On systems with Linux kernel < 3.17, getentropy() and getrandom() may
exist but return ENOSYS. Use /dev/urandom as a fallback to avoid a hard
requirement on Linux kernel version.
Fixes#512.
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
In order to remove some of the FIXMEs it was necessary to change the
code and call getulong() instead of getlong().
Signed-off-by: Iker Pedrosa <ipedrosa@redhat.com>
C89 and POSIX.1-2001 define signal(2) as returning a pointer to a
function returning 'void'. K&R C signal(2) signature is obsolete.
Use 'void' directly.
Also, instead of writing the function pointer type explicitly, use
POSIX's 'sighandler_t'.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
nss_init() does not modify its path argument, thus declare it const.
Also drop superfluous prototype.
nss.c:54:31: warning: assignment discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
54 | nsswitch_path = NSSWITCH;
| ^
Function declarations with no argument declare functions taking an
arbitrary number of arguments. Use the special type void to declare
functions taking no argument.
C89 defined isdigit as a function that tests for any decimal-digit
character, defining the decimal digits as 0 1 2 3 4 5 6 7 8 9.
I don't own a copy of C89 to check, but check in C17:
7.4.1.5
5.2.1
More specifically:
> In both the source and execution basic character sets, the value
> of each character after 0 in the above list of decimal digits
> shall be one greater than the value of the previous.
And since in ascii(7), the character after '9' is ':', it's highly
unlikely that any implementation will ever accept any
_decimal digit_ other than 0..9.
POSIX simply defers to the ISO C standard.
This is exactly what we wanted from ISDIGIT(c), so just use it.
Non-standard implementations might have been slower or considered
other characters as digits in the past, but let's assume
implementations available today conform to ISO C89.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
It wasn't being used at all. Let's remove it.
Use isdigit(3) directly in comments that referenced it.
Also, in those comments, remove an outdated reference to the fact
that ISDIGIT_LOCALE(c) might evaluate its argument more than once,
which could be true a few commits ago, until
IN_CTYPE_DEFINITION(c) was removed. Previously, the definition
for ISDIGIT_LOCALE(c) was:
#if defined (STDC_HEADERS) || (!defined (isascii) && !defined (HAVE_ISASCII))
# define IN_CTYPE_DOMAIN(c) 1
#else
# define IN_CTYPE_DOMAIN(c) isascii(c)
#endif
#define ISDIGIT_LOCALE(c) (IN_CTYPE_DOMAIN (c) && isdigit (c))
Which could evaluate 'c' twice on pre-C89 systems (which I hope
don't exist nowadays).
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Due to the recent removal of IN_CTYPE_DOMAIN(), the uppercase
macros that wrapped these standard calls are now defined to be
equivalent. Therefore, there's no need for the wrappers, and it
is much more readable to use the standard calls directly.
However, hold on with ISDIGIT*(), since it's not so obvious what
to do with it.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
The recent removal of STDC_HEADERS made IN_CTYPE_DOMAIN be defined
to 1 unconditionally. Remove the now unnecessary definition, and
propagate its truthness to expressions where it was used.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
We're in 2021. C89 is everywhere; in fact, there are many other
assumptions in the code that wouldn't probably hold on
pre-standard C environments. Let's simplify and assume that C89
is available.
The specific assumptions are that:
- <string.h>, and <stdlib.h> are available
- strchr(3), strrchr(3), and strtok(3) are available
- isalpha(3), isspace(3), isdigit(3), and isupper(3) are available
I think we can safely assume we have all of those.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
memcpy(3) has been in standard C since C89. It is also in
POSIX.1-2001, in SVr4, and in 4.3BSD (see memcpy(3) and memcpy(3p)).
We can assume that this function is always available.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
strftime(3) has been in standard C since C89. It is also in
POSIX.1-2001, and in SVr4 (see strftime(3) and strftime(3p)).
We can assume that this function is always available.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
PARAMETERS:
According to the C2x charter, I reordered the parameters 'size'
and 'buf' from previously existing date_to_str() definitions.
C2x charter:
> 15. Application Programming Interfaces (APIs) should be
> self-documenting when possible. In particular, the order of
> parameters in function declarations should be arranged such that
> the size of an array appears before the array. The purpose is to
> allow Variable-Length Array (VLA) notation to be used. This not
> only makes the code's purpose clearer to human readers, but also
> makes static analysis easier. Any new APIs added to the Standard
> should take this into consideration.
I used 'long' for the date parameter, as some uses of the function
need to pass a negative value meaning "never".
FUNCTION BODY:
I didn't check '#ifdef HAVE_STRFTIME', which old definitions did,
since strftime(3) is guaranteed by the C89 standard, and all of
the conversion specifiers that we use are also specified by that
standard, so we don't need any extensions at all.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
When using groupdel with a prefix, groupdel will attempt to read a
passwd file to look for any user in the group. When the file does not
exist it cores with segmentation fault.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1986111
If a line in hushlogins file, e.g. /etc/hushlogins, starts with
'\0', then current code performs an out of boundary write.
If the line lacks a newline at the end, then another character is
overridden.
With strcspn both cases are solved.
Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
If SHA_CRYPT_MIN_ROUNDS and SHA_CRYPT_MAX_ROUNDS are both unspecified,
use SHA_ROUNDS_DEFAULT.
Previously, the code fell through, calling shadow_random(-1, -1). This
ultimately set rounds = (unsigned long) -1, which ends up being a very
large number! This then got capped to SHA_ROUNDS_MAX later in the
function.
The new behavior matches BCRYPT_get_salt_rounds().
Bug: https://bugs.gentoo.org/808195
Fixes: https://github.com/shadow-maint/shadow/issues/393
There's a better way to do this, and I hope to clean that up,
but this fixes out of tree builds for me right now.
Closes#386
Signed-off-by: Serge Hallyn <serge@hallyn.com>
In 9eb191edc4 I included a free() that
frees the members variable, which in turn causes the comma_to_list()
function to return an array of empty elements. The array variable holds
a list of pointers that point to offsets of the members variable. When
the function succeeds freeing members variable causes the elements of
the array variable to point to an empty string.
This is causing several regressions in our internal testing environment.
So, I'm reverting the change.
Signed-off-by: Iker Pedrosa <ipedrosa@redhat.com>
Most Linux distributions, including Fedora and RHEL 8, are shipping
with libxcrypt >= 4.0.
Since that version of libxcrypt the provided family of crypt_gensalt()
functions are able to use automatic entropy drawn from secure system
ressources, like arc4random(), getentropy() or getrandom().
Anyways, the settings generated by crypt_gensalt() are always
guaranteed to works with the crypt() function.
Using crypt_gensalt() is also needed to make proper use of newer
hashing methods, like yescrypt, provided by libxcrypt.
Signed-off-by: Björn Esser <besser82@fedoraproject.org>
In a previous commit we introduced /dev/urandom as a source to obtain
random bytes from. This may not be available on all systems, or when
operating inside of a chroot.
Almost all systems provide functions to obtain random bytes from
secure system ressources. Thus we should prefer to use these, and
fall back to /dev/urandom, if there is no such function present, as
a last resort.
Signed-off-by: Björn Esser <besser82@fedoraproject.org>
Error: RESOURCE_LEAK (CWE-772): [#def1]
shadow-4.8.1/lib/commonio.c:320: alloc_fn: Storage is returned from allocation function "fopen_set_perms".
shadow-4.8.1/lib/commonio.c:320: var_assign: Assigning: "bkfp" = storage returned from "fopen_set_perms(backup, "w", &sb)".
shadow-4.8.1/lib/commonio.c:329: noescape: Resource "bkfp" is not freed or pointed-to in "putc".
shadow-4.8.1/lib/commonio.c:334: noescape: Resource "bkfp" is not freed or pointed-to in "fflush".
shadow-4.8.1/lib/commonio.c:339: noescape: Resource "bkfp" is not freed or pointed-to in "fileno".
shadow-4.8.1/lib/commonio.c:342: leaked_storage: Variable "bkfp" going out of scope leaks the storage it points to.
340| || (fclose (bkfp) != 0)) {
341| /* FIXME: unlink the backup file? */
342|-> return -1;
343| }
344|
Error: RESOURCE_LEAK (CWE-772): [#def2]
shadow-4.8.1/libmisc/addgrps.c:69: alloc_fn: Storage is returned from allocation function "malloc".
shadow-4.8.1/libmisc/addgrps.c:69: var_assign: Assigning: "grouplist" = storage returned from "malloc(i * 4UL)".
shadow-4.8.1/libmisc/addgrps.c:73: noescape: Resource "grouplist" is not freed or pointed-to in "getgroups". [Note: The source code implementation of the function has been overridden by a builtin model.]
shadow-4.8.1/libmisc/addgrps.c:126: leaked_storage: Variable "grouplist" going out of scope leaks the storage it points to.
124| }
125|
126|-> return 0;
127| }
128| #else /* HAVE_SETGROUPS && !USE_PAM */
Error: RESOURCE_LEAK (CWE-772): [#def3]
shadow-4.8.1/libmisc/chowntty.c:62: alloc_fn: Storage is returned from allocation function "getgr_nam_gid".
shadow-4.8.1/libmisc/chowntty.c:62: var_assign: Assigning: "grent" = storage returned from "getgr_nam_gid(getdef_str("TTYGROUP"))".
shadow-4.8.1/libmisc/chowntty.c:98: leaked_storage: Variable "grent" going out of scope leaks the storage it points to.
96| */
97| #endif
98|-> }
99|
Error: RESOURCE_LEAK (CWE-772): [#def4]
shadow-4.8.1/libmisc/copydir.c:742: open_fn: Returning handle opened by "open". [Note: The source code implementation of the function has been overridden by a user model.]
shadow-4.8.1/libmisc/copydir.c:742: var_assign: Assigning: "ifd" = handle returned from "open(src, 0)".
shadow-4.8.1/libmisc/copydir.c:748: leaked_handle: Handle variable "ifd" going out of scope leaks the handle.
746| #ifdef WITH_SELINUX
747| if (set_selinux_file_context (dst, NULL) != 0) {
748|-> return -1;
749| }
750| #endif /* WITH_SELINUX */
Error: RESOURCE_LEAK (CWE-772): [#def5]
shadow-4.8.1/libmisc/copydir.c:751: open_fn: Returning handle opened by "open". [Note: The source code implementation of the function has been overridden by a user model.]
shadow-4.8.1/libmisc/copydir.c:751: var_assign: Assigning: "ofd" = handle returned from "open(dst, 577, statp->st_mode & 0xfffU)".
shadow-4.8.1/libmisc/copydir.c:752: noescape: Resource "ofd" is not freed or pointed-to in "fchown_if_needed".
shadow-4.8.1/libmisc/copydir.c:775: leaked_handle: Handle variable "ofd" going out of scope leaks the handle.
773| ) {
774| (void) close (ifd);
775|-> return -1;
776| }
777|
Error: RESOURCE_LEAK (CWE-772): [#def7]
shadow-4.8.1/libmisc/idmapping.c:188: alloc_fn: Storage is returned from allocation function "xmalloc".
shadow-4.8.1/libmisc/idmapping.c:188: var_assign: Assigning: "buf" = storage returned from "xmalloc(bufsize)".
shadow-4.8.1/libmisc/idmapping.c:188: var_assign: Assigning: "pos" = "buf".
shadow-4.8.1/libmisc/idmapping.c:213: noescape: Resource "buf" is not freed or pointed-to in "write".
shadow-4.8.1/libmisc/idmapping.c:219: leaked_storage: Variable "pos" going out of scope leaks the storage it points to.
shadow-4.8.1/libmisc/idmapping.c:219: leaked_storage: Variable "buf" going out of scope leaks the storage it points to.
217| }
218| close(fd);
219|-> }
Error: RESOURCE_LEAK (CWE-772): [#def8]
shadow-4.8.1/libmisc/list.c:211: alloc_fn: Storage is returned from allocation function "xstrdup".
shadow-4.8.1/libmisc/list.c:211: var_assign: Assigning: "members" = storage returned from "xstrdup(comma)".
shadow-4.8.1/libmisc/list.c:217: var_assign: Assigning: "cp" = "members".
shadow-4.8.1/libmisc/list.c:218: noescape: Resource "cp" is not freed or pointed-to in "strchr".
shadow-4.8.1/libmisc/list.c:244: leaked_storage: Variable "cp" going out of scope leaks the storage it points to.
shadow-4.8.1/libmisc/list.c:244: leaked_storage: Variable "members" going out of scope leaks the storage it points to.
242| if ('\0' == *members) {
243| *array = (char *) 0;
244|-> return array;
245| }
246|
Error: RESOURCE_LEAK (CWE-772): [#def11]
shadow-4.8.1/libmisc/myname.c:61: alloc_fn: Storage is returned from allocation function "xgetpwnam".
shadow-4.8.1/libmisc/myname.c:61: var_assign: Assigning: "pw" = storage returned from "xgetpwnam(cp)".
shadow-4.8.1/libmisc/myname.c:67: leaked_storage: Variable "pw" going out of scope leaks the storage it points to.
65| }
66|
67|-> return xgetpwuid (ruid);
68| }
69|
Error: RESOURCE_LEAK (CWE-772): [#def12]
shadow-4.8.1/libmisc/user_busy.c:260: alloc_fn: Storage is returned from allocation function "opendir".
shadow-4.8.1/libmisc/user_busy.c:260: var_assign: Assigning: "task_dir" = storage returned from "opendir(task_path)".
shadow-4.8.1/libmisc/user_busy.c:262: noescape: Resource "task_dir" is not freed or pointed-to in "readdir".
shadow-4.8.1/libmisc/user_busy.c:278: leaked_storage: Variable "task_dir" going out of scope leaks the storage it points to.
276| _("%s: user %s is currently used by process %d\n"),
277| Prog, name, pid);
278|-> return 1;
279| }
280| }
Error: RESOURCE_LEAK (CWE-772): [#def20]
shadow-4.8.1/src/newgrp.c:162: alloc_fn: Storage is returned from allocation function "xgetspnam".
shadow-4.8.1/src/newgrp.c:162: var_assign: Assigning: "spwd" = storage returned from "xgetspnam(pwd->pw_name)".
shadow-4.8.1/src/newgrp.c:234: leaked_storage: Variable "spwd" going out of scope leaks the storage it points to.
232| }
233|
234|-> return;
235|
236| failure:
Error: RESOURCE_LEAK (CWE-772): [#def21]
shadow-4.8.1/src/passwd.c:530: alloc_fn: Storage is returned from allocation function "xstrdup".
shadow-4.8.1/src/passwd.c:530: var_assign: Assigning: "cp" = storage returned from "xstrdup(crypt_passwd)".
shadow-4.8.1/src/passwd.c:551: noescape: Resource "cp" is not freed or pointed-to in "strlen".
shadow-4.8.1/src/passwd.c:554: noescape: Resource "cp" is not freed or pointed-to in "strcat". [Note: The source code implementation of the function has been overridden by a builtin model.]
shadow-4.8.1/src/passwd.c:555: overwrite_var: Overwriting "cp" in "cp = newpw" leaks the storage that "cp" points to.
553| strcpy (newpw, "!");
554| strcat (newpw, cp);
555|-> cp = newpw;
556| }
557| return cp;
Using the random() function to obtain pseudo-random bytes
for generating salt strings is considered to be dangerous.
See CWE-327.
We really should use a more reliable source for obtaining
pseudo-random bytes like /dev/urandom.
Fixes#376.
Signed-off-by: Björn Esser <besser82@fedoraproject.org>
In the previous commit we refactored the functions converting the
rounds number into a string for use with the crypt() function, to
not require any static buffer anymore.
Add some clarifying comments about how the minimum required buffer
length is computed inside of these functions.
Signed-off-by: Björn Esser <besser82@fedoraproject.org>
* Move all pre-processor defines to the top of the file.
* Unify the gensalt() function to be useable for all supported
hash methods.
* Drop the gensalt_{b,yes}crypt() functions in favor of the
previous change.
* Refactor the functions converting the rounds number into
a string for use with the crypt() function, to not require
any static buffer anymore.
* Clarify the comment about how crypt_make_salt() chooses the used
hash method from the settings in the login.defs file.
* Use memset() to fill static buffers with zero before using them.
* Use a fixed amount of 16 random base64-chars for the
sha{256,512}crypt hash methods, which is effectively still less
than the recommendation from NIST (>= 128 bits), but the maximum
those methods can effectively use (approx. 90 bits).
* Rename ROUNDS_{MIN,MAX} to SHA_ROUNDS_{MIN,MAX}.
* Bugfixes in the logic of setting rounds in BCRYPT_salt_rounds().
* Likewise for YESCRYPT_salt_cost().
* Fix formatting and white-space errors.
Signed-off-by: Björn Esser <besser82@fedoraproject.org>
The corresponding functions for the other hash methods all take
a pointer to an integer value as the only paramater, so this
particular function should do so as well.
Signed-off-by: Björn Esser <besser82@fedoraproject.org>
Closes#325
Add a new subid_init() function which can be used to specify the
stream on which error messages should be printed. (If you want to
get fancy you can redirect that to memory :) If subid_init() is
not called, use stderr. If NULL is passed, then /dev/null will
be used.
This patch also fixes up the 'Prog', which previously had to be
defined by any program linking against libsubid. Now, by default
in libsubid it will show (subid). Once subid_init() is called,
it will use the first variable passed to subid_init().
Signed-off-by: Serge Hallyn <serge@hallyn.com>
When uid 0 maps host uid 0 into the child userns newer kernels require
CAP_SETFCAP be retained as this allows the caller to create fscaps that
are valid in the ancestor userns. This was a security issue (in very
rare circumstances). So whenever host uid 0 is mapped, retain
CAP_SETFCAP if the caller had it.
Userspace won't need to set CAP_SETFCAP on newuidmap as this is really
only a scenario that real root should be doing which always has
CAP_SETFCAP. And if they don't then they are in a locked-down userns.
(LXC sometimes maps host uid 0 during chown operations in a helper
userns but will not rely on newuidmap for that. But we don't want to
risk regressing callers that want to rely on this behavior.)
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
