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author | Eric W. Biederman <ebiederm@xmission.com> | 2019-02-08 04:44:12 +0300 |
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committer | Eric W. Biederman <ebiederm@xmission.com> | 2019-05-23 00:53:48 +0300 |
commit | 70f1b0d34bdf03065fe869e93cc17cad1ea20c4a (patch) | |
tree | 0b92623a4e69cb5d01a607173236eb4b13c1b820 /drivers/usb | |
parent | a188339ca5a396acc588e5851ed7e19f66b0ebd9 (diff) | |
download | linux-70f1b0d34bdf03065fe869e93cc17cad1ea20c4a.tar.xz |
signal/usb: Replace kill_pid_info_as_cred with kill_pid_usb_asyncio
The usb support for asyncio encoded one of it's values in the wrong
field. It should have used si_value but instead used si_addr which is
not present in the _rt union member of struct siginfo.
The practical result of this is that on a 64bit big endian kernel
when delivering a signal to a 32bit process the si_addr field
is set to NULL, instead of the expected pointer value.
This issue can not be fixed in copy_siginfo_to_user32 as the usb
usage of the the _sigfault (aka si_addr) member of the siginfo
union when SI_ASYNCIO is set is incompatible with the POSIX and
glibc usage of the _rt member of the siginfo union.
Therefore replace kill_pid_info_as_cred with kill_pid_usb_asyncio a
dedicated function for this one specific case. There are no other
users of kill_pid_info_as_cred so this specialization should have no
impact on the amount of code in the kernel. Have kill_pid_usb_asyncio
take instead of a siginfo_t which is difficult and error prone, 3
arguments, a signal number, an errno value, and an address enconded as
a sigval_t. The encoding of the address as a sigval_t allows the
code that reads the userspace request for a signal to handle this
compat issue along with all of the other compat issues.
Add BUILD_BUG_ONs in kernel/signal.c to ensure that we can now place
the pointer value at the in si_pid (instead of si_addr). That is the
code now verifies that si_pid and si_addr always occur at the same
location. Further the code veries that for native structures a value
placed in si_pid and spilling into si_uid will appear in userspace in
si_addr (on a byte by byte copy of siginfo or a field by field copy of
siginfo). The code also verifies that for a 64bit kernel and a 32bit
userspace the 32bit pointer will fit in si_pid.
I have used the usbsig.c program below written by Alan Stern and
slightly tweaked by me to run on a big endian machine to verify the
issue exists (on sparc64) and to confirm the patch below fixes the issue.
/* usbsig.c -- test USB async signal delivery */
#define _GNU_SOURCE
#include <stdio.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <endian.h>
#include <linux/usb/ch9.h>
#include <linux/usbdevice_fs.h>
static struct usbdevfs_urb urb;
static struct usbdevfs_disconnectsignal ds;
static volatile sig_atomic_t done = 0;
void urb_handler(int sig, siginfo_t *info , void *ucontext)
{
printf("Got signal %d, signo %d errno %d code %d addr: %p urb: %p\n",
sig, info->si_signo, info->si_errno, info->si_code,
info->si_addr, &urb);
printf("%s\n", (info->si_addr == &urb) ? "Good" : "Bad");
}
void ds_handler(int sig, siginfo_t *info , void *ucontext)
{
printf("Got signal %d, signo %d errno %d code %d addr: %p ds: %p\n",
sig, info->si_signo, info->si_errno, info->si_code,
info->si_addr, &ds);
printf("%s\n", (info->si_addr == &ds) ? "Good" : "Bad");
done = 1;
}
int main(int argc, char **argv)
{
char *devfilename;
int fd;
int rc;
struct sigaction act;
struct usb_ctrlrequest *req;
void *ptr;
char buf[80];
if (argc != 2) {
fprintf(stderr, "Usage: usbsig device-file-name\n");
return 1;
}
devfilename = argv[1];
fd = open(devfilename, O_RDWR);
if (fd == -1) {
perror("Error opening device file");
return 1;
}
act.sa_sigaction = urb_handler;
sigemptyset(&act.sa_mask);
act.sa_flags = SA_SIGINFO;
rc = sigaction(SIGUSR1, &act, NULL);
if (rc == -1) {
perror("Error in sigaction");
return 1;
}
act.sa_sigaction = ds_handler;
sigemptyset(&act.sa_mask);
act.sa_flags = SA_SIGINFO;
rc = sigaction(SIGUSR2, &act, NULL);
if (rc == -1) {
perror("Error in sigaction");
return 1;
}
memset(&urb, 0, sizeof(urb));
urb.type = USBDEVFS_URB_TYPE_CONTROL;
urb.endpoint = USB_DIR_IN | 0;
urb.buffer = buf;
urb.buffer_length = sizeof(buf);
urb.signr = SIGUSR1;
req = (struct usb_ctrlrequest *) buf;
req->bRequestType = USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE;
req->bRequest = USB_REQ_GET_DESCRIPTOR;
req->wValue = htole16(USB_DT_DEVICE << 8);
req->wIndex = htole16(0);
req->wLength = htole16(sizeof(buf) - sizeof(*req));
rc = ioctl(fd, USBDEVFS_SUBMITURB, &urb);
if (rc == -1) {
perror("Error in SUBMITURB ioctl");
return 1;
}
rc = ioctl(fd, USBDEVFS_REAPURB, &ptr);
if (rc == -1) {
perror("Error in REAPURB ioctl");
return 1;
}
memset(&ds, 0, sizeof(ds));
ds.signr = SIGUSR2;
ds.context = &ds;
rc = ioctl(fd, USBDEVFS_DISCSIGNAL, &ds);
if (rc == -1) {
perror("Error in DISCSIGNAL ioctl");
return 1;
}
printf("Waiting for usb disconnect\n");
while (!done) {
sleep(1);
}
close(fd);
return 0;
}
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Oliver Neukum <oneukum@suse.com>
Fixes: v2.3.39
Cc: stable@vger.kernel.org
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'drivers/usb')
-rw-r--r-- | drivers/usb/core/devio.c | 48 |
1 files changed, 24 insertions, 24 deletions
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index fa783531ee88..a02448105527 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -63,7 +63,7 @@ struct usb_dev_state { unsigned int discsignr; struct pid *disc_pid; const struct cred *cred; - void __user *disccontext; + sigval_t disccontext; unsigned long ifclaimed; u32 disabled_bulk_eps; bool privileges_dropped; @@ -90,6 +90,7 @@ struct async { unsigned int ifnum; void __user *userbuffer; void __user *userurb; + sigval_t userurb_sigval; struct urb *urb; struct usb_memory *usbm; unsigned int mem_usage; @@ -582,22 +583,19 @@ static void async_completed(struct urb *urb) { struct async *as = urb->context; struct usb_dev_state *ps = as->ps; - struct kernel_siginfo sinfo; struct pid *pid = NULL; const struct cred *cred = NULL; unsigned long flags; - int signr; + sigval_t addr; + int signr, errno; spin_lock_irqsave(&ps->lock, flags); list_move_tail(&as->asynclist, &ps->async_completed); as->status = urb->status; signr = as->signr; if (signr) { - clear_siginfo(&sinfo); - sinfo.si_signo = as->signr; - sinfo.si_errno = as->status; - sinfo.si_code = SI_ASYNCIO; - sinfo.si_addr = as->userurb; + errno = as->status; + addr = as->userurb_sigval; pid = get_pid(as->pid); cred = get_cred(as->cred); } @@ -615,7 +613,7 @@ static void async_completed(struct urb *urb) spin_unlock_irqrestore(&ps->lock, flags); if (signr) { - kill_pid_info_as_cred(sinfo.si_signo, &sinfo, pid, cred); + kill_pid_usb_asyncio(signr, errno, addr, pid, cred); put_pid(pid); put_cred(cred); } @@ -1427,7 +1425,7 @@ find_memory_area(struct usb_dev_state *ps, const struct usbdevfs_urb *uurb) static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb, struct usbdevfs_iso_packet_desc __user *iso_frame_desc, - void __user *arg) + void __user *arg, sigval_t userurb_sigval) { struct usbdevfs_iso_packet_desc *isopkt = NULL; struct usb_host_endpoint *ep; @@ -1727,6 +1725,7 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb isopkt = NULL; as->ps = ps; as->userurb = arg; + as->userurb_sigval = userurb_sigval; if (as->usbm) { unsigned long uurb_start = (unsigned long)uurb->buffer; @@ -1801,13 +1800,17 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb static int proc_submiturb(struct usb_dev_state *ps, void __user *arg) { struct usbdevfs_urb uurb; + sigval_t userurb_sigval; if (copy_from_user(&uurb, arg, sizeof(uurb))) return -EFAULT; + memset(&userurb_sigval, 0, sizeof(userurb_sigval)); + userurb_sigval.sival_ptr = arg; + return proc_do_submiturb(ps, &uurb, (((struct usbdevfs_urb __user *)arg)->iso_frame_desc), - arg); + arg, userurb_sigval); } static int proc_unlinkurb(struct usb_dev_state *ps, void __user *arg) @@ -1977,7 +1980,7 @@ static int proc_disconnectsignal_compat(struct usb_dev_state *ps, void __user *a if (copy_from_user(&ds, arg, sizeof(ds))) return -EFAULT; ps->discsignr = ds.signr; - ps->disccontext = compat_ptr(ds.context); + ps->disccontext.sival_int = ds.context; return 0; } @@ -2005,13 +2008,17 @@ static int get_urb32(struct usbdevfs_urb *kurb, static int proc_submiturb_compat(struct usb_dev_state *ps, void __user *arg) { struct usbdevfs_urb uurb; + sigval_t userurb_sigval; if (get_urb32(&uurb, (struct usbdevfs_urb32 __user *)arg)) return -EFAULT; + memset(&userurb_sigval, 0, sizeof(userurb_sigval)); + userurb_sigval.sival_int = ptr_to_compat(arg); + return proc_do_submiturb(ps, &uurb, ((struct usbdevfs_urb32 __user *)arg)->iso_frame_desc, - arg); + arg, userurb_sigval); } static int processcompl_compat(struct async *as, void __user * __user *arg) @@ -2092,7 +2099,7 @@ static int proc_disconnectsignal(struct usb_dev_state *ps, void __user *arg) if (copy_from_user(&ds, arg, sizeof(ds))) return -EFAULT; ps->discsignr = ds.signr; - ps->disccontext = ds.context; + ps->disccontext.sival_ptr = ds.context; return 0; } @@ -2614,22 +2621,15 @@ const struct file_operations usbdev_file_operations = { static void usbdev_remove(struct usb_device *udev) { struct usb_dev_state *ps; - struct kernel_siginfo sinfo; while (!list_empty(&udev->filelist)) { ps = list_entry(udev->filelist.next, struct usb_dev_state, list); destroy_all_async(ps); wake_up_all(&ps->wait); list_del_init(&ps->list); - if (ps->discsignr) { - clear_siginfo(&sinfo); - sinfo.si_signo = ps->discsignr; - sinfo.si_errno = EPIPE; - sinfo.si_code = SI_ASYNCIO; - sinfo.si_addr = ps->disccontext; - kill_pid_info_as_cred(ps->discsignr, &sinfo, - ps->disc_pid, ps->cred); - } + if (ps->discsignr) + kill_pid_usb_asyncio(ps->discsignr, EPIPE, ps->disccontext, + ps->disc_pid, ps->cred); } } |