Patch attached:
Fix a bug in offset calculations when parsing /etc/hosts in resolv.c.
Formerly a miscalculation meant that having found the correct line, the code
was trashing its own result data.
Signed off by Philip Nye
diff --git a/libc/inet/resolv.c b/libc/inet/resolv.c
index 364a4b9..47bab75 100644
--- a/libc/inet/resolv.c
+++ b/libc/inet/resolv.c
@@ -335,7 +335,7 @@ Domain name in a message can be represented as either:
#define MAX_RECURSE 5
-#define MAXALIASES (6)
+#define MAXALIASES (4)
#define BUFSZ (80) /* one line */
#define SBUFSIZE (BUFSZ + 1 + (sizeof(char *) * MAXALIASES))
@@ -1587,6 +1587,11 @@ parser_t * __open_etc_hosts(void)
return parser;
}
+#define MINTOKENS 2 //dotted ip address + canonical name
+#define MAXTOKENS (MINTOKENS + MAXALIASES)
+#define HALISTOFF (sizeof(char*) * MAXTOKENS)
+#define INADDROFF (HALISTOFF + 2 * sizeof(char*))
+
int attribute_hidden __read_etc_hosts_r(
parser_t * parser,
const char *name,
@@ -1601,8 +1606,7 @@ int attribute_hidden __read_etc_hosts_r(
char **host_aliases;
char **tok = NULL;
struct in_addr *h_addr0 = NULL;
-#define ALIASOFF (sizeof(*host_aliases) * MAXALIASES + 2 * sizeof(char*))
- const size_t aliaslen = ALIASOFF +
+ const size_t aliaslen = INADDROFF +
#ifdef __UCLIBC_HAS_IPV6__
sizeof(struct in6_addr)
#else
@@ -1622,8 +1626,8 @@ int attribute_hidden __read_etc_hosts_r(
return errno;
}
/* Layout in buf:
- * char **alias for MAXALIAS aliases
- * char **h_addr_list[1] = {*in[6]_addr, NULL}
+ * char *alias[MAXTOKENS] = {address, name, aliases...}
+ * char **h_addr_list[1] = {*in[6]_addr, NULL}
* struct in[6]_addr
* char line_buffer[BUFSZ+];
*/
@@ -1632,7 +1636,7 @@ int attribute_hidden __read_etc_hosts_r(
parser->line_len = buflen - aliaslen;
*h_errnop = HOST_NOT_FOUND;
/* <ip>[[:space:]][<aliases>] */
- while (config_read(parser, &tok, MAXALIASES, 2, "# \t", PARSE_NORMAL)) {
+ while (config_read(parser, &tok, MAXTOKENS, MINTOKENS, "# \t",
PARSE_NORMAL)) {
result_buf->h_aliases = alias = host_aliases = tok+1;
if (action == GETHOSTENT) {
/* Return whatever the next entry happens to be. */
@@ -1650,9 +1654,9 @@ int attribute_hidden __read_etc_hosts_r(
}
found:
result_buf->h_name = *(result_buf->h_aliases++);
- result_buf->h_addr_list = (char**)(buf + ALIASOFF);
+ result_buf->h_addr_list = (char**)(buf + HALISTOFF);
*(result_buf->h_addr_list + 1) = '\0';
- h_addr0 = (struct in_addr*)(buf + ALIASOFF + 2 * sizeof
(char*));
+ h_addr0 = (struct in_addr*)(buf + INADDROFF);
result_buf->h_addr = (char*)h_addr0;
if (0) /* nothing */;
#ifdef __UCLIBC_HAS_IPV4__
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