* [2.32 COMMITTED] __vfscanf_internal: fix aliasing violation (bug 26690)
@ 2021-01-21 13:52 Szabolcs Nagy
0 siblings, 0 replies; only message in thread
From: Szabolcs Nagy @ 2021-01-21 13:52 UTC (permalink / raw)
To: libc-stable; +Cc: Andreas Schwab
From: Andreas Schwab <schwab@suse.de>
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.
(cherry picked from commit c0e9ddf59e73e21afe15fca4e94cf7b4b7359bf2)
---
stdio-common/vfscanf-internal.c | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)
diff --git a/stdio-common/vfscanf-internal.c b/stdio-common/vfscanf-internal.c
index 95b46dcbeb..3a323547f9 100644
--- a/stdio-common/vfscanf-internal.c
+++ b/stdio-common/vfscanf-internal.c
@@ -277,7 +277,7 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr,
#endif
{
va_list arg;
- const CHAR_T *f = format;
+ const UCHAR_T *f = (const UCHAR_T *) format;
UCHAR_T fc; /* Current character of the format. */
WINT_T done = 0; /* Assignments done. */
size_t read_in = 0; /* Chars read in. */
@@ -415,10 +415,11 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr,
#endif
#ifndef COMPILE_WSCANF
- if (!isascii ((unsigned char) *f))
+ if (!isascii (*f))
{
/* 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)
{
do
@@ -426,7 +427,7 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr,
c = inchar ();
if (__glibc_unlikely (c == EOF))
input_error ();
- else if (c != (unsigned char) *f++)
+ else if (c != *f++)
{
ungetc_not_eof (c, s);
conv_error ();
@@ -484,9 +485,9 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr,
char_buffer_rewind (&charbuf);
/* 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_('$'))
++f;
else
@@ -521,8 +522,8 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr,
/* Find the maximum field width. */
width = 0;
- if (ISDIGIT ((UCHAR_T) *f))
- width = read_int ((const UCHAR_T **) &f);
+ if (ISDIGIT (*f))
+ width = read_int (&f);
got_width:
if (width == 0)
width = -1;
@@ -2522,12 +2523,11 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr,
}
while ((fc = *f++) != '\0' && fc != ']')
- if (fc == '-' && *f != '\0' && *f != ']'
- && (unsigned char) f[-2] <= (unsigned char) *f)
+ if (fc == '-' && *f != '\0' && *f != ']' && f[-2] <= *f)
{
/* Add all characters from the one before the '-'
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;
}
else
--
2.17.1
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