| Reilly Grant | d883f52 | 2016-02-21 18:38:01 -0300 | [diff] [blame] | 1 | #include <sys/ioctl.h> |
| 2 | #include <sys/types.h> |
| 3 | #include <sys/stat.h> |
| 4 | #include <fcntl.h> |
| 5 | #include <stdio.h> |
| 6 | #include <errno.h> |
| 7 | #include <string.h> |
| 8 | #include <inttypes.h> |
| 9 | #include <unistd.h> |
| 10 | |
| 11 | #include <linux/usbdevice_fs.h> |
| 12 | |
| 13 | /* For building without an updated set of headers */ |
| 14 | #ifndef USBDEVFS_DROP_PRIVILEGES |
| 15 | #define USBDEVFS_DROP_PRIVILEGES _IOW('U', 30, __u32) |
| 16 | #define USBDEVFS_CAP_DROP_PRIVILEGES 0x40 |
| 17 | #endif |
| 18 | |
| 19 | void drop_privileges(int fd, uint32_t mask) |
| 20 | { |
| 21 | int res; |
| 22 | |
| 23 | res = ioctl(fd, USBDEVFS_DROP_PRIVILEGES, &mask); |
| 24 | if (res) |
| 25 | printf("ERROR: USBDEVFS_DROP_PRIVILEGES returned %d\n", res); |
| 26 | else |
| 27 | printf("OK: privileges dropped!\n"); |
| 28 | } |
| 29 | |
| 30 | void reset_device(int fd) |
| 31 | { |
| 32 | int res; |
| 33 | |
| 34 | res = ioctl(fd, USBDEVFS_RESET); |
| 35 | if (!res) |
| 36 | printf("OK: USBDEVFS_RESET succeeded\n"); |
| 37 | else |
| 38 | printf("ERROR: reset failed! (%d - %s)\n", |
| 39 | -res, strerror(-res)); |
| 40 | } |
| 41 | |
| 42 | void claim_some_intf(int fd) |
| 43 | { |
| 44 | int i, res; |
| 45 | |
| 46 | for (i = 0; i < 4; i++) { |
| 47 | res = ioctl(fd, USBDEVFS_CLAIMINTERFACE, &i); |
| 48 | if (!res) |
| 49 | printf("OK: claimed if %d\n", i); |
| 50 | else |
| 51 | printf("ERROR claiming if %d (%d - %s)\n", |
| 52 | i, -res, strerror(-res)); |
| 53 | } |
| 54 | } |
| 55 | |
| 56 | int main(int argc, char *argv[]) |
| 57 | { |
| 58 | uint32_t mask, caps; |
| 59 | int c, fd; |
| 60 | |
| 61 | fd = open(argv[1], O_RDWR); |
| 62 | if (fd < 0) { |
| 63 | printf("Failed to open file\n"); |
| 64 | goto err_fd; |
| 65 | } |
| 66 | |
| 67 | /* |
| 68 | * check if dropping privileges is supported, |
| 69 | * bail on systems where the capability is not present |
| 70 | */ |
| 71 | ioctl(fd, USBDEVFS_GET_CAPABILITIES, &caps); |
| 72 | if (!(caps & USBDEVFS_CAP_DROP_PRIVILEGES)) { |
| 73 | printf("DROP_PRIVILEGES not supported\n"); |
| 74 | goto err; |
| 75 | } |
| 76 | |
| 77 | /* |
| 78 | * Drop privileges but keep the ability to claim all |
| 79 | * free interfaces (i.e., those not used by kernel drivers) |
| 80 | */ |
| 81 | drop_privileges(fd, -1U); |
| 82 | |
| 83 | printf("Available options:\n" |
| 84 | "[0] Exit now\n" |
| 85 | "[1] Reset device. Should fail if device is in use\n" |
| 86 | "[2] Claim 4 interfaces. Should succeed where not in use\n" |
| 87 | "[3] Narrow interface permission mask\n" |
| 88 | "Which option shall I run?: "); |
| 89 | |
| 90 | while (scanf("%d", &c) == 1) { |
| 91 | switch (c) { |
| 92 | case 0: |
| 93 | goto exit; |
| 94 | case 1: |
| 95 | reset_device(fd); |
| 96 | break; |
| 97 | case 2: |
| 98 | claim_some_intf(fd); |
| 99 | break; |
| 100 | case 3: |
| 101 | printf("Insert new mask: "); |
| 102 | scanf("%x", &mask); |
| 103 | drop_privileges(fd, mask); |
| 104 | break; |
| 105 | default: |
| 106 | printf("I don't recognize that\n"); |
| 107 | } |
| 108 | |
| 109 | printf("Which test shall I run next?: "); |
| 110 | } |
| 111 | |
| 112 | exit: |
| 113 | close(fd); |
| 114 | return 0; |
| 115 | |
| 116 | err: |
| 117 | close(fd); |
| 118 | err_fd: |
| 119 | return 1; |
| 120 | } |