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-rw-r--r--drivers/ptp/ptp_chardev.c16
-rw-r--r--include/linux/posix-clock.h6
-rw-r--r--kernel/time/posix-clock.c3
-rw-r--r--tools/testing/selftests/ptp/testptp.c37
4 files changed, 46 insertions, 16 deletions
diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index bf6468c56419..4380e6ddb849 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -205,6 +205,10 @@ long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
case PTP_EXTTS_REQUEST:
case PTP_EXTTS_REQUEST2:
+ if ((pccontext->fp->f_mode & FMODE_WRITE) == 0) {
+ err = -EACCES;
+ break;
+ }
memset(&req, 0, sizeof(req));
if (copy_from_user(&req.extts, (void __user *)arg,
@@ -246,6 +250,10 @@ long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
case PTP_PEROUT_REQUEST:
case PTP_PEROUT_REQUEST2:
+ if ((pccontext->fp->f_mode & FMODE_WRITE) == 0) {
+ err = -EACCES;
+ break;
+ }
memset(&req, 0, sizeof(req));
if (copy_from_user(&req.perout, (void __user *)arg,
@@ -314,6 +322,10 @@ long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
case PTP_ENABLE_PPS:
case PTP_ENABLE_PPS2:
+ if ((pccontext->fp->f_mode & FMODE_WRITE) == 0) {
+ err = -EACCES;
+ break;
+ }
memset(&req, 0, sizeof(req));
if (!capable(CAP_SYS_TIME))
@@ -456,6 +468,10 @@ long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
case PTP_PIN_SETFUNC:
case PTP_PIN_SETFUNC2:
+ if ((pccontext->fp->f_mode & FMODE_WRITE) == 0) {
+ err = -EACCES;
+ break;
+ }
if (copy_from_user(&pd, (void __user *)arg, sizeof(pd))) {
err = -EFAULT;
break;
diff --git a/include/linux/posix-clock.h b/include/linux/posix-clock.h
index ef8619f48920..a500d3160fe8 100644
--- a/include/linux/posix-clock.h
+++ b/include/linux/posix-clock.h
@@ -95,10 +95,13 @@ struct posix_clock {
* struct posix_clock_context - represents clock file operations context
*
* @clk: Pointer to the clock
+ * @fp: Pointer to the file used to open the clock
* @private_clkdata: Pointer to user data
*
* Drivers should use struct posix_clock_context during specific character
- * device file operation methods to access the posix clock.
+ * device file operation methods to access the posix clock. In particular,
+ * the file pointer can be used to verify correct access mode for ioctl()
+ * calls.
*
* Drivers can store a private data structure during the open operation
* if they have specific information that is required in other file
@@ -106,6 +109,7 @@ struct posix_clock {
*/
struct posix_clock_context {
struct posix_clock *clk;
+ struct file *fp;
void *private_clkdata;
};
diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c
index 1af0bb2cc45c..fe963384d5c2 100644
--- a/kernel/time/posix-clock.c
+++ b/kernel/time/posix-clock.c
@@ -129,6 +129,7 @@ static int posix_clock_open(struct inode *inode, struct file *fp)
goto out;
}
pccontext->clk = clk;
+ pccontext->fp = fp;
if (clk->ops.open) {
err = clk->ops.open(pccontext, fp->f_mode);
if (err) {
@@ -251,7 +252,7 @@ static int pc_clock_adjtime(clockid_t id, struct __kernel_timex *tx)
if (err)
return err;
- if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
+ if (tx->modes && (cd.fp->f_mode & FMODE_WRITE) == 0) {
err = -EACCES;
goto out;
}
diff --git a/tools/testing/selftests/ptp/testptp.c b/tools/testing/selftests/ptp/testptp.c
index 58064151f2c8..edc08a4433fd 100644
--- a/tools/testing/selftests/ptp/testptp.c
+++ b/tools/testing/selftests/ptp/testptp.c
@@ -140,6 +140,7 @@ static void usage(char *progname)
" -H val set output phase to 'val' nanoseconds (requires -p)\n"
" -w val set output pulse width to 'val' nanoseconds (requires -p)\n"
" -P val enable or disable (val=1|0) the system clock PPS\n"
+ " -r open the ptp clock in readonly mode\n"
" -s set the ptp clock time from the system time\n"
" -S set the system time from the ptp clock time\n"
" -t val shift the ptp clock time by 'val' seconds\n"
@@ -188,6 +189,7 @@ int main(int argc, char *argv[])
int pin_index = -1, pin_func;
int pps = -1;
int seconds = 0;
+ int readonly = 0;
int settime = 0;
int channel = -1;
clockid_t ext_clockid = CLOCK_REALTIME;
@@ -200,7 +202,7 @@ int main(int argc, char *argv[])
progname = strrchr(argv[0], '/');
progname = progname ? 1+progname : argv[0];
- while (EOF != (c = getopt(argc, argv, "cd:e:f:F:ghH:i:k:lL:n:o:p:P:sSt:T:w:x:Xy:z"))) {
+ while (EOF != (c = getopt(argc, argv, "cd:e:f:F:ghH:i:k:lL:n:o:p:P:rsSt:T:w:x:Xy:z"))) {
switch (c) {
case 'c':
capabilities = 1;
@@ -252,6 +254,9 @@ int main(int argc, char *argv[])
case 'P':
pps = atoi(optarg);
break;
+ case 'r':
+ readonly = 1;
+ break;
case 's':
settime = 1;
break;
@@ -308,7 +313,7 @@ int main(int argc, char *argv[])
}
}
- fd = open(device, O_RDWR);
+ fd = open(device, readonly ? O_RDONLY : O_RDWR);
if (fd < 0) {
fprintf(stderr, "opening %s: %s\n", device, strerror(errno));
return -1;
@@ -436,14 +441,16 @@ int main(int argc, char *argv[])
}
if (extts) {
- memset(&extts_request, 0, sizeof(extts_request));
- extts_request.index = index;
- extts_request.flags = PTP_ENABLE_FEATURE;
- if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) {
- perror("PTP_EXTTS_REQUEST");
- extts = 0;
- } else {
- puts("external time stamp request okay");
+ if (!readonly) {
+ memset(&extts_request, 0, sizeof(extts_request));
+ extts_request.index = index;
+ extts_request.flags = PTP_ENABLE_FEATURE;
+ if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) {
+ perror("PTP_EXTTS_REQUEST");
+ extts = 0;
+ } else {
+ puts("external time stamp request okay");
+ }
}
for (; extts; extts--) {
cnt = read(fd, &event, sizeof(event));
@@ -455,10 +462,12 @@ int main(int argc, char *argv[])
event.t.sec, event.t.nsec);
fflush(stdout);
}
- /* Disable the feature again. */
- extts_request.flags = 0;
- if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) {
- perror("PTP_EXTTS_REQUEST");
+ if (!readonly) {
+ /* Disable the feature again. */
+ extts_request.flags = 0;
+ if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) {
+ perror("PTP_EXTTS_REQUEST");
+ }
}
}
generated by cgit (git 2.34.1) at 2025-08-08 12:29:31 +0000