builtins, and also the various sanitizers. Support for these will be added in a later commit.
560 lines
17 KiB
C++
560 lines
17 KiB
C++
//===-- sanitizer_common_interceptors_format.inc ----------------*- C++ -*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// Scanf/printf implementation for use in *Sanitizer interceptors.
|
|
// Follows http://pubs.opengroup.org/onlinepubs/9699919799/functions/fscanf.html
|
|
// and http://pubs.opengroup.org/onlinepubs/9699919799/functions/fprintf.html
|
|
// with a few common GNU extensions.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
#include <stdarg.h>
|
|
|
|
static const char *parse_number(const char *p, int *out) {
|
|
*out = internal_atoll(p);
|
|
while (*p >= '0' && *p <= '9')
|
|
++p;
|
|
return p;
|
|
}
|
|
|
|
static const char *maybe_parse_param_index(const char *p, int *out) {
|
|
// n$
|
|
if (*p >= '0' && *p <= '9') {
|
|
int number;
|
|
const char *q = parse_number(p, &number);
|
|
CHECK(q);
|
|
if (*q == '$') {
|
|
*out = number;
|
|
p = q + 1;
|
|
}
|
|
}
|
|
|
|
// Otherwise, do not change p. This will be re-parsed later as the field
|
|
// width.
|
|
return p;
|
|
}
|
|
|
|
static bool char_is_one_of(char c, const char *s) {
|
|
return !!internal_strchr(s, c);
|
|
}
|
|
|
|
static const char *maybe_parse_length_modifier(const char *p, char ll[2]) {
|
|
if (char_is_one_of(*p, "jztLq")) {
|
|
ll[0] = *p;
|
|
++p;
|
|
} else if (*p == 'h') {
|
|
ll[0] = 'h';
|
|
++p;
|
|
if (*p == 'h') {
|
|
ll[1] = 'h';
|
|
++p;
|
|
}
|
|
} else if (*p == 'l') {
|
|
ll[0] = 'l';
|
|
++p;
|
|
if (*p == 'l') {
|
|
ll[1] = 'l';
|
|
++p;
|
|
}
|
|
}
|
|
return p;
|
|
}
|
|
|
|
// Returns true if the character is an integer conversion specifier.
|
|
static bool format_is_integer_conv(char c) {
|
|
return char_is_one_of(c, "diouxXn");
|
|
}
|
|
|
|
// Returns true if the character is an floating point conversion specifier.
|
|
static bool format_is_float_conv(char c) {
|
|
return char_is_one_of(c, "aAeEfFgG");
|
|
}
|
|
|
|
// Returns string output character size for string-like conversions,
|
|
// or 0 if the conversion is invalid.
|
|
static int format_get_char_size(char convSpecifier,
|
|
const char lengthModifier[2]) {
|
|
if (char_is_one_of(convSpecifier, "CS")) {
|
|
return sizeof(wchar_t);
|
|
}
|
|
|
|
if (char_is_one_of(convSpecifier, "cs[")) {
|
|
if (lengthModifier[0] == 'l' && lengthModifier[1] == '\0')
|
|
return sizeof(wchar_t);
|
|
else if (lengthModifier[0] == '\0')
|
|
return sizeof(char);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
enum FormatStoreSize {
|
|
// Store size not known in advance; can be calculated as wcslen() of the
|
|
// destination buffer.
|
|
FSS_WCSLEN = -2,
|
|
// Store size not known in advance; can be calculated as strlen() of the
|
|
// destination buffer.
|
|
FSS_STRLEN = -1,
|
|
// Invalid conversion specifier.
|
|
FSS_INVALID = 0
|
|
};
|
|
|
|
// Returns the memory size of a format directive (if >0), or a value of
|
|
// FormatStoreSize.
|
|
static int format_get_value_size(char convSpecifier,
|
|
const char lengthModifier[2],
|
|
bool promote_float) {
|
|
if (format_is_integer_conv(convSpecifier)) {
|
|
switch (lengthModifier[0]) {
|
|
case 'h':
|
|
return lengthModifier[1] == 'h' ? sizeof(char) : sizeof(short);
|
|
case 'l':
|
|
return lengthModifier[1] == 'l' ? sizeof(long long) : sizeof(long);
|
|
case 'q':
|
|
return sizeof(long long);
|
|
case 'L':
|
|
return sizeof(long long);
|
|
case 'j':
|
|
return sizeof(INTMAX_T);
|
|
case 'z':
|
|
return sizeof(SIZE_T);
|
|
case 't':
|
|
return sizeof(PTRDIFF_T);
|
|
case 0:
|
|
return sizeof(int);
|
|
default:
|
|
return FSS_INVALID;
|
|
}
|
|
}
|
|
|
|
if (format_is_float_conv(convSpecifier)) {
|
|
switch (lengthModifier[0]) {
|
|
case 'L':
|
|
case 'q':
|
|
return sizeof(long double);
|
|
case 'l':
|
|
return lengthModifier[1] == 'l' ? sizeof(long double)
|
|
: sizeof(double);
|
|
case 0:
|
|
// Printf promotes floats to doubles but scanf does not
|
|
return promote_float ? sizeof(double) : sizeof(float);
|
|
default:
|
|
return FSS_INVALID;
|
|
}
|
|
}
|
|
|
|
if (convSpecifier == 'p') {
|
|
if (lengthModifier[0] != 0)
|
|
return FSS_INVALID;
|
|
return sizeof(void *);
|
|
}
|
|
|
|
return FSS_INVALID;
|
|
}
|
|
|
|
struct ScanfDirective {
|
|
int argIdx; // argument index, or -1 if not specified ("%n$")
|
|
int fieldWidth;
|
|
const char *begin;
|
|
const char *end;
|
|
bool suppressed; // suppress assignment ("*")
|
|
bool allocate; // allocate space ("m")
|
|
char lengthModifier[2];
|
|
char convSpecifier;
|
|
bool maybeGnuMalloc;
|
|
};
|
|
|
|
// Parse scanf format string. If a valid directive in encountered, it is
|
|
// returned in dir. This function returns the pointer to the first
|
|
// unprocessed character, or 0 in case of error.
|
|
// In case of the end-of-string, a pointer to the closing \0 is returned.
|
|
static const char *scanf_parse_next(const char *p, bool allowGnuMalloc,
|
|
ScanfDirective *dir) {
|
|
internal_memset(dir, 0, sizeof(*dir));
|
|
dir->argIdx = -1;
|
|
|
|
while (*p) {
|
|
if (*p != '%') {
|
|
++p;
|
|
continue;
|
|
}
|
|
dir->begin = p;
|
|
++p;
|
|
// %%
|
|
if (*p == '%') {
|
|
++p;
|
|
continue;
|
|
}
|
|
if (*p == '\0') {
|
|
return 0;
|
|
}
|
|
// %n$
|
|
p = maybe_parse_param_index(p, &dir->argIdx);
|
|
CHECK(p);
|
|
// *
|
|
if (*p == '*') {
|
|
dir->suppressed = true;
|
|
++p;
|
|
}
|
|
// Field width
|
|
if (*p >= '0' && *p <= '9') {
|
|
p = parse_number(p, &dir->fieldWidth);
|
|
CHECK(p);
|
|
if (dir->fieldWidth <= 0) // Width if at all must be non-zero
|
|
return 0;
|
|
}
|
|
// m
|
|
if (*p == 'm') {
|
|
dir->allocate = true;
|
|
++p;
|
|
}
|
|
// Length modifier.
|
|
p = maybe_parse_length_modifier(p, dir->lengthModifier);
|
|
// Conversion specifier.
|
|
dir->convSpecifier = *p++;
|
|
// Consume %[...] expression.
|
|
if (dir->convSpecifier == '[') {
|
|
if (*p == '^')
|
|
++p;
|
|
if (*p == ']')
|
|
++p;
|
|
while (*p && *p != ']')
|
|
++p;
|
|
if (*p == 0)
|
|
return 0; // unexpected end of string
|
|
// Consume the closing ']'.
|
|
++p;
|
|
}
|
|
// This is unfortunately ambiguous between old GNU extension
|
|
// of %as, %aS and %a[...] and newer POSIX %a followed by
|
|
// letters s, S or [.
|
|
if (allowGnuMalloc && dir->convSpecifier == 'a' &&
|
|
!dir->lengthModifier[0]) {
|
|
if (*p == 's' || *p == 'S') {
|
|
dir->maybeGnuMalloc = true;
|
|
++p;
|
|
} else if (*p == '[') {
|
|
// Watch for %a[h-j%d], if % appears in the
|
|
// [...] range, then we need to give up, we don't know
|
|
// if scanf will parse it as POSIX %a [h-j %d ] or
|
|
// GNU allocation of string with range dh-j plus %.
|
|
const char *q = p + 1;
|
|
if (*q == '^')
|
|
++q;
|
|
if (*q == ']')
|
|
++q;
|
|
while (*q && *q != ']' && *q != '%')
|
|
++q;
|
|
if (*q == 0 || *q == '%')
|
|
return 0;
|
|
p = q + 1; // Consume the closing ']'.
|
|
dir->maybeGnuMalloc = true;
|
|
}
|
|
}
|
|
dir->end = p;
|
|
break;
|
|
}
|
|
return p;
|
|
}
|
|
|
|
static int scanf_get_value_size(ScanfDirective *dir) {
|
|
if (dir->allocate) {
|
|
if (!char_is_one_of(dir->convSpecifier, "cCsS["))
|
|
return FSS_INVALID;
|
|
return sizeof(char *);
|
|
}
|
|
|
|
if (dir->maybeGnuMalloc) {
|
|
if (dir->convSpecifier != 'a' || dir->lengthModifier[0])
|
|
return FSS_INVALID;
|
|
// This is ambiguous, so check the smaller size of char * (if it is
|
|
// a GNU extension of %as, %aS or %a[...]) and float (if it is
|
|
// POSIX %a followed by s, S or [ letters).
|
|
return sizeof(char *) < sizeof(float) ? sizeof(char *) : sizeof(float);
|
|
}
|
|
|
|
if (char_is_one_of(dir->convSpecifier, "cCsS[")) {
|
|
bool needsTerminator = char_is_one_of(dir->convSpecifier, "sS[");
|
|
unsigned charSize =
|
|
format_get_char_size(dir->convSpecifier, dir->lengthModifier);
|
|
if (charSize == 0)
|
|
return FSS_INVALID;
|
|
if (dir->fieldWidth == 0) {
|
|
if (!needsTerminator)
|
|
return charSize;
|
|
return (charSize == sizeof(char)) ? FSS_STRLEN : FSS_WCSLEN;
|
|
}
|
|
return (dir->fieldWidth + needsTerminator) * charSize;
|
|
}
|
|
|
|
return format_get_value_size(dir->convSpecifier, dir->lengthModifier, false);
|
|
}
|
|
|
|
// Common part of *scanf interceptors.
|
|
// Process format string and va_list, and report all store ranges.
|
|
// Stops when "consuming" n_inputs input items.
|
|
static void scanf_common(void *ctx, int n_inputs, bool allowGnuMalloc,
|
|
const char *format, va_list aq) {
|
|
CHECK_GT(n_inputs, 0);
|
|
const char *p = format;
|
|
|
|
COMMON_INTERCEPTOR_READ_RANGE(ctx, format, internal_strlen(format) + 1);
|
|
|
|
while (*p) {
|
|
ScanfDirective dir;
|
|
p = scanf_parse_next(p, allowGnuMalloc, &dir);
|
|
if (!p)
|
|
break;
|
|
if (dir.convSpecifier == 0) {
|
|
// This can only happen at the end of the format string.
|
|
CHECK_EQ(*p, 0);
|
|
break;
|
|
}
|
|
// Here the directive is valid. Do what it says.
|
|
if (dir.argIdx != -1) {
|
|
// Unsupported.
|
|
break;
|
|
}
|
|
if (dir.suppressed)
|
|
continue;
|
|
int size = scanf_get_value_size(&dir);
|
|
if (size == FSS_INVALID) {
|
|
Report("WARNING: unexpected format specifier in scanf interceptor: "
|
|
"%.*s\n", dir.end - dir.begin, dir.begin);
|
|
break;
|
|
}
|
|
void *argp = va_arg(aq, void *);
|
|
if (dir.convSpecifier != 'n')
|
|
--n_inputs;
|
|
if (n_inputs < 0)
|
|
break;
|
|
if (size == FSS_STRLEN) {
|
|
size = internal_strlen((const char *)argp) + 1;
|
|
} else if (size == FSS_WCSLEN) {
|
|
// FIXME: actually use wcslen() to calculate it.
|
|
size = 0;
|
|
}
|
|
COMMON_INTERCEPTOR_WRITE_RANGE(ctx, argp, size);
|
|
}
|
|
}
|
|
|
|
#if SANITIZER_INTERCEPT_PRINTF
|
|
|
|
struct PrintfDirective {
|
|
int fieldWidth;
|
|
int fieldPrecision;
|
|
int argIdx; // width argument index, or -1 if not specified ("%*n$")
|
|
int precisionIdx; // precision argument index, or -1 if not specified (".*n$")
|
|
const char *begin;
|
|
const char *end;
|
|
bool starredWidth;
|
|
bool starredPrecision;
|
|
char lengthModifier[2];
|
|
char convSpecifier;
|
|
};
|
|
|
|
static const char *maybe_parse_number(const char *p, int *out) {
|
|
if (*p >= '0' && *p <= '9')
|
|
p = parse_number(p, out);
|
|
return p;
|
|
}
|
|
|
|
static const char *maybe_parse_number_or_star(const char *p, int *out,
|
|
bool *star) {
|
|
if (*p == '*') {
|
|
*star = true;
|
|
++p;
|
|
} else {
|
|
*star = false;
|
|
p = maybe_parse_number(p, out);
|
|
}
|
|
return p;
|
|
}
|
|
|
|
// Parse printf format string. Same as scanf_parse_next.
|
|
static const char *printf_parse_next(const char *p, PrintfDirective *dir) {
|
|
internal_memset(dir, 0, sizeof(*dir));
|
|
dir->argIdx = -1;
|
|
dir->precisionIdx = -1;
|
|
|
|
while (*p) {
|
|
if (*p != '%') {
|
|
++p;
|
|
continue;
|
|
}
|
|
dir->begin = p;
|
|
++p;
|
|
// %%
|
|
if (*p == '%') {
|
|
++p;
|
|
continue;
|
|
}
|
|
if (*p == '\0') {
|
|
return 0;
|
|
}
|
|
// %n$
|
|
p = maybe_parse_param_index(p, &dir->precisionIdx);
|
|
CHECK(p);
|
|
// Flags
|
|
while (char_is_one_of(*p, "'-+ #0")) {
|
|
++p;
|
|
}
|
|
// Field width
|
|
p = maybe_parse_number_or_star(p, &dir->fieldWidth,
|
|
&dir->starredWidth);
|
|
if (!p)
|
|
return 0;
|
|
// Precision
|
|
if (*p == '.') {
|
|
++p;
|
|
// Actual precision is optional (surprise!)
|
|
p = maybe_parse_number_or_star(p, &dir->fieldPrecision,
|
|
&dir->starredPrecision);
|
|
if (!p)
|
|
return 0;
|
|
// m$
|
|
if (dir->starredPrecision) {
|
|
p = maybe_parse_param_index(p, &dir->precisionIdx);
|
|
CHECK(p);
|
|
}
|
|
}
|
|
// Length modifier.
|
|
p = maybe_parse_length_modifier(p, dir->lengthModifier);
|
|
// Conversion specifier.
|
|
dir->convSpecifier = *p++;
|
|
dir->end = p;
|
|
break;
|
|
}
|
|
return p;
|
|
}
|
|
|
|
static int printf_get_value_size(PrintfDirective *dir) {
|
|
if (dir->convSpecifier == 'm') {
|
|
return sizeof(char *);
|
|
}
|
|
|
|
if (char_is_one_of(dir->convSpecifier, "cCsS")) {
|
|
unsigned charSize =
|
|
format_get_char_size(dir->convSpecifier, dir->lengthModifier);
|
|
if (charSize == 0)
|
|
return FSS_INVALID;
|
|
if (char_is_one_of(dir->convSpecifier, "sS")) {
|
|
return (charSize == sizeof(char)) ? FSS_STRLEN : FSS_WCSLEN;
|
|
}
|
|
return charSize;
|
|
}
|
|
|
|
return format_get_value_size(dir->convSpecifier, dir->lengthModifier, true);
|
|
}
|
|
|
|
#define SKIP_SCALAR_ARG(aq, convSpecifier, size) \
|
|
do { \
|
|
if (format_is_float_conv(convSpecifier)) { \
|
|
switch (size) { \
|
|
case 8: \
|
|
va_arg(*aq, double); \
|
|
break; \
|
|
case 12: \
|
|
va_arg(*aq, long double); \
|
|
break; \
|
|
case 16: \
|
|
va_arg(*aq, long double); \
|
|
break; \
|
|
default: \
|
|
Report("WARNING: unexpected floating-point arg size" \
|
|
" in printf interceptor: %d\n", size); \
|
|
return; \
|
|
} \
|
|
} else { \
|
|
switch (size) { \
|
|
case 1: \
|
|
case 2: \
|
|
case 4: \
|
|
va_arg(*aq, u32); \
|
|
break; \
|
|
case 8: \
|
|
va_arg(*aq, u64); \
|
|
break; \
|
|
default: \
|
|
Report("WARNING: unexpected arg size" \
|
|
" in printf interceptor: %d\n", size); \
|
|
return; \
|
|
} \
|
|
} \
|
|
} while (0)
|
|
|
|
// Common part of *printf interceptors.
|
|
// Process format string and va_list, and report all load ranges.
|
|
static void printf_common(void *ctx, const char *format, va_list aq) {
|
|
COMMON_INTERCEPTOR_READ_RANGE(ctx, format, internal_strlen(format) + 1);
|
|
|
|
const char *p = format;
|
|
|
|
while (*p) {
|
|
PrintfDirective dir;
|
|
p = printf_parse_next(p, &dir);
|
|
if (!p)
|
|
break;
|
|
if (dir.convSpecifier == 0) {
|
|
// This can only happen at the end of the format string.
|
|
CHECK_EQ(*p, 0);
|
|
break;
|
|
}
|
|
// Here the directive is valid. Do what it says.
|
|
if (dir.argIdx != -1 || dir.precisionIdx != -1) {
|
|
// Unsupported.
|
|
break;
|
|
}
|
|
if (dir.starredWidth) {
|
|
// Dynamic width
|
|
SKIP_SCALAR_ARG(&aq, 'd', sizeof(int));
|
|
}
|
|
if (dir.starredPrecision) {
|
|
// Dynamic precision
|
|
SKIP_SCALAR_ARG(&aq, 'd', sizeof(int));
|
|
}
|
|
int size = printf_get_value_size(&dir);
|
|
if (size == FSS_INVALID) {
|
|
Report("WARNING: unexpected format specifier in printf "
|
|
"interceptor: %.*s\n", dir.end - dir.begin, dir.begin);
|
|
break;
|
|
}
|
|
if (dir.convSpecifier == 'n') {
|
|
void *argp = va_arg(aq, void *);
|
|
COMMON_INTERCEPTOR_WRITE_RANGE(ctx, argp, size);
|
|
continue;
|
|
} else if (size == FSS_STRLEN) {
|
|
if (void *argp = va_arg(aq, void *)) {
|
|
if (dir.starredPrecision) {
|
|
// FIXME: properly support starred precision for strings.
|
|
size = 0;
|
|
} else if (dir.fieldPrecision > 0) {
|
|
// Won't read more than "precision" symbols.
|
|
size = internal_strnlen((const char *)argp, dir.fieldPrecision);
|
|
if (size < dir.fieldPrecision) size++;
|
|
} else {
|
|
// Whole string will be accessed.
|
|
size = internal_strlen((const char *)argp) + 1;
|
|
}
|
|
COMMON_INTERCEPTOR_READ_RANGE(ctx, argp, size);
|
|
}
|
|
} else if (size == FSS_WCSLEN) {
|
|
if (void *argp = va_arg(aq, void *)) {
|
|
// FIXME: Properly support wide-character strings (via wcsrtombs).
|
|
size = 0;
|
|
COMMON_INTERCEPTOR_READ_RANGE(ctx, argp, size);
|
|
}
|
|
} else {
|
|
// Skip non-pointer args
|
|
SKIP_SCALAR_ARG(&aq, dir.convSpecifier, size);
|
|
}
|
|
}
|
|
}
|
|
|
|
#endif // SANITIZER_INTERCEPT_PRINTF
|