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taskset: fix cpuset list parser 

taskset hangs when executed with badly formatted cpuset list, for
example:

	 $ taskset -c 0--1 true

The current cpuset list parser is pretty weak as based on scanf()
without strings verification ("-1" as input for "%u" returns
unexpected number). It seems faster and better to use strtoul() and
isdigit().

Addresses: https://github.com/karelzak/util-linux/issues/77
Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak 2019-03-20 13:12:25 +01:00
parent 06c141a99a
commit 65bcbf105b
1 changed files with 24 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
lib/cpuset.c
View File

@ -260,6 +260,19 @@ int cpumask_parse(const char *str, cpu_set_t *set, size_t setsize)
return 0;
}
static int nextnumber(const char *str, char **end, unsigned int *result)
{
errno = 0;
if (str == NULL || *str == '\0' || !isdigit(*str))
return -EINVAL;
*result = (unsigned int) strtoul(str, end, 10);
if (errno)
return -errno;
if (str == *end)
return -EINVAL;
return 0;
}
/*
* Parses string with list of CPU ranges.
* Returns 0 on success.
@ -272,7 +285,7 @@ int cpulist_parse(const char *str, cpu_set_t *set, size_t setsize, int fail)
{
size_t max = cpuset_nbits(setsize);
const char *p, *q;
int r = 0;
char *end = NULL;
q = str;
CPU_ZERO_S(setsize, set);
@ -282,21 +295,24 @@ int cpulist_parse(const char *str, cpu_set_t *set, size_t setsize, int fail)
unsigned int b; /* end of range */
unsigned int s; /* stride */
const char *c1, *c2;
char c;
if ((r = sscanf(p, "%u%c", &a, &c)) < 1)
if (nextnumber(p, &end, &a) != 0)
return 1;
b = a;
s = 1;
p = end;
c1 = nexttoken(p, '-');
c2 = nexttoken(p, ',');
if (c1 != NULL && (c2 == NULL || c1 < c2)) {
if ((r = sscanf(c1, "%u%c", &b, &c)) < 1)
if (nextnumber(c1, &end, &b) != 0)
return 1;
c1 = nexttoken(c1, ':');
c1 = end && *end ? nexttoken(end, ':') : NULL;
if (c1 != NULL && (c2 == NULL || c1 < c2)) {
if ((r = sscanf(c1, "%u%c", &s, &c)) < 1)
if (nextnumber(c1, &end, &s) != 0)
return 1;
if (s == 0)
return 1;
@ -313,7 +329,7 @@ int cpulist_parse(const char *str, cpu_set_t *set, size_t setsize, int fail)
}
}
if (r == 2)
if (end && *end)
return 1;
return 0;
}
@ -390,7 +406,7 @@ int main(int argc, char *argv[])
usage_err:
fprintf(stderr,
"usage: %s [--ncpus <num>] --mask <mask> | --range <list>",
"usage: %s [--ncpus <num>] --mask <mask> | --range <list>\n",
program_invocation_short_name);
exit(EXIT_FAILURE);
}