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Fix JSON parsing error in console file descriptor communication #593

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Merged
merged 1 commit into from
Sep 9, 2025
Merged

Fix JSON parsing error in console file descriptor communication #593

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10 changes: 9 additions & 1 deletion src/cmsg.c
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Original file line number Diff line number Diff line change
Expand Up @@ -133,8 +133,16 @@ struct file_t recvfd(int sockfd)
msg.msg_controllen = sizeof(u.buf);

ssize_t ret = recvmsg(sockfd, &msg, 0);
if (ret < 0)
if (ret < 0) {
/* Add specific error information for debugging console fd issues */
fprintf(stderr, "recvfd: recvmsg failed: %m (sockfd=%d)\n", sockfd);
goto err;
}
if (ret >= TAG_BUFFER) {
fprintf(stderr, "recvfd: received data too large: %zd >= %d\n", ret, TAG_BUFFER);
errno = EMSGSIZE;
goto err;
}
file.name[ret] = '\0';

/* Shrink the buffer to what is effectively used. */
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51 changes: 45 additions & 6 deletions src/parent_pipe_fd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -43,13 +43,24 @@ void write_or_close_sync_fd(int *fd, int res, const char *message)
return;

_cleanup_free_ char *json = NULL;
if (message) {
if (message && strlen(message) > 0) {
_cleanup_free_ char *escaped_message = escape_json_string(message);
json = g_strdup_printf("{\"%s\": %d, \"message\": \"%s\"}\n", res_key, res, escaped_message);
if (escaped_message == NULL) {
/* Fallback to JSON without message if escaping fails */
json = g_strdup_printf("{\"%s\": %d}\n", res_key, res);
} else {
json = g_strdup_printf("{\"%s\": %d, \"message\": \"%s\"}\n", res_key, res, escaped_message);
}
} else {
json = g_strdup_printf("{\"%s\": %d}\n", res_key, res);
}

/* Ensure we have valid JSON before attempting to write */
if (json == NULL) {
/* Fallback to minimal valid JSON */
json = g_strdup_printf("{\"%s\": %d}\n", res_key, res);
}

len = strlen(json);
if (write_all(*fd, json, len) != len) {
if (errno == EPIPE) {
Expand All @@ -63,21 +74,49 @@ void write_or_close_sync_fd(int *fd, int res, const char *message)

static char *escape_json_string(const char *str)
{
if (str == NULL) {
return NULL;
}

size_t str_len = strlen(str);
if (str_len == 0) {
return g_strdup("");
}

const char *p = str;
GString *escaped = g_string_sized_new(strlen(str));
GString *escaped = g_string_sized_new(str_len * 2); /* Pre-allocate extra space for escaping */

if (escaped == NULL) {
return NULL;
}

while (*p != 0) {
char c = *p++;
unsigned char c = (unsigned char)*p++;

/* Handle standard JSON escape sequences */
if (c == '\\' || c == '"') {
g_string_append_c(escaped, '\\');
g_string_append_c(escaped, c);
} else if (c == '/') {
g_string_append_printf(escaped, "\\/");
} else if (c == '\n') {
g_string_append_printf(escaped, "\\n");
} else if (c == '\r') {
g_string_append_printf(escaped, "\\r");
} else if (c == '\t') {
g_string_append_printf(escaped, "\\t");
} else if ((c > 0 && c < 0x1f) || c == 0x7f) {
g_string_append_printf(escaped, "\\u00%02x", (guint)c);
} else if (c == '\b') {
g_string_append_printf(escaped, "\\b");
} else if (c == '\f') {
g_string_append_printf(escaped, "\\f");
} else if (c < 0x20 || c == 0x7f) {
/* Escape control characters */
g_string_append_printf(escaped, "\\u00%02x", c);
} else if (c >= 0x80) {
/* For non-ASCII characters, pass through as-is for UTF-8 compatibility */
g_string_append_c(escaped, c);
} else {
/* Regular ASCII characters */
g_string_append_c(escaped, c);
}
}
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