| author | Christian Urban <christian dot urban at kcl dot ac dot uk> |
| Tue, 30 Dec 2014 01:22:25 +0000 | |
| changeset 364 | e4a879d442d5 |
| parent 360 | eb2004430215 |
| child 365 | 942205605c30 |
| permissions | -rw-r--r-- |
|
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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#include <stdio.h> |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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#include <stdlib.h> |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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#include <unistd.h> |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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#include <errno.h> |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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int main(int argc, char *argv[]) |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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{
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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FILE *f; //file pointer |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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printf("Real UID = %d\n", getuid());
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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printf("Effective UID = %d\n", geteuid());
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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//read test (error 13 is permission denied) |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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if ((f = fopen(argv[1], "r")) == NULL) {
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parents:
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fprintf(stderr, "%s is not readable, errno = %d\n", argv[1], errno); |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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} else {
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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fprintf(stderr, "%s is readable\n", argv[1]); fclose(f); |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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} |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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//write test |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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if ((f = fopen(argv[1], "r+")) == NULL) {
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parents:
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fprintf(stderr, "%s is not writable, errno = %d\n", argv[1], errno); |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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} else {
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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fprintf(stderr, "%s is writable\n", argv[1]); fclose(f); |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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} |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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//lowering the access rights to the caller |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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if (setuid(getuid())) {
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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fprintf(stderr, "could not reset setuid, errno = %d\n", errno); return 1; |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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} |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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printf("Real UID = %d\n", getuid());
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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printf("Effective UID = %d\n", geteuid());
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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//read test |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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if ((f = fopen(argv[1], "r")) == NULL) {
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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fprintf(stderr, "%s is not readable, errno = %d\n", argv[1], errno); |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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} else {
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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fprintf(stderr, "%s is readable\n", argv[1]); fclose(f); |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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} |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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//write test |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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if ((f = fopen(argv[1], "w")) == NULL) {
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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fprintf(stderr, "%s is not writable, errno = %d\n", argv[1], errno); |
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360
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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} else {
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eb2004430215
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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fprintf(stderr, "%s is writable\n", argv[1]); fclose(f); |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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} |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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return 0; |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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} |