Greater leniency when importing private key files: accept both CRLF

and LF, and don't object if the final line of the key lacks a
newline. Also, while I'm here, switch to using fgetline() throughout
so as not to have to do nasty buffer-size ad-hockery.

git-svn-id: svn://svn.tartarus.org/sgt/putty@7072 cda61777-01e9-0310-a592-d414129be87e

diff --git a/import.c b/import.c
index 6c936ff..7deb02f 100644 (file)
--- a/import.c
+++ b/import.c
@@ -109,6 +109,17 @@ int export_ssh2(const Filename *filename, int type,
     return 0;
 }
 
+/*
+ * Strip trailing CRs and LFs at the end of a line of text.
+ */
+void strip_crlf(char *str)
+{
+    char *p = str + strlen(str);
+
+    while (p > str && (p[-1] == '\r' || p[-1] == '\n'))
+       *--p = '\0';
+}
+
 /* ----------------------------------------------------------------------
  * Helper routines. (The base64 ones are defined in sshpubk.c.)
  */
@@ -310,7 +321,7 @@ static struct openssh_key *load_openssh_key(const Filename *filename,
 {
     struct openssh_key *ret;
     FILE *fp;
-    char buffer[256];
+    char *line = NULL;
     char *errmsg, *p;
     int headers_done;
     char base64_bit[4];
@@ -327,46 +338,55 @@ static struct openssh_key *load_openssh_key(const Filename *filename,
        errmsg = "unable to open key file";
        goto error;
     }
-    if (!fgets(buffer, sizeof(buffer), fp) ||
-       0 != strncmp(buffer, "-----BEGIN ", 11) ||
-       0 != strcmp(buffer+strlen(buffer)-17, "PRIVATE KEY-----\n")) {
+
+    if (!(line = fgetline(fp))) {
+       errmsg = "unexpected end of file";
+       goto error;
+    }
+    strip_crlf(line);
+    if (0 != strncmp(line, "-----BEGIN ", 11) ||
+       0 != strcmp(line+strlen(line)-16, "PRIVATE KEY-----")) {
        errmsg = "file does not begin with OpenSSH key header";
        goto error;
     }
-    if (!strcmp(buffer, "-----BEGIN RSA PRIVATE KEY-----\n"))
+    if (!strcmp(line, "-----BEGIN RSA PRIVATE KEY-----"))
        ret->type = OSSH_RSA;
-    else if (!strcmp(buffer, "-----BEGIN DSA PRIVATE KEY-----\n"))
+    else if (!strcmp(line, "-----BEGIN DSA PRIVATE KEY-----"))
        ret->type = OSSH_DSA;
     else {
        errmsg = "unrecognised key type";
        goto error;
     }
+    memset(line, 0, strlen(line));
+    sfree(line);
+    line = NULL;
 
     headers_done = 0;
     while (1) {
-       if (!fgets(buffer, sizeof(buffer), fp)) {
+       if (!(line = fgetline(fp))) {
            errmsg = "unexpected end of file";
            goto error;
        }
-       if (0 == strncmp(buffer, "-----END ", 9) &&
-           0 == strcmp(buffer+strlen(buffer)-17, "PRIVATE KEY-----\n"))
+       strip_crlf(line);
+       if (0 == strncmp(line, "-----END ", 9) &&
+           0 == strcmp(line+strlen(line)-16, "PRIVATE KEY-----"))
            break;                     /* done */
-       if ((p = strchr(buffer, ':')) != NULL) {
+       if ((p = strchr(line, ':')) != NULL) {
            if (headers_done) {
                errmsg = "header found in body of key data";
                goto error;
            }
            *p++ = '\0';
            while (*p && isspace((unsigned char)*p)) p++;
-           if (!strcmp(buffer, "Proc-Type")) {
+           if (!strcmp(line, "Proc-Type")) {
                if (p[0] != '4' || p[1] != ',') {
                    errmsg = "Proc-Type is not 4 (only 4 is supported)";
                    goto error;
                }
                p += 2;
-               if (!strcmp(p, "ENCRYPTED\n"))
+               if (!strcmp(p, "ENCRYPTED"))
                    ret->encrypted = 1;
-           } else if (!strcmp(buffer, "DEK-Info")) {
+           } else if (!strcmp(line, "DEK-Info")) {
                int i, j;
 
                if (strncmp(p, "DES-EDE3-CBC,", 13)) {
@@ -388,7 +408,7 @@ static struct openssh_key *load_openssh_key(const Filename *filename,
        } else {
            headers_done = 1;
 
-           p = buffer;
+           p = line;
            while (isbase64(*p)) {
                 base64_bit[base64_chars++] = *p;
                 if (base64_chars == 4) {
@@ -419,6 +439,9 @@ static struct openssh_key *load_openssh_key(const Filename *filename,
                p++;
            }
        }
+       memset(line, 0, strlen(line));
+       sfree(line);
+       line = NULL;
     }
 
     if (ret->keyblob_len == 0 || !ret->keyblob) {
@@ -431,13 +454,16 @@ static struct openssh_key *load_openssh_key(const Filename *filename,
        goto error;
     }
 
-    memset(buffer, 0, sizeof(buffer));
     memset(base64_bit, 0, sizeof(base64_bit));
     if (errmsg_p) *errmsg_p = NULL;
     return ret;
 
     error:
-    memset(buffer, 0, sizeof(buffer));
+    if (line) {
+       memset(line, 0, strlen(line));
+       sfree(line);
+       line = NULL;
+    }
     memset(base64_bit, 0, sizeof(base64_bit));
     if (ret) {
        if (ret->keyblob) {
@@ -989,8 +1015,8 @@ static struct sshcom_key *load_sshcom_key(const Filename *filename,
 {
     struct sshcom_key *ret;
     FILE *fp;
-    char buffer[256];
-    int len;
+    char *line = NULL;
+    int hdrstart, len;
     char *errmsg, *p;
     int headers_done;
     char base64_bit[4];
@@ -1006,44 +1032,67 @@ static struct sshcom_key *load_sshcom_key(const Filename *filename,
        errmsg = "unable to open key file";
        goto error;
     }
-    if (!fgets(buffer, sizeof(buffer), fp) ||
-       0 != strcmp(buffer, "---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----\n")) {
+    if (!(line = fgetline(fp))) {
+       errmsg = "unexpected end of file";
+       goto error;
+    }
+    strip_crlf(line);
+    if (0 != strcmp(line, "---- BEGIN SSH2 ENCRYPTED PRIVATE KEY ----")) {
        errmsg = "file does not begin with ssh.com key header";
        goto error;
     }
+    memset(line, 0, strlen(line));
+    sfree(line);
+    line = NULL;
 
     headers_done = 0;
     while (1) {
-       if (!fgets(buffer, sizeof(buffer), fp)) {
+       if (!(line = fgetline(fp))) {
            errmsg = "unexpected end of file";
            goto error;
        }
-        if (!strcmp(buffer, "---- END SSH2 ENCRYPTED PRIVATE KEY ----\n"))
+       strip_crlf(line);
+        if (!strcmp(line, "---- END SSH2 ENCRYPTED PRIVATE KEY ----"))
             break;                     /* done */
-       if ((p = strchr(buffer, ':')) != NULL) {
+       if ((p = strchr(line, ':')) != NULL) {
            if (headers_done) {
                errmsg = "header found in body of key data";
                goto error;
            }
            *p++ = '\0';
            while (*p && isspace((unsigned char)*p)) p++;
+           hdrstart = p - line;
+
             /*
              * Header lines can end in a trailing backslash for
              * continuation.
              */
-            while ((len = strlen(p)) > (int)(sizeof(buffer) - (p-buffer) -1) ||
-                   p[len-1] != '\n' || p[len-2] == '\\') {
-                if (len > (int)((p-buffer) + sizeof(buffer)-2)) {
-                    errmsg = "header line too long to deal with";
-                    goto error;
-                }
-                if (!fgets(p+len-2, sizeof(buffer)-(p-buffer)-(len-2), fp)) {
+           len = hdrstart + strlen(line+hdrstart);
+           assert(!line[len]);
+            while (line[len-1] == '\\') {
+               char *line2;
+               int line2len;
+
+               line2 = fgetline(fp);
+               if (!line2) {
                     errmsg = "unexpected end of file";
                     goto error;
                 }
+               strip_crlf(line2);
+
+               line2len = strlen(line2);
+               line = sresize(line, len + line2len + 1, char);
+               strcpy(line + len - 1, line2);
+               len += line2len - 1;
+               assert(!line[len]);
+
+               memset(line2, 0, strlen(line2));
+               sfree(line2);
+               line2 = NULL;
             }
-            p[strcspn(p, "\n")] = '\0';
-            if (!strcmp(buffer, "Comment")) {
+           p = line + hdrstart;
+           strip_crlf(p);
+            if (!strcmp(line, "Comment")) {
                 /* Strip quotes in comment if present. */
                 if (p[0] == '"' && p[strlen(p)-1] == '"') {
                     p++;
@@ -1055,7 +1104,7 @@ static struct sshcom_key *load_sshcom_key(const Filename *filename,
        } else {
            headers_done = 1;
 
-           p = buffer;
+           p = line;
            while (isbase64(*p)) {
                 base64_bit[base64_chars++] = *p;
                 if (base64_chars == 4) {
@@ -1083,6 +1132,9 @@ static struct sshcom_key *load_sshcom_key(const Filename *filename,
                p++;
            }
        }
+       memset(line, 0, strlen(line));
+       sfree(line);
+       line = NULL;
     }
 
     if (ret->keyblob_len == 0 || !ret->keyblob) {
@@ -1094,6 +1146,11 @@ static struct sshcom_key *load_sshcom_key(const Filename *filename,
     return ret;
 
     error:
+    if (line) {
+       memset(line, 0, strlen(line));
+       sfree(line);
+       line = NULL;
+    }
     if (ret) {
        if (ret->keyblob) {
             memset(ret->keyblob, 0, ret->keyblob_size);