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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 14:54:37 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 14:54:37 +0000 |
commit | 97c26c1924b076ef23ebe4381558e8aa025712b2 (patch) | |
tree | 109724175f07436696f51b14b5abbd3f4d704d6d /libmisc/xgetXXbyYY.c | |
parent | Initial commit. (diff) | |
download | shadow-e5df02f9b4d325b0ac1812e1456ba966566da242.tar.xz shadow-e5df02f9b4d325b0ac1812e1456ba966566da242.zip |
Adding upstream version 1:4.13+dfsg1.upstream/1%4.13+dfsg1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'libmisc/xgetXXbyYY.c')
-rw-r--r-- | libmisc/xgetXXbyYY.c | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/libmisc/xgetXXbyYY.c b/libmisc/xgetXXbyYY.c new file mode 100644 index 0000000..6a3f969 --- /dev/null +++ b/libmisc/xgetXXbyYY.c @@ -0,0 +1,121 @@ +/* + * SPDX-FileCopyrightText: 2007 - 2009, Nicolas François + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +/* + * According to the Linux-PAM documentation: + * + * 4.1. Care about standard library calls + * + * In general, writers of authorization-granting applications should + * assume that each module is likely to call any or all 'libc' functions. + * For 'libc' functions that return pointers to static/dynamically + * allocated structures (ie. the library allocates the memory and the + * user is not expected to 'free()' it) any module call to this function + * is likely to corrupt a pointer previously obtained by the application. + * The application programmer should either re-call such a 'libc' + * function after a call to the Linux-PAM library, or copy the structure + * contents to some safe area of memory before passing control to the + * Linux-PAM library. + * + * Two important function classes that fall into this category are + * getpwnam(3) and syslog(3). + * + * This file provide wrapper to the getpwnam or getpwnam_r functions. + */ + +#include <unistd.h> +#include <stdlib.h> +#include <stdio.h> +#include <errno.h> +#include "prototypes.h" +#include "shadowlog.h" + +#define XFUNCTION_NAME XPREFIX (FUNCTION_NAME) +#define XPREFIX(name) XPREFIX1 (name) +#define XPREFIX1(name) x##name +#define REENTRANT_NAME APPEND_R (FUNCTION_NAME) +#define APPEND_R(name) APPEND_R1 (name) +#define APPEND_R1(name) name##_r +#define STRINGIZE(name) STRINGIZE1 (name) +#define STRINGIZE1(name) #name + +/*@null@*/ /*@only@*/LOOKUP_TYPE *XFUNCTION_NAME (ARG_TYPE ARG_NAME) +{ +#if HAVE_FUNCTION_R + LOOKUP_TYPE *result=NULL; + char *buffer=NULL; + /* we have to start with something */ + size_t length = 0x100; + + result = malloc(sizeof(LOOKUP_TYPE)); + if (NULL == result) { + fprintf (log_get_logfd(), _("%s: out of memory\n"), + "x" STRINGIZE(FUNCTION_NAME)); + exit (13); + } + + while (true) { + int status; + LOOKUP_TYPE *resbuf = NULL; + buffer = (char *)realloc (buffer, length); + if (NULL == buffer) { + fprintf (log_get_logfd(), _("%s: out of memory\n"), + "x" STRINGIZE(FUNCTION_NAME)); + exit (13); + } + status = REENTRANT_NAME(ARG_NAME, result, buffer, + length, &resbuf); + if ((0 == status) && (resbuf == result)) { + /* Build a result structure that can be freed by + * the shadow *_free functions. */ + LOOKUP_TYPE *ret_result = DUP_FUNCTION(result); + free(buffer); + free(result); + return ret_result; + } + + if (ERANGE != status) { + free (buffer); + free (result); + return NULL; + } + + if (length <= ((size_t)-1 / 4)) { + length *= 4; + } else if (length == (size_t) -1) { + break; + } else { + length = (size_t) -1; + } + } + + free(buffer); + free(result); + return NULL; + +#else /* !HAVE_FUNCTION_R */ + + /* No reentrant function. + * Duplicate the structure to avoid other call to overwrite it. + * + * We should also restore the initial structure. But that would be + * overkill. + */ + LOOKUP_TYPE *result = FUNCTION_NAME(ARG_NAME); + + if (result) { + result = DUP_FUNCTION(result); + if (NULL == result) { + fprintf (log_get_logfd(), _("%s: out of memory\n"), + "x" STRINGIZE(FUNCTION_NAME)); + exit (13); + } + } + + return result; +#endif +} + |