diff mbox

[01/11] batctl: Fix possible buffer overflow when using strncat

Message ID 1378847522-13776-2-git-send-email-sven@narfation.org
State Accepted, archived
Commit f1e262c80941ab1b4342999cd200840db6683a62
Headers show

Commit Message

Sven Eckelmann Sept. 10, 2013, 9:11 p.m. UTC 
The length field (n) of strncat is used to specify the length of the buffer
without the \0 delimiter. strncat will add it even when it will write it to the
limit of n bytes was written.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 bat-hosts.c | 2 +-
 functions.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

Comments

Marek Lindner Sept. 11, 2013, 10:49 a.m. UTC | #1 
On Tuesday, September 10, 2013 11:11:52 PM Sven Eckelmann wrote:
> The length field (n) of strncat is used to specify the length of the buffer
> without the \0 delimiter. strncat will add it even when it will write it to
> the limit of n bytes was written.
> 
> Signed-off-by: Sven Eckelmann <sven@narfation.org>
> ---
>  bat-hosts.c | 2 +-
>  functions.c | 4 ++--
>  2 files changed, 3 insertions(+), 3 deletions(-)

Applied in revision f1e262c.

Thanks,
Marek
diff mbox

Patch

diff --git a/bat-hosts.c b/bat-hosts.c
index 04e7a9b..f0adb9c 100644
--- a/bat-hosts.c
+++ b/bat-hosts.c
@@ -194,7 +194,7 @@  void bat_hosts_init(int read_opt)
 
 			strncpy(confdir, homedir, CONF_DIR_LEN);
 			confdir[CONF_DIR_LEN - 1] = '\0';
-			strncat(confdir, &bat_hosts_path[i][1], CONF_DIR_LEN - strlen(confdir));
+			strncat(confdir, &bat_hosts_path[i][1], CONF_DIR_LEN - strlen(confdir) - 1);
 		} else {
 			strncpy(confdir, bat_hosts_path[i], CONF_DIR_LEN);
 			confdir[CONF_DIR_LEN - 1] = '\0';
diff --git a/functions.c b/functions.c
index cc05a48..0359287 100644
--- a/functions.c
+++ b/functions.c
@@ -180,7 +180,7 @@  int read_file(char *dir, char *fname, int read_opt,
 
 	strncpy(full_path, dir, strlen(dir));
 	full_path[strlen(dir)] = '\0';
-	strncat(full_path, fname, sizeof(full_path) - strlen(full_path));
+	strncat(full_path, fname, sizeof(full_path) - strlen(full_path) - 1);
 
 open:
 	line = 0;
@@ -305,7 +305,7 @@  int write_file(char *dir, char *fname, char *arg1, char *arg2)
 
 	strncpy(full_path, dir, strlen(dir));
 	full_path[strlen(dir)] = '\0';
-	strncat(full_path, fname, sizeof(full_path) - strlen(full_path));
+	strncat(full_path, fname, sizeof(full_path) - strlen(full_path) - 1);
 
 	fd = open(full_path, O_WRONLY);