Hi Eramoto,
On Fri, Sep 29, 2017 at 7:40 AM, ERAMOTO Masaya
<eramoto.masaya@xxxxxxxxxxxxxx> wrote:
> If btmon and btproyx use a unix socket, which has a long pathname,
> then the buffer overflows occur 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)
>
> *** 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 0x401B74: strcpy (string3.h:110)
> by 0x401B74: open_unix (btproxy.c:625)
> by 0x401B74: main (btproxy.c:901)
Lets have the fixes separately, one for btmon and another for btproxy.
> This patch also gives an error and stops running when parsing command-line
> arguments, if the unix socket pathname is too long.
> ---
> monitor/control.c | 7 ++++++-
> monitor/main.c | 7 +++++++
> tools/btproxy.c | 17 ++++++++++++++---
> 3 files changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/monitor/control.c b/monitor/control.c
> index 9bbdc37..5a1b5e2 100644
> --- a/monitor/control.c
> +++ b/monitor/control.c
> @@ -1130,6 +1130,7 @@ static int server_fd = -1;
> void control_server(const char *path)
> {
> struct sockaddr_un addr;
> + size_t len;
> int fd;
>
> if (server_fd >= 0)
> @@ -1143,9 +1144,13 @@ void control_server(const char *path)
> return;
> }
>
> + len = strlen(path);
> + if (len > sizeof(addr.sun_path) - 1)
> + len = sizeof(addr.sun_path) - 1;
> +
Should we actually fail here or you are truncating the path on btproxy?
> 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..68ae821 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 +143,11 @@ int main(int argc, char *argv[])
> analyze_path = optarg;
> break;
> case 's':
> + if (strlen(optarg) >
> + sizeof(addr.sun_path) - 1) {
> + fprintf(stderr, "Socket too long\n");
> + return EXIT_FAILURE;
If this would fail here Im no sure what is the point of the check on
control_server? Btw, the message should probably be "Socket name too
long".
> + }
> control_server(optarg);
> break;
> case 'p':
> diff --git a/tools/btproxy.c b/tools/btproxy.c
> index f06661d..abe9ef8 100644
> --- a/tools/btproxy.c
> +++ b/tools/btproxy.c
> @@ -610,6 +610,7 @@ static void server_callback(int fd, uint32_t events, void *user_data)
> static int open_unix(const char *path)
> {
> struct sockaddr_un addr;
> + size_t len;
> int fd;
>
> unlink(path);
> @@ -620,9 +621,13 @@ static int open_unix(const char *path)
> return -1;
> }
>
> + len = strlen(path);
> + if (len > sizeof(addr.sun_path) - 1)
> + len = sizeof(addr.sun_path) - 1;
> +
> 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 Unix server socket");
> @@ -797,9 +802,15 @@ int main(int argc, char *argv[])
> server_address = "0.0.0.0";
> break;
> case 'u':
> - if (optarg)
> + if (optarg) {
> + struct sockaddr_un addr;
> unix_path = optarg;
> - else
> + if (strlen(unix_path) >
> + sizeof(addr.sun_path) - 1) {
> + fprintf(stderr, "Path too long\n");
> + return EXIT_FAILURE;
> + }
> + } else
> unix_path = "/tmp/bt-server-bredr";
> break;
> case 'p':
> --
> 2.7.4
>
> --
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--
Luiz Augusto von Dentz
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