Hi Eramoto,
On Wed, Oct 4, 2017 at 9:23 AM, ERAMOTO Masaya
<eramoto.masaya@xxxxxxxxxxxxxx> wrote:
> If btmon uses a unix socket, which has a long pathname, then the
> buffer overflow occurs as below:
>
> *** strcpy_chk: buffer overflow detected ***: program terminated
> at 0x4C3085C: ??? (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
> by 0x4C34E46: __strcpy_chk (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
> by 0x4084FE: strcpy (string3.h:110)
> by 0x4084FE: control_server (control.c:1148)
> by 0x4029E9: main (main.c:144)
>
> This patch also gives an error and stops running when parsing command-line
> arguments if the unix socket pathname is too long. And this patch adds the
> redundant check in control_server() to prevent the regression when reusing
> in the future.
> ---
> Changes in v2:
> - split v1 patch into this patch for btmon and another patch for btproxy.
> - move the check of pathname length before unlink()
> - fail in control_server() if pathname length is too long.
> - fix error message.
>
> monitor/control.c | 9 ++++++++-
> monitor/main.c | 6 ++++++
> 2 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/monitor/control.c b/monitor/control.c
> index 9bbdc37..1cd79ca 100644
> --- a/monitor/control.c
> +++ b/monitor/control.c
> @@ -1130,11 +1130,18 @@ static int server_fd = -1;
> void control_server(const char *path)
> {
> struct sockaddr_un addr;
> + size_t len;
> int fd;
>
> if (server_fd >= 0)
> return;
>
> + len = strlen(path);
> + if (len > sizeof(addr.sun_path) - 1) {
> + fprintf(stderr, "Socket name too long\n");
> + return;
> + }
> +
> unlink(path);
>
> fd = socket(PF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
> @@ -1145,7 +1152,7 @@ void control_server(const char *path)
>
> memset(&addr, 0, sizeof(addr));
> addr.sun_family = AF_UNIX;
> - strcpy(addr.sun_path, path);
> + strncpy(addr.sun_path, path, len);
>
> if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
> perror("Failed to bind server socket");
> diff --git a/monitor/main.c b/monitor/main.c
> index b4e9a6a..3e61a46 100644
> --- a/monitor/main.c
> +++ b/monitor/main.c
> @@ -31,6 +31,7 @@
> #include <stdlib.h>
> #include <string.h>
> #include <getopt.h>
> +#include <sys/un.h>
>
> #include "src/shared/mainloop.h"
> #include "src/shared/tty.h"
> @@ -114,6 +115,7 @@ int main(int argc, char *argv[])
>
> for (;;) {
> int opt;
> + struct sockaddr_un addr;
>
> opt = getopt_long(argc, argv, "d:r:w:a:s:p:i:tTSAE:vh",
> main_options, NULL);
> @@ -141,6 +143,10 @@ int main(int argc, char *argv[])
> analyze_path = optarg;
> break;
> case 's':
> + if (strlen(optarg) > sizeof(addr.sun_path) - 1) {
> + fprintf(stderr, "Socket name too long\n");
> + return EXIT_FAILURE;
> + }
> control_server(optarg);
> break;
> case 'p':
> --
> 2.7.4
Applied, thanks.
--
Luiz Augusto von Dentz
--
To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
