[PATCH v4] ptp: ocp: Limit signal/freq counts in show/store functions

Sagi Maimon
2025-05-11T15:42:40Z

The sysfs show/store operations could access uninitialized elements
in the freq_in[] and signal_out[] arrays, leading to NULL pointer
dereferences. This patch introduces u8 fields (nr_freq_in,
nr_signal_out) to track the number of initialized elements, capping
the maximum at 4 for each array. The show/store functions are updated
to respect these limits, preventing out-of-bounds access and ensuring
safe array handling.

Signed-off-by: Sagi Maimon <maimon.sagi@gmail.com>
---
Addressed comments from Vadim Fedorenko:
- https://www.spinics.net/lists/netdev/msg1090730.html
Changes since v3:
- in signal/freq show routine put constant string "UNSUPPORTED" in
output instead of returning error.
---
---
drivers/ptp/ptp_ocp.c | 40 +++++++++++++++++++++++++++++++++-------
1 file changed, 33 insertions(+), 7 deletions(-)

diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
index 2ccdca4f6960..14b4b3bebccd 100644
--- a/drivers/ptp/ptp_ocp.c
+++ b/drivers/ptp/ptp_ocp.c
@@ -315,6 +315,8 @@ struct ptp_ocp_serial_port {
#define OCP_BOARD_ID_LEN 13
#define OCP_SERIAL_LEN 6
#define OCP_SMA_NUM 4
+#define OCP_SIGNAL_NUM 4
+#define OCP_FREQ_NUM 4

enum {
PORT_GNSS,
@@ -342,8 +344,8 @@ struct ptp_ocp {
struct dcf_master_reg __iomem *dcf_out;
struct dcf_slave_reg __iomem *dcf_in;
struct tod_reg __iomem *nmea_out;
- struct frequency_reg __iomem *freq_in[4];
- struct ptp_ocp_ext_src *signal_out[4];
+ struct frequency_reg __iomem *freq_in[OCP_FREQ_NUM];
+ struct ptp_ocp_ext_src *signal_out[OCP_SIGNAL_NUM];
struct ptp_ocp_ext_src *pps;
struct ptp_ocp_ext_src *ts0;
struct ptp_ocp_ext_src *ts1;
@@ -378,10 +380,12 @@ struct ptp_ocp {
u32 utc_tai_offset;
u32 ts_window_adjust;
u64 fw_cap;
- struct ptp_ocp_signal signal[4];
+ struct ptp_ocp_signal signal[OCP_SIGNAL_NUM];
struct ptp_ocp_sma_connector sma[OCP_SMA_NUM];
const struct ocp_sma_op *sma_op;
struct dpll_device *dpll;
+ int signals_nr;
+ int freq_in_nr;
};

#define OCP_REQ_TIMESTAMP BIT(0)
@@ -2697,6 +2701,8 @@ ptp_ocp_fb_board_init(struct ptp_ocp *bp, struct ocp_resource *r)
bp->eeprom_map = fb_eeprom_map;
bp->fw_version = ioread32(&bp->image->version);
bp->sma_op = &ocp_fb_sma_op;
+ bp->signals_nr = 4;
+ bp->freq_in_nr = 4;

ptp_ocp_fb_set_version(bp);

@@ -2862,6 +2868,8 @@ ptp_ocp_art_board_init(struct ptp_ocp *bp, struct ocp_resource *r)
bp->fw_version = ioread32(&bp->reg->version);
bp->fw_tag = 2;
bp->sma_op = &ocp_art_sma_op;
+ bp->signals_nr = 4;
+ bp->freq_in_nr = 4;

/* Enable MAC serial port during initialisation */
iowrite32(1, &bp->board_config->mro50_serial_activate);
@@ -2888,6 +2896,8 @@ ptp_ocp_adva_board_init(struct ptp_ocp *bp, struct ocp_resource *r)
bp->flash_start = 0xA00000;
bp->eeprom_map = fb_eeprom_map;
bp->sma_op = &ocp_adva_sma_op;
+ bp->signals_nr = 2;
+ bp->freq_in_nr = 2;

version = ioread32(&bp->image->version);
/* if lower 16 bits are empty, this is the fw loader. */
@@ -3190,6 +3200,9 @@ signal_store(struct device *dev, struct device_attribute *attr,
if (!argv)
return -ENOMEM;

+ if (gen >= bp->signals_nr)
+ return -EINVAL;
+
err = -EINVAL;
s.duty = bp->signal[gen].duty;
s.phase = bp->signal[gen].phase;
@@ -3247,6 +3260,10 @@ signal_show(struct device *dev, struct device_attribute *attr, char *buf)
int i;

i = (uintptr_t)ea->var;
+
+ if (i >= bp->signals_nr)
+ return sysfs_emit(buf, "UNSUPPORTED\n");
+
signal = &bp->signal[i];

count = sysfs_emit(buf, "%llu %d %llu %d", signal->period,
@@ -3359,6 +3376,9 @@ seconds_store(struct device *dev, struct device_attribute *attr,
u32 val;
int err;

+ if (idx >= bp->freq_in_nr)
+ return -EINVAL;
+
err = kstrtou32(buf, 0, &val);
if (err)
return err;
@@ -3381,6 +3401,9 @@ seconds_show(struct device *dev, struct device_attribute *attr, char *buf)
int idx = (uintptr_t)ea->var;
u32 val;

+ if (idx >= bp->freq_in_nr)
+ return sysfs_emit(buf, "UNSUPPORTED\n");
+
val = ioread32(&bp->freq_in[idx]->ctrl);
if (val & 1)
val = (val >> 8) & 0xff;
@@ -3402,6 +3425,9 @@ frequency_show(struct device *dev, struct device_attribute *attr, char *buf)
int idx = (uintptr_t)ea->var;
u32 val;

+ if (idx >= bp->freq_in_nr)
+ return -EINVAL;
+
val = ioread32(&bp->freq_in[idx]->status);
if (val & FREQ_STATUS_ERROR)
return sysfs_emit(buf, "error\n");
@@ -4008,7 +4034,7 @@ _signal_summary_show(struct seq_file *s, struct ptp_ocp *bp, int nr)
{
struct signal_reg __iomem *reg = bp->signal_out[nr]->mem;
struct ptp_ocp_signal *signal = &bp->signal[nr];
- char label[8];
+ char label[16];
bool on;
u32 val;

@@ -4031,7 +4057,7 @@ static void
_frequency_summary_show(struct seq_file *s, int nr,
struct frequency_reg __iomem *reg)
{
- char label[8];
+ char label[16];
bool on;
u32 val;

@@ -4175,11 +4201,11 @@ ptp_ocp_summary_show(struct seq_file *s, void *data)
}

if (bp->fw_cap & OCP_CAP_SIGNAL)
- for (i = 0; i < 4; i++)
+ for (i = 0; i < bp->signals_nr; i++)
_signal_summary_show(s, bp, i);

if (bp->fw_cap & OCP_CAP_FREQ)
- for (i = 0; i < 4; i++)
+ for (i = 0; i < bp->freq_in_nr; i++)
_frequency_summary_show(s, i, bp->freq_in[i]);

if (bp->irig_out) {
--
2.47.0