax(stack, top)->u.s.str);
+ next_pc += sizeof(struct load_op) + sizeof(struct field_ref);
+ PO;
+ }
+
+ OP(FILTER_OP_LOAD_FIELD_REF_USER_SEQUENCE):
+ {
+ struct load_op *insn = (struct load_op *) pc;
+ struct field_ref *ref = (struct field_ref *) insn->data;
+
+ dbg_printk("load field ref offset %u type user sequence\n",
+ ref->offset);
+ estack_push(stack, top, ax, bx);
+ estack_ax(stack, top)->u.s.seq_len =
+ *(unsigned long *) &filter_stack_data[ref->offset];
+ estack_ax(stack, top)->u.s.str =
+ *(const char **) (&filter_stack_data[ref->offset
+ + sizeof(unsigned long)]);
+ if (unlikely(!estack_ax(stack, top)->u.s.str)) {
+ dbg_printk("Filter warning: loading a NULL sequence.\n");
+ ret = -EINVAL;
+ goto end;
+ }
+ estack_ax(stack, top)->u.s.literal = 0;
+ estack_ax(stack, top)->u.s.user = 1;
+ next_pc += sizeof(struct load_op) + sizeof(struct field_ref);
+ PO;
+ }
+
END_OP
end:
/* return 0 (discard) on error */
projects / lttng-modules.git / blobdiff