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__vfscanf_internal: fix aliasing violation (bug 26690)

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As noted in <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97264>, the cast
in the call to the read_int function is an aliasing violation.  Change the
type of local variable f to a pointer to unsigned, which allows to
eliminate most casts while only adding three new ones.
This commit is contained in:
Andreas Schwab
2020-10-01 13:59:13 +02:00
parent 8f8052c2aa
commit c0e9ddf59e
1 changed files with 11 additions and 11 deletions
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22
stdio-common/vfscanf-internal.c
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@ -277,7 +277,7 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr,
#endif #endif
{ {
va_list arg; va_list arg;
const CHAR_T *f = format; const UCHAR_T *f = (const UCHAR_T *) format;
UCHAR_T fc; /* Current character of the format. */ UCHAR_T fc; /* Current character of the format. */
WINT_T done = 0; /* Assignments done. */ WINT_T done = 0; /* Assignments done. */
size_t read_in = 0; /* Chars read in. */ size_t read_in = 0; /* Chars read in. */
@ -415,10 +415,11 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr,
#endif #endif
#ifndef COMPILE_WSCANF #ifndef COMPILE_WSCANF
if (!isascii ((unsigned char) *f)) if (!isascii (*f))
{ {
/* Non-ASCII, may be a multibyte. */ /* Non-ASCII, may be a multibyte. */
int len = __mbrlen (f, strlen (f), &state); int len = __mbrlen ((const char *) f, strlen ((const char *) f),
&state);
if (len > 0) if (len > 0)
{ {
do do
@ -426,7 +427,7 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr,
c = inchar (); c = inchar ();
if (__glibc_unlikely (c == EOF)) if (__glibc_unlikely (c == EOF))
input_error (); input_error ();
else if (c != (unsigned char) *f++) else if (c != *f++)
{ {
ungetc_not_eof (c, s); ungetc_not_eof (c, s);
conv_error (); conv_error ();
@ -484,9 +485,9 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr,
char_buffer_rewind (&charbuf); char_buffer_rewind (&charbuf);
/* Check for a positional parameter specification. */ /* Check for a positional parameter specification. */
if (ISDIGIT ((UCHAR_T) *f)) if (ISDIGIT (*f))
{ {
argpos = read_int ((const UCHAR_T **) &f); argpos = read_int (&f);
if (*f == L_('$')) if (*f == L_('$'))
++f; ++f;
else else
@ -521,8 +522,8 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr,
/* Find the maximum field width. */ /* Find the maximum field width. */
width = 0; width = 0;
if (ISDIGIT ((UCHAR_T) *f)) if (ISDIGIT (*f))
width = read_int ((const UCHAR_T **) &f); width = read_int (&f);
got_width: got_width:
if (width == 0) if (width == 0)
width = -1; width = -1;
@ -2522,12 +2523,11 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr,
} }
while ((fc = *f++) != '\0' && fc != ']') while ((fc = *f++) != '\0' && fc != ']')
if (fc == '-' && *f != '\0' && *f != ']' if (fc == '-' && *f != '\0' && *f != ']' && f[-2] <= *f)
&& (unsigned char) f[-2] <= (unsigned char) *f)
{ {
/* Add all characters from the one before the '-' /* Add all characters from the one before the '-'
up to (but not including) the next format char. */ up to (but not including) the next format char. */
for (fc = (unsigned char) f[-2]; fc < (unsigned char) *f; ++fc) for (fc = f[-2]; fc < *f; ++fc)
((char *)charbuf.scratch.data)[fc] = 1; ((char *)charbuf.scratch.data)[fc] = 1;
} }
else else