mirrors/glibc
1
0
Fork 0
mirror of https://sourceware.org/git/glibc.git synced 2024-11-23 09:43:32 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

login: Remove utmp backend jump tables [BZ #23518]

Browse Source 
There is just one file-based implementation, so this dispatch
mechanism is unnecessary.  Instead of the vtable pointer
__libc_utmp_jump_table, use a non-negative file_fd as the indicator
that the backend is initialized.

(cherry picked from commit 1a7fe2ebe5)
This commit is contained in:
Florian Weimer 2019-08-05 15:54:10 +02:00
parent 50f20fe506
commit b90aefd4ac
11 changed files with 106 additions and 197 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
ChangeLog
View File

@ -1,3 +1,43 @@
2019-08-05 Florian Weimer <fweimer@redhat.com>
[BZ #23518]
* login/uptmp-private.h (struct ufuncs): Remove definition.
(__libc_utmp_file_functions, __libc_utmp_unknown_functions)
(__libc_utmp_jump_table): Remove declarations.
(__libc_setutent, __libc_getutent_r, __libc_getutid_r)
(__libc_getutline_r, __libc_pututline, __libc_endutent)
(__libc_updwtmp): Declare.
* login/getutent_r.c (__libc_utmp_unknown_functions)
(__libc_utmp_jump_table, setutent_unknown, getutent_r_unknown)
(getutid_r_unknown, getutline_r_unknown, pututline_unknown)
(endutent_unknown): Remove definitions.
(__setutent): Call __libc_setutent.
(__getutent_r): Call __libc_getutent_r.
(__pututline): Call __libc_pututline.
(__endutent): Call __libc_endutent.
* login/getutid_r.c (__getutid_r): Call __libc_getutid_r.
* login/getutline_r.c (__getutline_r): Call __libc_getutline_r.
* login/updwtmp.c (__updwtmp): Call __libc_updwtmp.
* login/utmp_file.c (__libc_utmp_file_functions): Remove definition
(__libc_setutent): Rename from stetutent_file. Drop static.
(maybe_setutent): New function.
(__libc_getutent_r): Rename from getutent_r_file. Drop static.
Check for initialization.
(__libc_getutid_r): Rename from getutid_r_file. Drop static.
Check for initialization.
(__libc_getutline_r): Rename from getutline_r_file. Drop static.
Check for initialization.
(__libc_pututline): Rename from pututline_file. Drop static.
Check for initialization.
(__libc_endutent): Rename from endutent_file. Drop static. Check
for initialization.
(__libc_updwtmp): Rename from updwtmp_file. Drop static.
* login/utmpname.c (__utmpname): Call __libc_endutent.
* sysdeps/unix/getlogin_r (__getlogin_r): Call __libc_setutent,
__libc_getutlien_r, __libc_endutent.
* manual/users.texi (Who Logged In, Manipulating the Database):
Adjust.
2019-08-15 Florian Weimer <fweimer@redhat.com>
* malloc/Makefile (tests): Only add tst-mxfast for

1
NEWS
View File

@ -17,6 +17,7 @@ CVE-2019-19126: ld.so failed to ignore the LD_PREFER_MAP_32BIT_EXEC
The following bugs are resolved with this release:
[23518] login: Remove utmp backend jump tables
[24682] localedata: zh_CN first weekday should be Monday per GB/T
7408-2005
[24867] malloc: Remove unwanted leading whitespace in malloc_info

108
login/getutent_r.c
View File

@ -23,115 +23,16 @@
#include "utmp-private.h"
/* Functions defined here. */
static int setutent_unknown (void);
static int getutent_r_unknown (struct utmp *buffer, struct utmp **result);
static int getutid_r_unknown (const struct utmp *line, struct utmp *buffer,
struct utmp **result);
static int getutline_r_unknown (const struct utmp *id, struct utmp *buffer,
struct utmp **result);
static struct utmp *pututline_unknown (const struct utmp *data);
static void endutent_unknown (void);
/* Initial Jump table. */
const struct utfuncs __libc_utmp_unknown_functions =
{
setutent_unknown,
getutent_r_unknown,
getutid_r_unknown,
getutline_r_unknown,
pututline_unknown,
endutent_unknown,
NULL
};
/* Currently selected backend. */
const struct utfuncs *__libc_utmp_jump_table = &__libc_utmp_unknown_functions;
/* We need to protect the opening of the file. */
__libc_lock_define_initialized (, __libc_utmp_lock attribute_hidden)
static int
setutent_unknown (void)
{
int result;
result = (*__libc_utmp_file_functions.setutent) ();
if (result)
__libc_utmp_jump_table = &__libc_utmp_file_functions;
return result;
}
static int
getutent_r_unknown (struct utmp *buffer, struct utmp **result)
{
/* The backend was not yet initialized. */
if (setutent_unknown ())
return (*__libc_utmp_jump_table->getutent_r) (buffer, result);
/* Not available. */
*result = NULL;
return -1;
}
static int
getutid_r_unknown (const struct utmp *id, struct utmp *buffer,
struct utmp **result)
{
/* The backend was not yet initialized. */
if (setutent_unknown ())
return (*__libc_utmp_jump_table->getutid_r) (id, buffer, result);
/* Not available. */
*result = NULL;
return -1;
}
static int
getutline_r_unknown (const struct utmp *line, struct utmp *buffer,
struct utmp **result)
{
/* The backend was not yet initialized. */
if (setutent_unknown ())
return (*__libc_utmp_jump_table->getutline_r) (line, buffer, result);
/* Not available. */
*result = NULL;
return -1;
}
static struct utmp *
pututline_unknown (const struct utmp *data)
{
/* The backend was not yet initialized. */
if (setutent_unknown ())
return (*__libc_utmp_jump_table->pututline) (data);
/* Not available. */
return NULL;
}
static void
endutent_unknown (void)
{
/* Nothing to do. */
}
void
__setutent (void)
{
__libc_lock_lock (__libc_utmp_lock);
(*__libc_utmp_jump_table->setutent) ();
__libc_setutent ();
__libc_lock_unlock (__libc_utmp_lock);
}
@ -145,7 +46,7 @@ __getutent_r (struct utmp *buffer, struct utmp **result)
__libc_lock_lock (__libc_utmp_lock);
retval = (*__libc_utmp_jump_table->getutent_r) (buffer, result);
retval = __libc_getutent_r (buffer, result);
__libc_lock_unlock (__libc_utmp_lock);
@ -162,7 +63,7 @@ __pututline (const struct utmp *data)
__libc_lock_lock (__libc_utmp_lock);
buffer = (*__libc_utmp_jump_table->pututline) (data);
buffer = __libc_pututline (data);
__libc_lock_unlock (__libc_utmp_lock);
@ -177,8 +78,7 @@ __endutent (void)
{
__libc_lock_lock (__libc_utmp_lock);
(*__libc_utmp_jump_table->endutent) ();
__libc_utmp_jump_table = &__libc_utmp_unknown_functions;
__libc_endutent ();
__libc_lock_unlock (__libc_utmp_lock);
}

2
login/getutid_r.c
View File

@ -49,7 +49,7 @@ __getutid_r (const struct utmp *id, struct utmp *buffer, struct utmp **result)
__libc_lock_lock (__libc_utmp_lock);
retval = (*__libc_utmp_jump_table->getutid_r) (id, buffer, result);
retval = __libc_getutid_r (id, buffer, result);
__libc_lock_unlock (__libc_utmp_lock);

2
login/getutline_r.c
View File

@ -36,7 +36,7 @@ __getutline_r (const struct utmp *line, struct utmp *buffer,
__libc_lock_lock (__libc_utmp_lock);
retval = (*__libc_utmp_jump_table->getutline_r) (line, buffer, result);
retval = __libc_getutline_r (line, buffer, result);
__libc_lock_unlock (__libc_utmp_lock);

2
login/updwtmp.c
View File

@ -29,7 +29,7 @@ __updwtmp (const char *wtmp_file, const struct utmp *utmp)
{
const char *file_name = TRANSFORM_UTMP_FILE_NAME (wtmp_file);
(*__libc_utmp_file_functions.updwtmp) (file_name, utmp);
__libc_updwtmp (file_name, utmp);
}
libc_hidden_def (__updwtmp)
weak_alias (__updwtmp, updwtmp)

29
login/utmp-private.h
View File

@ -24,24 +24,17 @@
#include <utmp.h>
#include <libc-lock.h>
/* The structure describing the functions in a backend. */
struct utfuncs
{
int (*setutent) (void);
int (*getutent_r) (struct utmp *, struct utmp **);
int (*getutid_r) (const struct utmp *, struct utmp *, struct utmp **);
int (*getutline_r) (const struct utmp *, struct utmp *, struct utmp **);
struct utmp *(*pututline) (const struct utmp *);
void (*endutent) (void);
int (*updwtmp) (const char *, const struct utmp *);
};
/* The tables from the services. */
extern const struct utfuncs __libc_utmp_file_functions attribute_hidden;
extern const struct utfuncs __libc_utmp_unknown_functions attribute_hidden;
/* Currently selected backend. */
extern const struct utfuncs *__libc_utmp_jump_table attribute_hidden;
/* These functions check for initialization, but not perform any
locking. */
int __libc_setutent (void) attribute_hidden;
int __libc_getutent_r (struct utmp *, struct utmp **) attribute_hidden;
int __libc_getutid_r (const struct utmp *, struct utmp *, struct utmp **)
attribute_hidden;
int __libc_getutline_r (const struct utmp *, struct utmp *, struct utmp **)
attribute_hidden;
struct utmp *__libc_pututline (const struct utmp *) attribute_hidden;
void __libc_endutent (void) attribute_hidden;
int __libc_updwtmp (const char *, const struct utmp *) attribute_hidden;
/* Current file name. */
extern const char *__libc_utmp_file_name attribute_hidden;

89
login/utmp_file.c
View File

@ -105,37 +105,12 @@ static void timeout_handler (int signum) {};
alarm (old_timeout); \
} while (0)
/* Functions defined here. */
static int setutent_file (void);
static int getutent_r_file (struct utmp *buffer, struct utmp **result);
static int getutid_r_file (const struct utmp *key, struct utmp *buffer,
struct utmp **result);
static int getutline_r_file (const struct utmp *key, struct utmp *buffer,
struct utmp **result);
static struct utmp *pututline_file (const struct utmp *data);
static void endutent_file (void);
static int updwtmp_file (const char *file, const struct utmp *utmp);
/* Jump table for file functions. */
const struct utfuncs __libc_utmp_file_functions =
{
setutent_file,
getutent_r_file,
getutid_r_file,
getutline_r_file,
pututline_file,
endutent_file,
updwtmp_file
};
#ifndef TRANSFORM_UTMP_FILE_NAME
# define TRANSFORM_UTMP_FILE_NAME(file_name) (file_name)
#endif
static int
setutent_file (void)
int
__libc_setutent (void)
{
if (file_fd < 0)
{
@ -166,15 +141,19 @@ setutent_file (void)
return 1;
}
/* Preform initialization if necessary. */
static bool
maybe_setutent (void)
{
return file_fd >= 0 || __libc_setutent ();
}
static int
getutent_r_file (struct utmp *buffer, struct utmp **result)
int
__libc_getutent_r (struct utmp *buffer, struct utmp **result)
{
ssize_t nbytes;
assert (file_fd >= 0);
if (file_offset == -1l)
if (!maybe_setutent () || file_offset == -1l)
{
/* Not available. */
*result = NULL;
@ -279,13 +258,11 @@ unlock_return:
/* For implementing this function we don't use the getutent_r function
because we can avoid the reposition on every new entry this way. */
static int
getutid_r_file (const struct utmp *id, struct utmp *buffer,
struct utmp **result)
int
__libc_getutid_r (const struct utmp *id, struct utmp *buffer,
struct utmp **result)
{
assert (file_fd >= 0);
if (file_offset == -1l)
if (!maybe_setutent () || file_offset == -1l)
{
*result = NULL;
return -1;
@ -309,13 +286,11 @@ getutid_r_file (const struct utmp *id, struct utmp *buffer,
/* For implementing this function we don't use the getutent_r function
because we can avoid the reposition on every new entry this way. */
static int
getutline_r_file (const struct utmp *line, struct utmp *buffer,
struct utmp **result)
int
__libc_getutline_r (const struct utmp *line, struct utmp *buffer,
struct utmp **result)
{
assert (file_fd >= 0);
if (file_offset == -1l)
if (!maybe_setutent () || file_offset == -1l)
{
*result = NULL;
return -1;
@ -361,15 +336,16 @@ unlock_return:
}
static struct utmp *
pututline_file (const struct utmp *data)
struct utmp *
__libc_pututline (const struct utmp *data)
{
if (!maybe_setutent ())
return NULL;
struct utmp buffer;
struct utmp *pbuf;
int found;
assert (file_fd >= 0);
if (! file_writable)
{
/* We must make the file descriptor writable before going on. */
@ -467,18 +443,19 @@ pututline_file (const struct utmp *data)
}
static void
endutent_file (void)
void
__libc_endutent (void)
{
assert (file_fd >= 0);
__close_nocancel_nostatus (file_fd);
file_fd = -1;
if (file_fd >= 0)
{
__close_nocancel_nostatus (file_fd);
file_fd = -1;
}
}
static int
updwtmp_file (const char *file, const struct utmp *utmp)
int
__libc_updwtmp (const char *file, const struct utmp *utmp)
{
int result = -1;
off64_t offset;

3
login/utmpname.c
View File

@ -42,8 +42,7 @@ __utmpname (const char *file)
__libc_lock_lock (__libc_utmp_lock);
/* Close the old file. */
(*__libc_utmp_jump_table->endutent) ();
__libc_utmp_jump_table = &__libc_utmp_unknown_functions;
__libc_endutent ();
if (strcmp (file, __libc_utmp_file_name) != 0)
{

20
manual/users.texi
View File

@ -894,9 +894,9 @@ The @code{getlogin} function is declared in @file{unistd.h}, while
@c ttyname_r dup @ascuheap @acsmem @acsfd
@c strncpy dup ok
@c libc_lock_lock dup @asulock @aculock
@c *libc_utmp_jump_table->setutent dup @mtasurace:utent @acsfd
@c *libc_utmp_jump_table->getutline_r dup @mtasurace:utent @mtascusig:ALRM @mtascutimer
@c *libc_utmp_jump_table->endutent dup @mtasurace:utent @asulock @aculock
@c __libc_setutent dup @mtasurace:utent @acsfd
@c __libc_getutline_r dup @mtasurace:utent @mtascusig:ALRM @mtascutimer
@c __libc_endutent dup @mtasurace:utent @asulock @aculock
@c libc_lock_unlock dup ok
@c strlen dup ok
@c memcpy dup ok
@ -1111,7 +1111,7 @@ compatibility only, @file{utmp.h} defines @code{ut_time} as an alias for
@c setutent @mtasurace:utent @asulock @aculock @acsfd
@c libc_lock_lock dup @asulock @aculock
@c *libc_utmp_jump_table->setutent @mtasurace:utent @acsfd
@c __libc_setutent @mtasurace:utent @acsfd
@c setutent_unknown @mtasurace:utent @acsfd
@c *libc_utmp_file_functions.setutent = setutent_file @mtasurace:utent @acsfd
@c open_not_cancel_2 dup @acsfd
@ -1152,7 +1152,7 @@ A null pointer is returned in case no further entry is available.
@safety{@prelim{}@mtunsafe{@mtasurace{:utent}}@asunsafe{@asulock{}}@acunsafe{@aculock{} @acsfd{}}}
@c endutent @mtasurace:utent @asulock @aculock @acsfd
@c libc_lock_lock dup @asulock @aculock
@c *libc_utmp_jump_table->endutent @mtasurace:utent @acsfd
@c __libc_endutent @mtasurace:utent @acsfd
@c endutent_unknown ok
@c endutent_file @mtasurace:utent @acsfd
@c close_not_cancel_no_status dup @acsfd
@ -1230,7 +1230,7 @@ over again.
@safety{@prelim{}@mtunsafe{@mtasurace{:utent} @mtascusig{:ALRM} @mtascutimer{}}@asunsafe{@asulock{}}@acunsafe{@aculock{} @acsfd{}}}
@c pututline @mtasurace:utent @mtascusig:ALRM @mtascutimer @asulock @aculock @acsfd
@c libc_lock_lock dup @asulock @aculock
@c *libc_utmp_jump_table->pututline @mtasurace:utent @mtascusig:ALRM @mtascutimer @acsfd
@c __libc_pututline @mtasurace:utent @mtascusig:ALRM @mtascutimer @acsfd
@c pututline_unknown @mtasurace:utent @acsfd
@c setutent_unknown dup @mtasurace:utent @acsfd
@c pututline_file @mtascusig:ALRM @mtascutimer @acsfd
@ -1282,7 +1282,7 @@ user-provided buffer.
@safety{@prelim{}@mtunsafe{@mtasurace{:utent} @mtascusig{:ALRM} @mtascutimer{}}@asunsafe{@asulock{}}@acunsafe{@aculock{} @acsfd{}}}
@c getutent_r @mtasurace:utent @mtascusig:ALRM @mtascutimer @asulock @aculock @acsfd
@c libc_lock_lock dup @asulock @aculock
@c *libc_utmp_jump_table->getutent_r @mtasurace:utent @mtascusig:ALRM @mtascutimer @acsfd
@c __libc_getutent_r @mtasurace:utent @mtascusig:ALRM @mtascutimer @acsfd
@c getutent_r_unknown @mtasurace:utent @acsfd
@c setutent_unknown dup @mtasurace:utent @acsfd
@c getutent_r_file @mtasurace:utent @mtascusig:ALRM @mtascutimer
@ -1319,7 +1319,7 @@ This function is a GNU extension.
@safety{@prelim{}@mtunsafe{@mtasurace{:utent} @mtascusig{:ALRM} @mtascutimer{}}@asunsafe{@asulock{}}@acunsafe{@aculock{} @acsfd{}}}
@c getutid_r @mtasurace:utent @mtascusig:ALRM @mtascutimer @asulock @aculock @acsfd
@c libc_lock_lock dup @asulock @aculock
@c *libc_utmp_jump_table->getutid_r @mtasurace:utent @mtascusig:ALRM @mtascutimer @acsfd
@c __libc_getutid_r @mtasurace:utent @mtascusig:ALRM @mtascutimer @acsfd
@c getutid_r_unknown @mtasurace:utent @acsfd
@c setutent_unknown dup @mtasurace:utent @acsfd
@c getutid_r_file @mtascusig:ALRM @mtascutimer
@ -1349,7 +1349,7 @@ This function is a GNU extension.
@safety{@prelim{}@mtunsafe{@mtasurace{:utent} @mtascusig{:ALRM} @mtascutimer{}}@asunsafe{@asulock{}}@acunsafe{@aculock{} @acsfd{}}}
@c getutline_r @mtasurace:utent @mtascusig:ALRM @mtascutimer @asulock @aculock @acsfd
@c libc_lock_lock dup @asulock @aculock
@c *libc_utmp_jump_table->getutline_r @mtasurace:utent @mtascusig:ALRM @mtascutimer @acsfd
@c __libc_getutline_r @mtasurace:utent @mtascusig:ALRM @mtascutimer @acsfd
@c getutline_r_unknown @mtasurace:utent @acsfd
@c setutent_unknown dup @mtasurace:utent @acsfd
@c getutline_r_file @mtasurace:utent @mtascusig:ALRM @mtascutimer
@ -1393,7 +1393,7 @@ be used.
@safety{@prelim{}@mtunsafe{@mtasurace{:utent}}@asunsafe{@asulock{} @ascuheap{}}@acunsafe{@aculock{} @acsmem{}}}
@c utmpname @mtasurace:utent @asulock @ascuheap @aculock @acsmem
@c libc_lock_lock dup @asulock @aculock
@c *libc_utmp_jump_table->endutent dup @mtasurace:utent
@c __libc_endutent dup @mtasurace:utent
@c strcmp dup ok
@c free dup @ascuheap @acsmem
@c strdup dup @ascuheap @acsmem

7
sysdeps/unix/getlogin_r.c
View File

@ -64,8 +64,8 @@ __getlogin_r (char *name, size_t name_len)
held so that our search is thread-safe. */
__libc_lock_lock (__libc_utmp_lock);
(*__libc_utmp_jump_table->setutent) ();
result = (*__libc_utmp_jump_table->getutline_r) (&line, &buffer, &ut);
__libc_setutent ();
result = __libc_getutline_r (&line, &buffer, &ut);
if (result < 0)
{
if (errno == ESRCH)
@ -74,8 +74,7 @@ __getlogin_r (char *name, size_t name_len)
else
result = errno;
}
(*__libc_utmp_jump_table->endutent) ();
__libc_utmp_jump_table = &__libc_utmp_unknown_functions;
__libc_endutent ();
__libc_lock_unlock (__libc_utmp_lock);
if (result == 0)