/[imapfilter]/imapfilter/memory.c
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Annotation of /imapfilter/memory.c

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Revision 1.21 - (hide annotations)
Fri Feb 13 23:44:50 2004 UTC (20 years, 1 month ago) by lefcha
Branch: MAIN
Changes since 1.20: +2 -2 lines
File MIME type: text/plain
Rephrasing.

1 lefcha 1.1 #include <stdlib.h>
2 lefcha 1.17 #include <stdlib.h>
3     #include <unistd.h>
4 lefcha 1.16 #include <string.h>
5 lefcha 1.1 #include <errno.h>
6 lefcha 1.21 #include <sys/types.h> /* For POSIX.1-2001 non-conformant systems. */
7     #include <sys/time.h> /* For POSIX.1-2001 non-conformant systems. */
8 lefcha 1.6 #include <sys/resource.h>
9    
10 lefcha 1.12 #include "config.h"
11 lefcha 1.1 #include "imapfilter.h"
12    
13 lefcha 1.4
14 lefcha 1.16 /* Secure memory information. */
15     typedef struct secmem {
16     void *buf; /* Allocated memory buffer. */
17     size_t size; /* Size of the buffer. */
18     struct secmem *prev, *next; /* Previous/next node of doubly linked
19     * list. */
20     } secmem_t;
21    
22    
23 lefcha 1.11 extern unsigned int options;
24 lefcha 1.13
25 lefcha 1.19 static secmem_t *secmem = NULL; /* First node of secure memory linked list. */
26 lefcha 1.16
27    
28 lefcha 1.19 void secmem_append(secmem_t * sm);
29 lefcha 1.16 secmem_t *secmem_find(void *ptr);
30 lefcha 1.19 void secmem_remove(secmem_t * sm);
31 lefcha 1.7
32 lefcha 1.6
33 lefcha 1.1 /*
34 lefcha 1.3 * A malloc() that checks the results and dies in case of error.
35 lefcha 1.1 */
36 lefcha 1.13 void *
37     xmalloc(size_t size)
38 lefcha 1.1 {
39 lefcha 1.13 void *ptr;
40 lefcha 1.2
41 lefcha 1.13 ptr = (void *)malloc(size);
42 lefcha 1.2
43 lefcha 1.13 if (ptr == NULL)
44 lefcha 1.19 fatal(ERROR_MEMALLOC,
45 lefcha 1.13 "allocating memory; %s\n", strerror(errno));
46 lefcha 1.2
47 lefcha 1.13 return ptr;
48 lefcha 1.1 }
49    
50    
51     /*
52 lefcha 1.3 * A realloc() that checks the results and dies in case of error.
53     */
54 lefcha 1.13 void *
55     xrealloc(void *ptr, size_t size)
56 lefcha 1.3 {
57 lefcha 1.13 ptr = (void *)realloc(ptr, size);
58 lefcha 1.3
59 lefcha 1.13 if (ptr == NULL)
60 lefcha 1.19 fatal(ERROR_MEMALLOC,
61 lefcha 1.13 "allocating memory; %s\n", strerror(errno));
62 lefcha 1.3
63 lefcha 1.13 return ptr;
64 lefcha 1.3 }
65    
66    
67     /*
68 lefcha 1.5 * A free() that dies if fed with NULL pointer.
69     */
70 lefcha 1.13 void
71     xfree(void *ptr)
72 lefcha 1.5 {
73 lefcha 1.20
74 lefcha 1.13 if (ptr == NULL)
75 lefcha 1.19 fatal(ERROR_MEMALLOC,
76 lefcha 1.13 "NULL pointer given as argument");
77     free(ptr);
78 lefcha 1.5 }
79    
80    
81     /*
82 lefcha 1.3 * A strdup() that checks the results and dies in case of error.
83 lefcha 1.1 */
84 lefcha 1.13 char *
85     xstrdup(const char *s)
86 lefcha 1.1 {
87 lefcha 1.13 char *cp;
88 lefcha 1.2
89 lefcha 1.13 cp = strdup(s);
90 lefcha 1.2
91 lefcha 1.13 if (cp == NULL)
92 lefcha 1.19 fatal(ERROR_MEMALLOC, "allocating memory; %s\n", strerror(errno));
93 lefcha 1.2
94 lefcha 1.13 return cp;
95 lefcha 1.6 }
96    
97    
98     /*
99     * Secure memory malloc(). Locks memory and keeps information about the
100     * chunk that was allocated.
101     */
102 lefcha 1.13 void *
103     smalloc(size_t size)
104 lefcha 1.6 {
105 lefcha 1.13 void *ptr;
106 lefcha 1.19 secmem_t *sm;
107 lefcha 1.10
108 lefcha 1.13 ptr = xmalloc(size);
109 lefcha 1.10
110 lefcha 1.19 sm = (secmem_t *) xmalloc(sizeof(secmem_t));
111 lefcha 1.10
112 lefcha 1.19 sm->buf = ptr;
113     sm->size = size;
114     sm->prev = sm->next = NULL;
115 lefcha 1.10
116 lefcha 1.19 secmem_append(sm);
117 lefcha 1.10
118 lefcha 1.13 return ptr;
119 lefcha 1.6 }
120    
121    
122     /*
123     * Secure memory realloc(). Resize memory by allocating a new memory chunk
124     * and NULL fill old memory, in order to protect sensitive data.
125     */
126 lefcha 1.13 void *
127     srealloc(void *ptr, size_t size)
128 lefcha 1.6 {
129 lefcha 1.13 void *p;
130 lefcha 1.19 secmem_t *sm;
131 lefcha 1.10
132 lefcha 1.19 if (!(sm = (secmem_t *) secmem_find(ptr))) {
133 lefcha 1.13 ptr = xrealloc(ptr, size);
134     return ptr;
135     }
136     p = smalloc(size);
137 lefcha 1.19 memcpy(p, sm->buf, min(sm->size, size));
138 lefcha 1.13
139 lefcha 1.19 memset(sm->buf, 0, sm->size);
140     secmem_remove(sm);
141     xfree(sm->buf);
142     xfree(sm);
143 lefcha 1.10
144 lefcha 1.13 return p;
145 lefcha 1.6 }
146    
147    
148     /*
149     * Secure memory free(). NULL fill memory before freeing it.
150     */
151 lefcha 1.13 void
152     sfree(void *ptr)
153 lefcha 1.6 {
154 lefcha 1.19 secmem_t *sm;
155 lefcha 1.10
156 lefcha 1.19 if (!(sm = (secmem_t *) secmem_find(ptr))) {
157 lefcha 1.13 xfree(ptr);
158     return;
159     }
160 lefcha 1.19 memset(sm->buf, 0, sm->size);
161     secmem_remove(sm);
162     xfree(sm->buf);
163     xfree(sm);
164 lefcha 1.6 }
165    
166    
167     /*
168 lefcha 1.9 * Secure memory strdup(). Uses secure memory allocation.
169 lefcha 1.6 */
170 lefcha 1.13 char *
171     sstrdup(const char *s)
172 lefcha 1.6 {
173 lefcha 1.13 char *p;
174 lefcha 1.10
175 lefcha 1.13 p = (char *)smalloc(strlen(s) + 1);
176     xstrncpy(p, s, strlen(s));
177 lefcha 1.10
178 lefcha 1.13 return p;
179 lefcha 1.6 }
180    
181    
182     /*
183     * Append information about the newly allocated memory buffer.
184     */
185 lefcha 1.13 void
186 lefcha 1.19 secmem_append(secmem_t * sm)
187 lefcha 1.6 {
188 lefcha 1.13 secmem_t *pos;
189     secmem_t **app;
190 lefcha 1.10
191 lefcha 1.19 app = &secmem;
192     pos = secmem;
193 lefcha 1.6
194 lefcha 1.13 while (pos) {
195 lefcha 1.19 sm->prev = pos;
196 lefcha 1.13 app = &(pos->next);
197     pos = pos->next;
198     }
199 lefcha 1.10
200 lefcha 1.19 *app = sm;
201 lefcha 1.6 }
202    
203    
204     /*
205     * Find the record of a memory buffer in the secure memory linked list.
206     */
207 lefcha 1.13 secmem_t *
208     secmem_find(void *ptr)
209 lefcha 1.6 {
210 lefcha 1.13 secmem_t *pos;
211 lefcha 1.10
212 lefcha 1.19 pos = secmem;
213 lefcha 1.10
214 lefcha 1.13 while (pos != NULL && pos->buf != ptr)
215     pos = pos->next;
216 lefcha 1.10
217 lefcha 1.13 return pos;
218 lefcha 1.6 }
219 lefcha 1.10
220 lefcha 1.6
221     /*
222     * Remove a record of a secure memory buffer.
223     */
224 lefcha 1.13 void
225 lefcha 1.19 secmem_remove(secmem_t * sm)
226 lefcha 1.6 {
227 lefcha 1.20
228 lefcha 1.19 if (sm->prev != NULL)
229     sm->prev->next = sm->next;
230     if (sm->next != NULL)
231     sm->next->prev = sm->prev;
232     if (secmem == sm)
233     secmem = sm->next;
234 lefcha 1.14
235 lefcha 1.6 }
236    
237    
238     /*
239     * Overwrite/clear all secure memory.
240     */
241 lefcha 1.13 void
242     secmem_clear(void)
243 lefcha 1.6 {
244 lefcha 1.14 secmem_t *p, *t;
245 lefcha 1.10
246 lefcha 1.19 for (p = secmem; p != NULL; p = t) {
247 lefcha 1.14 t = p->next;
248     sfree(p->buf);
249     }
250 lefcha 1.6 }
251 lefcha 1.8
252    
253     /*
254 lefcha 1.9 * Disable core file dumping.
255 lefcha 1.6 */
256 lefcha 1.13 void
257     corefile_disable(void)
258 lefcha 1.6 {
259 lefcha 1.13 struct rlimit rl;
260 lefcha 1.7
261 lefcha 1.13 getrlimit(RLIMIT_CORE, &rl);
262 lefcha 1.10
263 lefcha 1.13 rl.rlim_cur = rl.rlim_max = 0;
264     setrlimit(RLIMIT_CORE, &rl);
265 lefcha 1.2 }

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