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
Hi Eramoto,
On Wed, Oct 4, 2017 at 9:23 AM, ERAMOTO Masaya
<[email protected]> 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
btproyx with a unix socket has the similar problem as btmon as below.
So this patch fixes btproxy by the similar way as btmon.
*** 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)
---
Changes in v2:
- split v1 patch into this patch for btproxy and another patch for btmon.
- move the check of pathname length before unlink()
- fail in open_unix() if pathname length is too long.
tools/btproxy.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/tools/btproxy.c b/tools/btproxy.c
index f06661d..ae0ff74 100644
--- a/tools/btproxy.c
+++ b/tools/btproxy.c
@@ -610,8 +610,15 @@ 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;
+ len = strlen(path);
+ if (len > sizeof(addr.sun_path) - 1) {
+ fprintf(stderr, "Path too long\n");
+ return -1;
+ }
+
unlink(path);
fd = socket(PF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
@@ -622,7 +629,7 @@ static int open_unix(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 Unix server socket");
@@ -797,9 +804,16 @@ 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