mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-23 22:30:51 +07:00
9e914f59cc
[ Upstream commit 900fdc4573766dd43b847b4f54bd4a1ee2bc7360 ]
The existing code attempted to handle numbers by doing a strto[u]l(),
ignoring the field width, and then repeatedly dividing to extract the
field out of the full converted value. If the string contains a run of
valid digits longer than will fit in a long or long long, this would
overflow and no amount of dividing can recover the correct value.
This patch fixes vsscanf() to obey number field widths when parsing
the number.
A new _parse_integer_limit() is added that takes a limit for the number
of characters to parse. The number field conversion in vsscanf is changed
to use this new function.
If a number starts with a radix prefix, the field width must be long
enough for at last one digit after the prefix. If not, it will be handled
like this:
sscanf("0x4", "%1i", &i): i=0, scanning continues with the 'x'
sscanf("0x4", "%2i", &i): i=0, scanning continues with the '4'
This is consistent with the observed behaviour of userland sscanf.
Note that this patch does NOT fix the problem of a single field value
overflowing the target type. So for example:
sscanf("123456789abcdef", "%x", &i);
Will not produce the correct result because the value obviously overflows
INT_MAX. But sscanf will report a successful conversion.
Note that where a very large number is used to mean "unlimited", the value
INT_MAX is used for consistency with the behaviour of vsnprintf().
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210514161206.30821-2-rf@opensource.cirrus.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
12 lines
411 B
C
12 lines
411 B
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _LIB_KSTRTOX_H
|
|
#define _LIB_KSTRTOX_H
|
|
|
|
#define KSTRTOX_OVERFLOW (1U << 31)
|
|
const char *_parse_integer_fixup_radix(const char *s, unsigned int *base);
|
|
unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned long long *res,
|
|
size_t max_chars);
|
|
unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *res);
|
|
|
|
#endif
|