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 9c84d02634c8612740b914c4a1c6d0d5e806b210..856fea46faf2c8f1a779bf248e86c643e3607087 100644 (file)
--- a/src/bin/lttng/commands/enable_channels.c
+++ b/src/bin/lttng/commands/enable_channels.c
@@ -244,7 +244,7 @@ static int enable_channel(char *session_name)
                void *extended_ptr;
 
                /* Validate channel name's length */
-               if (strlen(channel_name) >= NAME_MAX) {
+               if (strlen(channel_name) >= sizeof(chan_opts.name)) {
                        ERR("Channel name is too long (max. %zu characters)",
                                        sizeof(chan_opts.name) - 1);
                        error = 1;