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-rw-r--r--svr-authpubkey.c204
1 files changed, 108 insertions, 96 deletions
diff --git a/svr-authpubkey.c b/svr-authpubkey.c
index acc660d..6612194 100644
--- a/svr-authpubkey.c
+++ b/svr-authpubkey.c
@@ -188,6 +188,103 @@ static void send_msg_userauth_pk_ok(char* algo, unsigned int algolen,
}
+static int checkpubkey_line(buffer* line, int line_num, char* filename,
+ const char* algo, unsigned int algolen,
+ const unsigned char* keyblob, unsigned int keybloblen) {
+ buffer *options_buf = NULL;
+ unsigned int pos, len;
+ int ret = DROPBEAR_FAILURE;
+
+ if (line->len < MIN_AUTHKEYS_LINE) {
+ TRACE(("checkpubkey: line too short"))
+ return DROPBEAR_FAILURE; /* line is too short for it to be a valid key */
+ }
+
+ /* check the key type */
+ if (strncmp((const char *) buf_getptr(line, algolen), algo, algolen) != 0) {
+ int is_comment = 0;
+ unsigned char *options_start = NULL;
+ int options_len = 0;
+ int escape, quoted;
+
+ /* skip over any comments or leading whitespace */
+ while (line->pos < line->len) {
+ const char c = buf_getbyte(line);
+ if (c == ' ' || c == '\t') {
+ continue;
+ } else if (c == '#') {
+ is_comment = 1;
+ break;
+ }
+ buf_incrpos(line, -1);
+ break;
+ }
+ if (is_comment) {
+ /* next line */
+ goto out;
+ }
+
+ /* remember start of options */
+ options_start = buf_getptr(line, 1);
+ quoted = 0;
+ escape = 0;
+ options_len = 0;
+
+ /* figure out where the options are */
+ while (line->pos < line->len) {
+ const char c = buf_getbyte(line);
+ if (!quoted && (c == ' ' || c == '\t')) {
+ break;
+ }
+ escape = (!escape && c == '\\');
+ if (!escape && c == '"') {
+ quoted = !quoted;
+ }
+ options_len++;
+ }
+ options_buf = buf_new(options_len);
+ buf_putbytes(options_buf, options_start, options_len);
+
+ /* compare the algorithm. +3 so we have enough bytes to read a space and some base64 characters too. */
+ if (line->pos + algolen+3 > line->len) {
+ goto out;
+ }
+ if (strncmp((const char *) buf_getptr(line, algolen), algo, algolen) != 0) {
+ goto out;
+ }
+ }
+ buf_incrpos(line, algolen);
+
+ /* check for space (' ') character */
+ if (buf_getbyte(line) != ' ') {
+ TRACE(("checkpubkey: space character expected, isn't there"))
+ goto out;
+ }
+
+ /* truncate the line at the space after the base64 data */
+ pos = line->pos;
+ for (len = 0; line->pos < line->len; len++) {
+ if (buf_getbyte(line) == ' ') break;
+ }
+ buf_setpos(line, pos);
+ buf_setlen(line, line->pos + len);
+
+ TRACE(("checkpubkey: line pos = %d len = %d", line->pos, line->len))
+
+ ret = cmp_base64_key(keyblob, keybloblen, (const unsigned char *) algo, algolen, line, NULL);
+
+ if (ret == DROPBEAR_SUCCESS && options_buf) {
+ ret = svr_add_pubkey_options(options_buf, line_num, filename);
+ }
+
+out:
+ if (options_buf) {
+ buf_free(options_buf);
+ }
+ return ret;
+}
+
+
/* Checks whether a specified publickey (and associated algorithm) is an
* acceptable key for authentication */
/* Returns DROPBEAR_SUCCESS if key is ok for auth, DROPBEAR_FAILURE otherwise */
@@ -198,8 +295,7 @@ static int checkpubkey(char* algo, unsigned int algolen,
char * filename = NULL;
int ret = DROPBEAR_FAILURE;
buffer * line = NULL;
- unsigned int len, pos;
- buffer * options_buf = NULL;
+ unsigned int len;
int line_num;
uid_t origuid;
gid_t origgid;
@@ -254,12 +350,6 @@ static int checkpubkey(char* algo, unsigned int algolen,
/* iterate through the lines */
do {
- /* new line : potentially new options */
- if (options_buf) {
- buf_free(options_buf);
- options_buf = NULL;
- }
-
if (buf_getline(line, authfile) == DROPBEAR_FAILURE) {
/* EOF reached */
TRACE(("checkpubkey: authorized_keys EOF reached"))
@@ -267,91 +357,8 @@ static int checkpubkey(char* algo, unsigned int algolen,
}
line_num++;
- if (line->len < MIN_AUTHKEYS_LINE) {
- TRACE(("checkpubkey: line too short"))
- continue; /* line is too short for it to be a valid key */
- }
-
- /* check the key type - will fail if there are options */
- TRACE(("a line!"))
-
- if (strncmp((const char *) buf_getptr(line, algolen), algo, algolen) != 0) {
- int is_comment = 0;
- unsigned char *options_start = NULL;
- int options_len = 0;
- int escape, quoted;
-
- /* skip over any comments or leading whitespace */
- while (line->pos < line->len) {
- const char c = buf_getbyte(line);
- if (c == ' ' || c == '\t') {
- continue;
- } else if (c == '#') {
- is_comment = 1;
- break;
- }
- buf_incrpos(line, -1);
- break;
- }
- if (is_comment) {
- /* next line */
- continue;
- }
-
- /* remember start of options */
- options_start = buf_getptr(line, 1);
- quoted = 0;
- escape = 0;
- options_len = 0;
-
- /* figure out where the options are */
- while (line->pos < line->len) {
- const char c = buf_getbyte(line);
- if (!quoted && (c == ' ' || c == '\t')) {
- break;
- }
- escape = (!escape && c == '\\');
- if (!escape && c == '"') {
- quoted = !quoted;
- }
- options_len++;
- }
- options_buf = buf_new(options_len);
- buf_putbytes(options_buf, options_start, options_len);
-
- /* compare the algorithm. +3 so we have enough bytes to read a space and some base64 characters too. */
- if (line->pos + algolen+3 > line->len) {
- continue;
- }
- if (strncmp((const char *) buf_getptr(line, algolen), algo, algolen) != 0) {
- continue;
- }
- }
- buf_incrpos(line, algolen);
-
- /* check for space (' ') character */
- if (buf_getbyte(line) != ' ') {
- TRACE(("checkpubkey: space character expected, isn't there"))
- continue;
- }
-
- /* truncate the line at the space after the base64 data */
- pos = line->pos;
- for (len = 0; line->pos < line->len; len++) {
- if (buf_getbyte(line) == ' ') break;
- }
- buf_setpos(line, pos);
- buf_setlen(line, line->pos + len);
-
- TRACE(("checkpubkey: line pos = %d len = %d", line->pos, line->len))
-
- ret = cmp_base64_key(keyblob, keybloblen, (const unsigned char *) algo, algolen, line, NULL);
-
- if (ret == DROPBEAR_SUCCESS && options_buf) {
- ret = svr_add_pubkey_options(options_buf, line_num, filename);
- }
-
- if (ret == DROPBEAR_SUCCESS) {
+ if (checkpubkey_line(line, line_num, filename,
+ algo, algolen, keyblob, keybloblen) == DROPBEAR_SUCCESS) {
break;
}
@@ -367,9 +374,6 @@ out:
buf_free(line);
}
m_free(filename);
- if (options_buf) {
- buf_free(options_buf);
- }
TRACE(("leave checkpubkey: ret=%d", ret))
return ret;
}
@@ -465,4 +469,12 @@ static int checkfileperm(char * filename) {
return DROPBEAR_SUCCESS;
}
+#ifdef DROPBEAR_FUZZ
+int fuzz_checkpubkey_line(buffer* line, int line_num, char* filename,
+ const char* algo, unsigned int algolen,
+ const unsigned char* keyblob, unsigned int keybloblen) {
+ return checkpubkey_line(line, line_num, filename, algo, algolen, keyblob, keybloblen);
+}
+#endif
+
#endif
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-27 06:07:43 +0000