* [PATCH] linux-user: implement TARGET_SO_PEERSEC
@ 2020-02-03 17:37 Laurent Vivier
2020-02-04 21:10 ` Laurent Vivier
0 siblings, 1 reply; 2+ messages in thread
From: Laurent Vivier @ 2020-02-03 17:37 UTC (permalink / raw)
To: qemu-devel; +Cc: Riku Voipio, Laurent Vivier, Matthias Lüscher
"The purpose of this option is to allow an application to obtain the
security credentials of a Unix stream socket peer. It is analogous to
SO_PEERCRED (which provides authentication using standard Unix credentials
of pid, uid and gid), and extends this concept to other security
models." -- https://lwn.net/Articles/62370/
Until now it was passed to the kernel with an "int" argument and
fails when it was supported by the host because the parameter is
like a filename: it is always a \0-terminated string with no embedded
\0 characters, but is not guaranteed to be ASCII or UTF-8.
I've tested the option with the following program:
/*
* cc -o getpeercon getpeercon.c
*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
int main(void)
{
int fd;
struct sockaddr_in server, addr;
int ret;
socklen_t len;
char buf[256];
fd = socket(PF_INET, SOCK_STREAM, 0);
if (fd == -1) {
perror("socket");
return 1;
}
server.sin_family = AF_INET;
inet_aton("127.0.0.1", &server.sin_addr);
server.sin_port = htons(40390);
connect(fd, (struct sockaddr*)&server, sizeof(server));
len = sizeof(buf);
ret = getsockopt(fd, SOL_SOCKET, SO_PEERSEC, buf, &len);
if (ret == -1) {
perror("getsockopt");
return 1;
}
printf("%d %s\n", len, buf);
return 0;
}
On host:
$ ./getpeercon
33 system_u:object_r:unlabeled_t:s0
With qemu-aarch64/bionic without the patch:
$ ./getpeercon
getsockopt: Numerical result out of range
With the patch:
$ ./getpeercon
33 system_u:object_r:unlabeled_t:s0
Bug: https://bugs.launchpad.net/qemu/+bug/1823790
Reported-by: Matthias Lüscher <lueschem@gmail.com>
Tested-by: Matthias Lüscher <lueschem@gmail.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
linux-user/syscall.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index d60142f0691c..5f37e62772de 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -2344,6 +2344,28 @@ static abi_long do_getsockopt(int sockfd, int level, int optname,
}
break;
}
+ case TARGET_SO_PEERSEC: {
+ char *name;
+
+ if (get_user_u32(len, optlen)) {
+ return -TARGET_EFAULT;
+ }
+ if (len < 0) {
+ return -TARGET_EINVAL;
+ }
+ name = lock_user(VERIFY_WRITE, optval_addr, len, 0);
+ if (!name) {
+ return -TARGET_EFAULT;
+ }
+ lv = len;
+ ret = get_errno(getsockopt(sockfd, level, SO_PEERSEC,
+ name, &lv));
+ if (put_user_u32(lv, optlen)) {
+ ret = -TARGET_EFAULT;
+ }
+ unlock_user(name, optval_addr, 0);
+ break;
+ }
case TARGET_SO_LINGER:
{
struct linger lg;
--
2.24.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] linux-user: implement TARGET_SO_PEERSEC
2020-02-03 17:37 [PATCH] linux-user: implement TARGET_SO_PEERSEC Laurent Vivier
@ 2020-02-04 21:10 ` Laurent Vivier
0 siblings, 0 replies; 2+ messages in thread
From: Laurent Vivier @ 2020-02-04 21:10 UTC (permalink / raw)
To: qemu-devel; +Cc: Riku Voipio, Matthias Lüscher
Le 03/02/2020 à 18:37, Laurent Vivier a écrit :
> "The purpose of this option is to allow an application to obtain the
> security credentials of a Unix stream socket peer. It is analogous to
> SO_PEERCRED (which provides authentication using standard Unix credentials
> of pid, uid and gid), and extends this concept to other security
> models." -- https://lwn.net/Articles/62370/
>
> Until now it was passed to the kernel with an "int" argument and
> fails when it was supported by the host because the parameter is
> like a filename: it is always a \0-terminated string with no embedded
> \0 characters, but is not guaranteed to be ASCII or UTF-8.
>
> I've tested the option with the following program:
>
> /*
> * cc -o getpeercon getpeercon.c
> */
>
> #include <stdio.h>
> #include <sys/types.h>
> #include <sys/socket.h>
> #include <netinet/in.h>
> #include <arpa/inet.h>
>
> int main(void)
> {
> int fd;
> struct sockaddr_in server, addr;
> int ret;
> socklen_t len;
> char buf[256];
>
> fd = socket(PF_INET, SOCK_STREAM, 0);
> if (fd == -1) {
> perror("socket");
> return 1;
> }
>
> server.sin_family = AF_INET;
> inet_aton("127.0.0.1", &server.sin_addr);
> server.sin_port = htons(40390);
>
> connect(fd, (struct sockaddr*)&server, sizeof(server));
>
> len = sizeof(buf);
> ret = getsockopt(fd, SOL_SOCKET, SO_PEERSEC, buf, &len);
> if (ret == -1) {
> perror("getsockopt");
> return 1;
> }
> printf("%d %s\n", len, buf);
> return 0;
> }
>
> On host:
>
> $ ./getpeercon
> 33 system_u:object_r:unlabeled_t:s0
>
> With qemu-aarch64/bionic without the patch:
>
> $ ./getpeercon
> getsockopt: Numerical result out of range
>
> With the patch:
>
> $ ./getpeercon
> 33 system_u:object_r:unlabeled_t:s0
>
> Bug: https://bugs.launchpad.net/qemu/+bug/1823790
> Reported-by: Matthias Lüscher <lueschem@gmail.com>
> Tested-by: Matthias Lüscher <lueschem@gmail.com>
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> ---
> linux-user/syscall.c | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index d60142f0691c..5f37e62772de 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -2344,6 +2344,28 @@ static abi_long do_getsockopt(int sockfd, int level, int optname,
> }
> break;
> }
> + case TARGET_SO_PEERSEC: {
> + char *name;
> +
> + if (get_user_u32(len, optlen)) {
> + return -TARGET_EFAULT;
> + }
> + if (len < 0) {
> + return -TARGET_EINVAL;
> + }
> + name = lock_user(VERIFY_WRITE, optval_addr, len, 0);
> + if (!name) {
> + return -TARGET_EFAULT;
> + }
> + lv = len;
> + ret = get_errno(getsockopt(sockfd, level, SO_PEERSEC,
> + name, &lv));
> + if (put_user_u32(lv, optlen)) {
> + ret = -TARGET_EFAULT;
> + }
> + unlock_user(name, optval_addr, 0);
There is an error here, "0" must be "lv".
I update and resend.
Thanks,
Laurent
^ permalink raw reply [flat|nested] 2+ messages in thread
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