Skip to content

in_tcp: Prevent truncation on incoming payloads #11531

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
edsiper merged 2 commits into from
Mar 21, 2026
+289 −14
Merged

in_tcp: Prevent truncation on incoming payloads #11531

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
6132c1f
in_tcp: Prevent integer truncation on incoming payloads
cosmo0920 Mar 10, 2026
5e89f38
tests: in_tcp: Add a test case for limiting large payloads
cosmo0920 Mar 10, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
80 changes: 66 additions & 14 deletions plugins/in_tcp/tcp_conn.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -28,8 +28,12 @@
#include "tcp.h"
#include "tcp_conn.h"

static inline void consume_bytes(char *buf, int bytes, int length)
static inline void consume_bytes(char *buf, size_t bytes, size_t length)
{
if (bytes == 0 || bytes > length) {
return;
}

memmove(buf, buf + bytes, length - bytes);
}

Expand Down Expand Up @@ -132,9 +136,11 @@ static inline int process_pack(struct tcp_conn *conn,
msgpack_unpacked_destroy(&result);

if (ret == FLB_EVENT_ENCODER_SUCCESS) {
flb_input_log_append(conn->ins, NULL, 0,
ctx->log_encoder->output_buffer,
ctx->log_encoder->output_length);
if (ctx->log_encoder->output_length > 0) {
flb_input_log_append(conn->ins, NULL, 0,
ctx->log_encoder->output_buffer,
ctx->log_encoder->output_length);
}
ret = 0;
}
else {
Expand All @@ -152,6 +158,7 @@ static ssize_t parse_payload_json(struct tcp_conn *conn)
int ret;
int out_size;
char *pack;
ssize_t processed;

ret = flb_pack_json_state(conn->buf_data, conn->buf_len,
&pack, &out_size, &conn->pack_state);
Expand All @@ -170,10 +177,23 @@ static ssize_t parse_payload_json(struct tcp_conn *conn)
}

/* Process the packaged JSON and return the last byte used */
process_pack(conn, pack, out_size);
if (out_size < 0) {
flb_free(pack);
return -1;
}

ret = process_pack(conn, pack, (size_t) out_size);
flb_free(pack);
if (ret < 0) {
return -1;
}

processed = conn->pack_state.last_byte;
if (processed < 0 || processed > conn->buf_len) {
return -1;
}

return conn->pack_state.last_byte;
return processed;
}

/*
Expand All @@ -183,8 +203,8 @@ static ssize_t parse_payload_json(struct tcp_conn *conn)
static ssize_t parse_payload_none(struct tcp_conn *conn)
{
int ret;
int len;
int sep_len;
size_t len;
size_t sep_len;
size_t consumed = 0;
char *buf;
char *s;
Expand All @@ -202,7 +222,7 @@ static ssize_t parse_payload_none(struct tcp_conn *conn)
flb_log_event_encoder_reset(ctx->log_encoder);

while ((s = strstr(buf, separator))) {
len = (s - buf);
len = (size_t) (s - buf);
if (len == 0) {
break;
}
Expand Down Expand Up @@ -237,9 +257,11 @@ static ssize_t parse_payload_none(struct tcp_conn *conn)
}

if (ret == FLB_EVENT_ENCODER_SUCCESS) {
flb_input_log_append(conn->ins, NULL, 0,
ctx->log_encoder->output_buffer,
ctx->log_encoder->output_length);
if (ctx->log_encoder->output_length > 0) {
flb_input_log_append(conn->ins, NULL, 0,
ctx->log_encoder->output_buffer,
ctx->log_encoder->output_length);
}
}
else {
flb_plg_error(ctx->ins, "log event encoding error : %d", ret);
Expand Down Expand Up @@ -336,7 +358,14 @@ int tcp_conn_event(void *data)
}
else if (ret_payload == -1) {
flb_pack_state_reset(&conn->pack_state);
flb_pack_state_init(&conn->pack_state);
if (flb_pack_state_init(&conn->pack_state) == -1) {
flb_plg_error(ctx->ins,
"fd=%i failed to reinitialize JSON parser state",
event->fd);
conn->pending_close = FLB_TRUE;
ret = -1;
goto cleanup;
}
conn->pack_state.multiple = FLB_TRUE;
ret = -1;
goto cleanup;
Expand All @@ -356,7 +385,30 @@ int tcp_conn_event(void *data)
}


consume_bytes(conn->buf_data, ret_payload, conn->buf_len);
if (ret_payload < 0 || ret_payload > conn->buf_len) {
flb_plg_warn(ctx->ins,
"fd=%i invalid payload consume length=%zd buf_len=%i",
event->fd, ret_payload, conn->buf_len);

if (ctx->format == FLB_TCP_FMT_JSON) {
flb_pack_state_reset(&conn->pack_state);
if (flb_pack_state_init(&conn->pack_state) == -1) {
flb_plg_error(ctx->ins,
"fd=%i failed to reinitialize JSON parser state",
event->fd);
conn->pending_close = FLB_TRUE;
ret = -1;
goto cleanup;
}
conn->pack_state.multiple = FLB_TRUE;
}
Comment thread
coderabbitai[bot] marked this conversation as resolved.

conn->buf_len = 0;
ret = -1;
goto cleanup;
}
Comment thread
coderabbitai[bot] marked this conversation as resolved.

consume_bytes(conn->buf_data, (size_t) ret_payload, (size_t) conn->buf_len);
conn->buf_len -= ret_payload;
conn->buf_data[conn->buf_len] = '\0';

Expand Down
Loading
Loading