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-rw-r--r--lib/sgetpwent.c109
1 files changed, 109 insertions, 0 deletions
diff --git a/lib/sgetpwent.c b/lib/sgetpwent.c
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+/*
+ * SPDX-FileCopyrightText: 1989 - 1994, Julianne Frances Haugh
+ * SPDX-FileCopyrightText: 1996 - 1998, Marek Michałkiewicz
+ * SPDX-FileCopyrightText: 2003 - 2005, Tomasz Kłoczko
+ * SPDX-FileCopyrightText: 2008 , Nicolas François
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <config.h>
+
+#ident "$Id$"
+
+#include <sys/types.h>
+#include "defines.h"
+#include <stdio.h>
+#include <pwd.h>
+#include "prototypes.h"
+#include "shadowlog_internal.h"
+
+#define NFIELDS 7
+
+/*
+ * sgetpwent - convert a string to a (struct passwd)
+ *
+ * sgetpwent() parses a string into the parts required for a password
+ * structure. Strict checking is made for the UID and GID fields and
+ * presence of the correct number of colons. Any failing tests result
+ * in a NULL pointer being returned.
+ *
+ * NOTE: This function uses hard-coded string scanning functions for
+ * performance reasons. I am going to come up with some conditional
+ * compilation glarp to improve on this in the future.
+ */
+struct passwd *sgetpwent (const char *buf)
+{
+ static struct passwd pwent;
+ static char pwdbuf[PASSWD_ENTRY_MAX_LENGTH];
+ int i;
+ char *cp;
+ char *fields[NFIELDS];
+
+ /*
+ * Copy the string to a static buffer so the pointers into
+ * the password structure remain valid.
+ */
+
+ if (strlen (buf) >= sizeof pwdbuf) {
+ fprintf (shadow_logfd,
+ "%s: Too long passwd entry encountered, file corruption?\n",
+ shadow_progname);
+ return 0; /* fail if too long */
+ }
+ strcpy (pwdbuf, buf);
+
+ /*
+ * Save a pointer to the start of each colon separated
+ * field. The fields are converted into NUL terminated strings.
+ */
+
+ for (cp = pwdbuf, i = 0; (i < NFIELDS) && (NULL != cp); i++) {
+ fields[i] = cp;
+ while (('\0' != *cp) && (':' != *cp)) {
+ cp++;
+ }
+
+ if ('\0' != *cp) {
+ *cp = '\0';
+ cp++;
+ } else {
+ cp = NULL;
+ }
+ }
+
+ /* something at the end, columns over shot */
+ if ( cp != NULL ) {
+ return( NULL );
+ }
+
+ /*
+ * There must be exactly NFIELDS colon separated fields or
+ * the entry is invalid. Also, the UID and GID must be non-blank.
+ */
+
+ if (i != NFIELDS || *fields[2] == '\0' || *fields[3] == '\0')
+ return NULL;
+
+ /*
+ * Each of the fields is converted the appropriate data type
+ * and the result assigned to the password structure. If the
+ * UID or GID does not convert to an integer value, a NULL
+ * pointer is returned.
+ */
+
+ pwent.pw_name = fields[0];
+ pwent.pw_passwd = fields[1];
+ if (get_uid (fields[2], &pwent.pw_uid) == 0) {
+ return NULL;
+ }
+ if (get_gid (fields[3], &pwent.pw_gid) == 0) {
+ return NULL;
+ }
+ pwent.pw_gecos = fields[4];
+ pwent.pw_dir = fields[5];
+ pwent.pw_shell = fields[6];
+
+ return &pwent;
+}
+