From 25f7136d326753cb0bb7612a98db6542c9fdc3bd Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Thu, 2 Feb 2023 15:22:52 +0100
Subject: last: sync utmp strings use with upstream code
Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=2160321
Signed-off-by: Karel Zak <kzak@redhat.com>
---
include/strutils.h | 30 +++++++++++++++++++
include/timeutils.h | 1 +
login-utils/last.c | 73 +++++++++++++++++++++++----------------------
3 files changed, 69 insertions(+), 35 deletions(-)
diff --git a/include/strutils.h b/include/strutils.h
index 5d07fcc7c..193f1acbc 100644
--- a/include/strutils.h
+++ b/include/strutils.h
@@ -65,6 +65,36 @@ static inline void xstrncpy(char *dest, const char *src, size_t n)
dest[n-1] = 0;
}
+/* This is like strncpy(), but based on memcpy(), so compilers and static
+ * analyzers do not complain when sizeof(destination) is the same as 'n' and
+ * result is not terminated by zero.
+ *
+ * Use this function to copy string to logs with fixed sizes (wtmp/utmp. ...)
+ * where string terminator is optional.
+ */
+static inline void * __attribute__((nonnull (1)))
+str2memcpy(void *dest, const char *src, size_t n)
+{
+ size_t bytes = strlen(src) + 1;
+
+ if (bytes > n)
+ bytes = n;
+
+ memcpy(dest, src, bytes);
+ return dest;
+}
+
+static inline char * __attribute__((nonnull (1)))
+mem2strcpy(char *dest, const void *src, size_t n, size_t nmax)
+{
+ if (n + 1 > nmax)
+ n = nmax - 1;
+
+ memset(dest, '\0', nmax);
+ memcpy(dest, src, n);
+ return dest;
+}
+
static inline int strdup_to_offset(void *stru, size_t offset, const char *str)
{
char *n = NULL;
diff --git a/include/timeutils.h b/include/timeutils.h
index 230e6db5f..f1540a183 100644
--- a/include/timeutils.h
+++ b/include/timeutils.h
@@ -74,6 +74,7 @@ enum {
ISO_TIMESTAMP_COMMA_GT = ISO_TIMESTAMP_COMMA_G | ISO_T
};
+#define CTIME_BUFSIZ 26
#define ISO_BUFSIZ 42
int strtimeval_iso(struct timeval *tv, int flags, char *buf, size_t bufsz);
diff --git a/login-utils/last.c b/login-utils/last.c
index 80d77d20b..8f7c36984 100644
--- a/login-utils/last.c
+++ b/login-utils/last.c
@@ -339,15 +339,22 @@ static int time_formatter(int fmt, char *dst, size_t dlen, time_t *when)
break;
case LAST_TIMEFTM_HHMM:
{
- struct tm *tm = localtime(when);
- if (!snprintf(dst, dlen, "%02d:%02d", tm->tm_hour, tm->tm_min))
+ struct tm tm;
+
+ localtime_r(when, &tm);
+ if (!snprintf(dst, dlen, "%02d:%02d", tm.tm_hour, tm.tm_min))
ret = -1;
break;
}
case LAST_TIMEFTM_CTIME:
- snprintf(dst, dlen, "%s", ctime(when));
+ {
+ char buf[CTIME_BUFSIZ];
+
+ ctime_r(when, buf);
+ snprintf(dst, dlen, "%s", buf);
ret = rtrim_whitespace((unsigned char *) dst);
break;
+ }
case LAST_TIMEFTM_ISO8601:
ret = strtime_iso(when, ISO_TIMESTAMP_T, dst, dlen);
break;
@@ -394,8 +401,7 @@ static int list(const struct last_control *ctl, struct utmpx *p, time_t logout_t
/*
* uucp and ftp have special-type entries
*/
- utline[0] = 0;
- strncat(utline, p->ut_line, sizeof(p->ut_line));
+ mem2strcpy(utline, p->ut_line, sizeof(p->ut_line), sizeof(utline));
if (strncmp(utline, "ftp", 3) == 0 && isdigit(utline[3]))
utline[3] = 0;
if (strncmp(utline, "uucp", 4) == 0 && isdigit(utline[4]))
@@ -447,48 +453,48 @@ static int list(const struct last_control *ctl, struct utmpx *p, time_t logout_t
if (logout_time == currentdate) {
if (ctl->time_fmt > LAST_TIMEFTM_SHORT) {
- sprintf(logouttime, " still running");
+ snprintf(logouttime, sizeof(logouttime), " still running");
length[0] = 0;
} else {
- sprintf(logouttime, " still");
- sprintf(length, "running");
+ snprintf(logouttime, sizeof(logouttime), " still");
+ snprintf(length, sizeof(length), "running");
}
} else if (days) {
- sprintf(length, "(%d+%02d:%02d)", days, abs(hours), abs(mins)); /* hours and mins always shown as positive (w/o minus sign!) even if secs < 0 */
+ snprintf(length, sizeof(length), "(%d+%02d:%02d)", days, abs(hours), abs(mins)); /* hours and mins always shown as positive (w/o minus sign!) even if secs < 0 */
} else if (hours) {
- sprintf(length, " (%02d:%02d)", hours, abs(mins)); /* mins always shown as positive (w/o minus sign!) even if secs < 0 */
+ snprintf(length, sizeof(length), " (%02d:%02d)", hours, abs(mins)); /* mins always shown as positive (w/o minus sign!) even if secs < 0 */
} else if (secs >= 0) {
- sprintf(length, " (%02d:%02d)", hours, mins);
+ snprintf(length, sizeof(length), " (%02d:%02d)", hours, mins);
} else {
- sprintf(length, " (-00:%02d)", abs(mins)); /* mins always shown as positive (w/o minus sign!) even if secs < 0 */
+ snprintf(length, sizeof(length), " (-00:%02d)", abs(mins)); /* mins always shown as positive (w/o minus sign!) even if secs < 0 */
}
switch(what) {
case R_CRASH:
- sprintf(logouttime, "- crash");
+ snprintf(logouttime, sizeof(logouttime), "- crash");
break;
case R_DOWN:
- sprintf(logouttime, "- down ");
+ snprintf(logouttime, sizeof(logouttime), "- down ");
break;
case R_NOW:
if (ctl->time_fmt > LAST_TIMEFTM_SHORT) {
- sprintf(logouttime, " still logged in");
+ snprintf(logouttime, sizeof(logouttime), " still logged in");
length[0] = 0;
} else {
- sprintf(logouttime, " still");
- sprintf(length, "logged in");
+ snprintf(logouttime, sizeof(logouttime), " still");
+ snprintf(length, sizeof(length), "logged in");
}
break;
case R_PHANTOM:
if (ctl->time_fmt > LAST_TIMEFTM_SHORT) {
- sprintf(logouttime, " gone - no logout");
+ snprintf(logouttime, sizeof(logouttime), " gone - no logout");
length[0] = 0;
} else if (ctl->time_fmt == LAST_TIMEFTM_SHORT) {
- sprintf(logouttime, " gone");
- sprintf(length, "- no logout");
+ snprintf(logouttime, sizeof(logouttime), " gone");
+ snprintf(length, sizeof(length), "- no logout");
} else {
logouttime[0] = 0;
- sprintf(length, "no logout");
+ snprintf(length, sizeof(length), "no logout");
}
break;
case R_TIMECHANGE:
@@ -508,15 +514,8 @@ static int list(const struct last_control *ctl, struct utmpx *p, time_t logout_t
r = -1;
if (ctl->usedns || ctl->useip)
r = dns_lookup(domain, sizeof(domain), ctl->useip, (int32_t*)p->ut_addr_v6);
- if (r < 0) {
- size_t sz = sizeof(p->ut_host);
-
- if (sz > sizeof(domain))
- sz = sizeof(domain);
-
- xstrncpy(domain, p->ut_host, sz);
- }
-
+ if (r < 0)
+ mem2strcpy(domain, p->ut_host, sizeof(p->ut_host), sizeof(domain));
if (ctl->showhost) {
if (!ctl->altlist) {
@@ -607,10 +606,11 @@ static int is_phantom(const struct last_control *ctl, struct utmpx *ut)
if (ut->ut_tv.tv_sec < ctl->boot_time.tv_sec)
return 1;
+ ut->ut_user[sizeof(ut->ut_user) - 1] = '\0';
pw = getpwnam(ut->ut_user);
if (!pw)
return 1;
- sprintf(path, "/proc/%u/loginuid", ut->ut_pid);
+ snprintf(path, sizeof(path), "/proc/%u/loginuid", ut->ut_pid);
if (access(path, R_OK) == 0) {
unsigned int loginuid;
FILE *f = NULL;
@@ -624,8 +624,11 @@ static int is_phantom(const struct last_control *ctl, struct utmpx *ut)
return 1;
} else {
struct stat st;
+ char utline[sizeof(ut->ut_line) + 1];
+
+ mem2strcpy(utline, ut->ut_line, sizeof(ut->ut_line), sizeof(utline));
- sprintf(path, "/dev/%s", ut->ut_line);
+ snprintf(path, sizeof(path), "/dev/%s", utline);
if (stat(path, &st))
return 1;
if (pw->pw_uid != st.st_uid)
@@ -736,7 +739,7 @@ static void process_wtmp_file(const struct last_control *ctl,
else {
if (ut.ut_type != DEAD_PROCESS &&
ut.ut_user[0] && ut.ut_line[0] &&
- strcmp(ut.ut_user, "LOGIN") != 0)
+ strncmp(ut.ut_user, "LOGIN", 5) != 0)
ut.ut_type = USER_PROCESS;
/*
* Even worse, applications that write ghost
@@ -749,7 +752,7 @@ static void process_wtmp_file(const struct last_control *ctl,
/*
* Clock changes.
*/
- if (strcmp(ut.ut_user, "date") == 0) {
+ if (strncmp(ut.ut_user, "date", 4) == 0) {
if (ut.ut_line[0] == '|')
ut.ut_type = OLD_TIME;
if (ut.ut_line[0] == '{')
@@ -784,7 +787,7 @@ static void process_wtmp_file(const struct last_control *ctl,
case RUN_LVL:
x = ut.ut_pid & 255;
if (ctl->extended) {
- sprintf(ut.ut_line, "(to lvl %c)", x);
+ snprintf(ut.ut_line, sizeof(ut.ut_line), "(to lvl %c)", x);
quit = list(ctl, &ut, lastrch, R_NORMAL);
}
if (x == '0' || x == '6') {
--
2.39.1