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Diffstat (limited to 'src/passwd/getspnam_r.c')
-rw-r--r--src/passwd/getspnam_r.c89
1 files changed, 89 insertions, 0 deletions
diff --git a/src/passwd/getspnam_r.c b/src/passwd/getspnam_r.c
new file mode 100644
index 00000000..1dd39ce0
--- /dev/null
+++ b/src/passwd/getspnam_r.c
@@ -0,0 +1,89 @@
+#include <fcntl.h>
+#include <unistd.h>
+#include "pwf.h"
+
+/* This implementation support Openwall-style TCB passwords in place of
+ * traditional shadow, if the appropriate directories and files exist.
+ * Thus, it is careful to avoid following symlinks or blocking on fifos
+ * which a malicious user might create in place of his or her TCB shadow
+ * file. It also avoids any allocation to prevent memory-exhaustion
+ * attacks via huge TCB shadow files. */
+
+int getspnam_r(const char *name, struct spwd *sp, char *buf, size_t size, struct spwd **res)
+{
+ char path[20+NAME_MAX];
+ FILE *f = 0;
+ int rv = 0;
+ int fd;
+ size_t k, l = strlen(name);
+ char *s;
+ int skip = 0;
+
+ *res = 0;
+
+ /* Disallow potentially-malicious user names */
+ if (*name=='.' || strchr(name, '/') || !l)
+ return EINVAL;
+
+ /* Buffer size must at least be able to hold name, plus some.. */
+ if (size < l+100) return ERANGE;
+
+ /* Protect against truncation */
+ if (snprintf(path, sizeof path, "/etc/tcb/%s/shadow", name) >= sizeof path)
+ return EINVAL;
+
+ fd = open(path, O_RDONLY|O_NOFOLLOW|O_NONBLOCK);
+ if (fd >= 0) {
+ f = fdopen(fd, "rb");
+ if (!f) {
+ close(fd);
+ return errno;
+ }
+ } else {
+ f = fopen("/etc/shadow", "rb");
+ if (!f) return errno;
+ }
+
+ while (fgets(buf, size, f) && (k=strlen(buf))>0) {
+ if (skip || strncmp(name, buf, l)) {
+ skip = buf[k-1] != '\n';
+ continue;
+ }
+ if (buf[k-1] != '\n') {
+ rv = ERANGE;
+ break;
+ }
+ buf[k-1] = 0;
+
+ s = buf;
+ sp->sp_namp = s;
+ if (!(s = strchr(s, ':'))) continue;
+
+ *s++ = 0; sp->sp_pwdp = s;
+ if (!(s = strchr(s, ':'))) continue;
+
+ *s++ = 0; sp->sp_lstchg = atol(s);
+ if (!(s = strchr(s, ':'))) continue;
+
+ *s++ = 0; sp->sp_min = atol(s);
+ if (!(s = strchr(s, ':'))) continue;
+
+ *s++ = 0; sp->sp_max = atol(s);
+ if (!(s = strchr(s, ':'))) continue;
+
+ *s++ = 0; sp->sp_warn = atol(s);
+ if (!(s = strchr(s, ':'))) continue;
+
+ *s++ = 0; sp->sp_inact = atol(s);
+ if (!(s = strchr(s, ':'))) continue;
+
+ *s++ = 0; sp->sp_expire = atol(s);
+ if (!(s = strchr(s, ':'))) continue;
+
+ *s++ = 0; sp->sp_flag = atol(s);
+ *res = sp;
+ break;
+ }
+ fclose(f);
+ return rv;
+}