seccomp: fix type mismatch when parsing syscall arguments filters

Specifier %lli was insufficient for the type uint64_t, all values
between 2^63-1 and 2^64-1 were silently converted to 2^63-1.

We can't use %llu since it doesn't handle hexadecimal. Instead, we
parse the values as strings and then use strtoull(3).

Signed-off-by: Felix Abecassis <fabecassis@nvidia.com>

src/lxc/seccomp.c

@@ -32,6 +32,7 @@
 #include "config.h"
 #include "log.h"
 #include "lxcseccomp.h"
+#include "utils.h"
 
 lxc_log_define(lxc_seccomp, lxc);
 
@@ -180,20 +181,32 @@ static int get_seccomp_arg_value(char *key, struct v2_rule_args *rule_args)
 	uint64_t mask = 0;
 	enum scmp_compare op = 0;
 	uint32_t index = 0;
-	char s[31] = {0};
+	char s[31] = {0}, v[24] = {0}, m[24] = {0};
 	char *tmp = NULL;
 
 	tmp = strchr(key, '[');
 	if (!tmp) {
 		ERROR("Failed to interpret args");
 		return -1;
 	}
-	ret = sscanf(tmp, "[%i,%lli,%30[^0-9^,],%lli", &index, (long long unsigned int *)&value, s, (long long unsigned int *)&mask);
+	ret = sscanf(tmp, "[%i,%23[^,],%30[^0-9^,],%23[^,]", &index, v, s, m);
 	if ((ret != 3 && ret != 4) || index >= 6) {
 		ERROR("Failed to interpret args value");
 		return -1;
 	}
 
+	ret = lxc_safe_uint64(v, &value);
+	if (ret < 0) {
+		ERROR("Invalid argument value");
+		return -1;
+	}
+
+	ret = lxc_safe_uint64(v, &mask);
+	if (ret < 0) {
+		ERROR("Invalid argument mask");
+		return -1;
+	}
+
 	op = parse_v2_rule_op(s);
 	if (op == _SCMP_CMP_MAX) {
 		ERROR("Failed to interpret args operator value");

src/lxc/utils.c

@@ -1958,6 +1958,29 @@ int lxc_safe_ulong(const char *numstr, unsigned long *converted)
 	return 0;
 }
 
+int lxc_safe_uint64(const char *numstr, uint64_t *converted)
+{
+	char *err = NULL;
+	uint64_t u;
+
+	while (isspace(*numstr))
+		numstr++;
+
+	if (*numstr == '-')
+		return -EINVAL;
+
+	errno = 0;
+	u = strtoull(numstr, &err, 0);
+	if (errno == ERANGE && u == ULLONG_MAX)
+		return -ERANGE;
+
+	if (err == numstr || *err != '\0')
+		return -EINVAL;
+
+	*converted = u;
+	return 0;
+}
+
 int lxc_safe_int(const char *numstr, int *converted)
 {
 	char *err = NULL;

src/lxc/utils.h

@@ -530,6 +530,7 @@ extern int lxc_safe_int(const char *numstr, int *converted);
 extern int lxc_safe_long(const char *numstr, long int *converted);
 extern int lxc_safe_long_long(const char *numstr, long long int *converted);
 extern int lxc_safe_ulong(const char *numstr, unsigned long *converted);
+extern int lxc_safe_uint64(const char *numstr, uint64_t *converted);
 /* Handles B, kb, MB, GB. Detects overflows and reports -ERANGE. */
 extern int parse_byte_size_string(const char *s, int64_t *converted);