16afe18142
Moreover, include checks to prevent writing entries longer than the length limit. Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1422497 Signed-off-by: Tomáš Mráz <tm@t8m.info> Signed-off-by: Iker Pedrosa <ipedrosa@redhat.com>
110 lines
2.6 KiB
C
110 lines
2.6 KiB
C
/*
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* SPDX-FileCopyrightText: 1989 - 1994, Julianne Frances Haugh
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* SPDX-FileCopyrightText: 1996 - 1998, Marek Michałkiewicz
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* SPDX-FileCopyrightText: 2003 - 2005, Tomasz Kłoczko
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* SPDX-FileCopyrightText: 2008 , Nicolas François
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include <config.h>
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#ident "$Id$"
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#include <sys/types.h>
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#include "defines.h"
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#include <stdio.h>
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#include <pwd.h>
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#include "prototypes.h"
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#include "shadowlog_internal.h"
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#define NFIELDS 7
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/*
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* sgetpwent - convert a string to a (struct passwd)
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*
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* sgetpwent() parses a string into the parts required for a password
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* structure. Strict checking is made for the UID and GID fields and
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* presence of the correct number of colons. Any failing tests result
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* in a NULL pointer being returned.
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*
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* NOTE: This function uses hard-coded string scanning functions for
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* performance reasons. I am going to come up with some conditional
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* compilation glarp to improve on this in the future.
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*/
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struct passwd *sgetpwent (const char *buf)
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{
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static struct passwd pwent;
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static char pwdbuf[PASSWD_ENTRY_MAX_LENGTH];
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int i;
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char *cp;
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char *fields[NFIELDS];
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/*
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* Copy the string to a static buffer so the pointers into
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* the password structure remain valid.
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*/
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if (strlen (buf) >= sizeof pwdbuf) {
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fprintf (shadow_logfd,
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"%s: Too long passwd entry encountered, file corruption?\n",
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shadow_progname);
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return 0; /* fail if too long */
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}
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strcpy (pwdbuf, buf);
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/*
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* Save a pointer to the start of each colon separated
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* field. The fields are converted into NUL terminated strings.
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*/
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for (cp = pwdbuf, i = 0; (i < NFIELDS) && (NULL != cp); i++) {
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fields[i] = cp;
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while (('\0' != *cp) && (':' != *cp)) {
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cp++;
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}
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if ('\0' != *cp) {
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*cp = '\0';
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cp++;
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} else {
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cp = NULL;
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}
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}
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/* something at the end, columns over shot */
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if ( cp != NULL ) {
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return( NULL );
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}
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/*
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* There must be exactly NFIELDS colon separated fields or
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* the entry is invalid. Also, the UID and GID must be non-blank.
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*/
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if (i != NFIELDS || *fields[2] == '\0' || *fields[3] == '\0')
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return NULL;
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/*
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* Each of the fields is converted the appropriate data type
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* and the result assigned to the password structure. If the
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* UID or GID does not convert to an integer value, a NULL
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* pointer is returned.
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*/
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pwent.pw_name = fields[0];
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pwent.pw_passwd = fields[1];
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if (get_uid (fields[2], &pwent.pw_uid) == 0) {
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return NULL;
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}
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if (get_gid (fields[3], &pwent.pw_gid) == 0) {
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return NULL;
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}
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pwent.pw_gecos = fields[4];
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pwent.pw_dir = fields[5];
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pwent.pw_shell = fields[6];
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return &pwent;
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}
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