mirror of https://github.com/mkerrisk/man-pages
seccomp_unotify.2: EXAMPLES: some code modularity improvements
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Michael Kerrisk
parent
8bae56c220
commit
8760bd15a1
|
|
@ -1431,12 +1431,7 @@ targetProcess(int sockPair[2], char *argv[])
|
|||
static bool
|
||||
cookieIsValid(int notifyFd, uint64_t id)
|
||||
{
|
||||
if (ioctl(notifyFd, SECCOMP_IOCTL_NOTIF_ID_VALID, &id) == \-1) {
|
||||
perror("\etS: notification ID check failed!!!");
|
||||
return false;
|
||||
}
|
||||
|
||||
return true;
|
||||
return ioctl(notifyFd, SECCOMP_IOCTL_NOTIF_ID_VALID, &id) == 0;
|
||||
}
|
||||
|
||||
/* Access the memory of the target process in order to fetch the
|
||||
|
|
@ -1468,8 +1463,10 @@ getTargetPathname(struct seccomp_notif *req, int notifyFd,
|
|||
received a notification. If that process subsequently terminates,
|
||||
then read() on that file descriptor will return 0 (EOF). */
|
||||
|
||||
if (!cookieIsValid(notifyFd, req\->id))
|
||||
if (!cookieIsValid(notifyFd, req\->id)) {
|
||||
perror("\etS: notification ID check failed!!!");
|
||||
return false;
|
||||
}
|
||||
|
||||
/* Read bytes at the location containing the pathname argument */
|
||||
|
||||
|
|
@ -1495,8 +1492,10 @@ getTargetPathname(struct seccomp_notif *req, int notifyFd,
|
|||
are reading, since the target\(aqs memory may have been arbitrarily
|
||||
changed by subsequent operations. */
|
||||
|
||||
if (!cookieIsValid(notifyFd, req\->id))
|
||||
if (!cookieIsValid(notifyFd, req\->id)) {
|
||||
perror("\etS: notification ID check failed!!!");
|
||||
return false;
|
||||
}
|
||||
|
||||
/* Even if the target\(aqs system call was not interrupted by a signal,
|
||||
we have no guarantees about what was in the memory of the target
|
||||
|
|
@ -1512,25 +1511,25 @@ getTargetPathname(struct seccomp_notif *req, int notifyFd,
|
|||
return false;
|
||||
}
|
||||
|
||||
/* Handle notifications that arrive via the SECCOMP_RET_USER_NOTIF file
|
||||
descriptor, \(aqnotifyFd\(aq. */
|
||||
/* Allocate buffers for the seccomp user\-space notification request and
|
||||
response structures. It is the caller\(aqs responsibility to free the
|
||||
buffers returned via \(aqreq\(aq and \(aqresp\(aq. */
|
||||
|
||||
static void
|
||||
handleNotifications(int notifyFd)
|
||||
allocSeccompNotifBuffers(struct seccomp_notif **req,
|
||||
struct seccomp_notif_resp **resp,
|
||||
struct seccomp_notif_sizes *sizes)
|
||||
{
|
||||
struct seccomp_notif_sizes sizes;
|
||||
char path[PATH_MAX];
|
||||
|
||||
/* Discover the sizes of the structures that are used to receive
|
||||
notifications and send notification responses, and allocate
|
||||
buffers of those sizes. */
|
||||
|
||||
if (seccomp(SECCOMP_GET_NOTIF_SIZES, 0, &sizes) == \-1)
|
||||
errExit("\etS: seccomp\-SECCOMP_GET_NOTIF_SIZES");
|
||||
if (seccomp(SECCOMP_GET_NOTIF_SIZES, 0, sizes) == \-1)
|
||||
errExit("seccomp\-SECCOMP_GET_NOTIF_SIZES");
|
||||
|
||||
struct seccomp_notif *req = malloc(sizes.seccomp_notif);
|
||||
if (req == NULL)
|
||||
errExit("\etS: malloc");
|
||||
*req = malloc(sizes\->seccomp_notif);
|
||||
if (*req == NULL)
|
||||
errExit("malloc\-seccomp_notif");
|
||||
|
||||
/* When allocating the response buffer, we must allow for the fact
|
||||
that the user\-space binary may have been built with user\-space
|
||||
|
|
@ -1541,17 +1540,33 @@ handleNotifications(int notifyFd)
|
|||
structure that are past the response size that the kernel expects,
|
||||
then the supervisor is not touching an invalid memory location. */
|
||||
|
||||
size_t resp_size = sizes.seccomp_notif_resp;
|
||||
size_t resp_size = sizes\->seccomp_notif_resp;
|
||||
if (sizeof(struct seccomp_notif_resp) > resp_size)
|
||||
resp_size = sizeof(struct seccomp_notif_resp);
|
||||
|
||||
struct seccomp_notif_resp *resp = malloc(resp_size);
|
||||
*resp = malloc(resp_size);
|
||||
if (resp == NULL)
|
||||
errExit("\etS: malloc");
|
||||
errExit("malloc\-seccomp_notif_resp");
|
||||
|
||||
}
|
||||
|
||||
/* Handle notifications that arrive via the SECCOMP_RET_USER_NOTIF file
|
||||
descriptor, \(aqnotifyFd\(aq. */
|
||||
|
||||
static void
|
||||
handleNotifications(int notifyFd)
|
||||
{
|
||||
struct seccomp_notif_sizes sizes;
|
||||
struct seccomp_notif *req;
|
||||
struct seccomp_notif_resp *resp;
|
||||
char path[PATH_MAX];
|
||||
|
||||
allocSeccompNotifBuffers(&req, &resp, &sizes);
|
||||
|
||||
/* Loop handling notifications */
|
||||
|
||||
for (;;) {
|
||||
|
||||
/* Wait for next notification, returning info in \(aq*req\(aq */
|
||||
|
||||
memset(req, 0, sizes.seccomp_notif);
|
||||
|
|
@ -1642,15 +1657,18 @@ handleNotifications(int notifyFd)
|
|||
perror("ioctl\-SECCOMP_IOCTL_NOTIF_SEND");
|
||||
}
|
||||
|
||||
/* If the pathname is just "/bye", then the supervisor
|
||||
terminates. This allows us to see what happens if the
|
||||
target process makes further calls to mkdir(2). */
|
||||
/* If the pathname is just "/bye", then the supervisor breaks out
|
||||
of the loop and terminates. This allows us to see what happens
|
||||
if the target process makes further calls to mkdir(2). */
|
||||
|
||||
if (strcmp(path, "/bye") == 0) {
|
||||
printf("\etS: terminating **********\en");
|
||||
exit(EXIT_FAILURE);
|
||||
}
|
||||
if (strcmp(path, "/bye") == 0)
|
||||
break;
|
||||
}
|
||||
|
||||
free(req);
|
||||
free(resp);
|
||||
printf("\etS: terminating **********\en");
|
||||
exit(EXIT_FAILURE);
|
||||
}
|
||||
|
||||
/* Implementation of the supervisor process:
|
||||
|
|
|
|||
Loading…
Reference in New Issue