Fix: Properly sanitize input parameter

The lttng client uses the sizeof the containing buffer, defined as
LTTNG_SYMBOL_NAME_LEN, for input string sanitation instead of libc defined
macro NAME_MAX. lttng-enable_channel improperly verified user input
and wrongly discarded valid input in case NAME_MAX was less than the
sizeof the containing buffer for the channel's name.
This patch also fixes potential buffer overflow caused by an improperly
bounded strcpy in the case where NAME_MAX would have been greater than
LTTNG_SYMBOL_NAME_LEN.

Signed-off-by: Yannick Lamarre <ylamarre@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/src/bin/lttng/commands/enable_channels.c b/src/bin/lttng/commands/enable_channels.c
index 66caa79a21257a33e9e055ff6504066355b06e75..ac8f8e63bf7f6edb016ae26f5dcbfcb23f675d74 100644 (file)
--- a/src/bin/lttng/commands/enable_channels.c
+++ b/src/bin/lttng/commands/enable_channels.c
@@ -212,7 +212,7 @@ static int enable_channel(char *session_name)
        channel_name = strtok(opt_channels, ",");
        while (channel_name != NULL) {
                /* Validate channel name's length */
-               if (strlen(channel_name) >= NAME_MAX) {
+               if (strlen(channel_name) >= sizeof(chan.name)) {
                        ERR("Channel name is too long (max. %zu characters)",
                                        sizeof(chan.name) - 1);
                        error = 1;