scsi: fnic: Use scnprintf() for avoiding potential buffer overflow

Since snprintf() returns the would-be-output size instead of the actual
output size, the succeeding calls may go beyond the given buffer limit.
Fix it by replacing with scnprintf().

Link: https://lore.kernel.org/r/20200315094241.9086-4-tiwai@suse.de
Cc: "James E . J . Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K . Petersen" <martin.petersen@oracle.com>
Cc: Satish Kharat <satishkh@cisco.com>
Cc: Sesidhar Baddela <sebaddel@cisco.com>
Cc: Karan Tilak Kumar <kartilak@cisco.com>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/fnic/fnic_trace.c b/drivers/scsi/fnic/fnic_trace.c
index a0d01aea28f714d9a8350656d0dac5ce153f4e47..9d52d83161ed0c498a38476e06cc352f9e15aa0d 100644 (file)
--- a/drivers/scsi/fnic/fnic_trace.c
+++ b/drivers/scsi/fnic/fnic_trace.c
@@ -138,7 +138,7 @@ int fnic_get_trace_data(fnic_dbgfs_t *fnic_dbgfs_prt)
                         * Dump trace buffer entry to memory file
                         * and increment read index @rd_idx
                         */
-                       len += snprintf(fnic_dbgfs_prt->buffer + len,
+                       len += scnprintf(fnic_dbgfs_prt->buffer + len,
                                  (trace_max_pages * PAGE_SIZE * 3) - len,
                                  "%16llu.%09lu %-50s %8x %8x %16llx %16llx "
                                  "%16llx %16llx %16llx\n", (u64)val.tv_sec,
@@ -180,7 +180,7 @@ int fnic_get_trace_data(fnic_dbgfs_t *fnic_dbgfs_prt)
                         * Dump trace buffer entry to memory file
                         * and increment read index @rd_idx
                         */
-                       len += snprintf(fnic_dbgfs_prt->buffer + len,
+                       len += scnprintf(fnic_dbgfs_prt->buffer + len,
                                  (trace_max_pages * PAGE_SIZE * 3) - len,
                                  "%16llu.%09lu %-50s %8x %8x %16llx %16llx "
                                  "%16llx %16llx %16llx\n", (u64)val.tv_sec,
@@ -220,12 +220,12 @@ int fnic_get_stats_data(struct stats_debug_info *debug,
        struct timespec64 val1, val2;
 
        ktime_get_real_ts64(&val1);
-       len = snprintf(debug->debug_buffer + len, buf_size - len,
+       len = scnprintf(debug->debug_buffer + len, buf_size - len,
                "------------------------------------------\n"
                 "\t\tTime\n"
                "------------------------------------------\n");
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                "Current time :          [%lld:%ld]\n"
                "Last stats reset time:  [%lld:%09ld]\n"
                "Last stats read time:   [%lld:%ld]\n"
@@ -243,11 +243,11 @@ int fnic_get_stats_data(struct stats_debug_info *debug,
 
        stats->stats_timestamps.last_read_time = val1;
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                  "------------------------------------------\n"
                  "\t\tIO Statistics\n"
                  "------------------------------------------\n");
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                  "Number of Active IOs: %lld\nMaximum Active IOs: %lld\n"
                  "Number of IOs: %lld\nNumber of IO Completions: %lld\n"
                  "Number of IO Failures: %lld\nNumber of IO NOT Found: %lld\n"
@@ -280,16 +280,16 @@ int fnic_get_stats_data(struct stats_debug_info *debug,
                  (u64)atomic64_read(&stats->io_stats.io_btw_10000_to_30000_msec),
                  (u64)atomic64_read(&stats->io_stats.io_greater_than_30000_msec));
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                  "\nCurrent Max IO time : %lld\n",
                  (u64)atomic64_read(&stats->io_stats.current_max_io_time));
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                  "\n------------------------------------------\n"
                  "\t\tAbort Statistics\n"
                  "------------------------------------------\n");
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                  "Number of Aborts: %lld\n"
                  "Number of Abort Failures: %lld\n"
                  "Number of Abort Driver Timeouts: %lld\n"
@@ -318,12 +318,12 @@ int fnic_get_stats_data(struct stats_debug_info *debug,
                  (u64)atomic64_read(&stats->abts_stats.abort_issued_btw_50_to_60_sec),
                  (u64)atomic64_read(&stats->abts_stats.abort_issued_greater_than_60_sec));
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                  "\n------------------------------------------\n"
                  "\t\tTerminate Statistics\n"
                  "------------------------------------------\n");
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                  "Number of Terminates: %lld\n"
                  "Maximum Terminates: %lld\n"
                  "Number of Terminate Driver Timeouts: %lld\n"
@@ -337,12 +337,12 @@ int fnic_get_stats_data(struct stats_debug_info *debug,
                  (u64)atomic64_read(&stats->term_stats.terminate_io_not_found),
                  (u64)atomic64_read(&stats->term_stats.terminate_failures));
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                  "\n------------------------------------------\n"
                  "\t\tReset Statistics\n"
                  "------------------------------------------\n");
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                  "Number of Device Resets: %lld\n"
                  "Number of Device Reset Failures: %lld\n"
                  "Number of Device Reset Aborts: %lld\n"
@@ -368,12 +368,12 @@ int fnic_get_stats_data(struct stats_debug_info *debug,
                          &stats->reset_stats.fnic_reset_completions),
                  (u64)atomic64_read(&stats->reset_stats.fnic_reset_failures));
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                  "\n------------------------------------------\n"
                  "\t\tFirmware Statistics\n"
                  "------------------------------------------\n");
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                  "Number of Active FW Requests %lld\n"
                  "Maximum FW Requests: %lld\n"
                  "Number of FW out of resources: %lld\n"
@@ -383,12 +383,12 @@ int fnic_get_stats_data(struct stats_debug_info *debug,
                  (u64)atomic64_read(&stats->fw_stats.fw_out_of_resources),
                  (u64)atomic64_read(&stats->fw_stats.io_fw_errs));
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                  "\n------------------------------------------\n"
                  "\t\tVlan Discovery Statistics\n"
                  "------------------------------------------\n");
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                  "Number of Vlan Discovery Requests Sent %lld\n"
                  "Vlan Response Received with no FCF VLAN ID: %lld\n"
                  "No solicitations recvd after vlan set, expiry count: %lld\n"
@@ -398,7 +398,7 @@ int fnic_get_stats_data(struct stats_debug_info *debug,
                  (u64)atomic64_read(&stats->vlan_stats.sol_expiry_count),
                  (u64)atomic64_read(&stats->vlan_stats.flogi_rejects));
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                  "\n------------------------------------------\n"
                  "\t\tOther Important Statistics\n"
                  "------------------------------------------\n");
@@ -406,7 +406,7 @@ int fnic_get_stats_data(struct stats_debug_info *debug,
        jiffies_to_timespec64(stats->misc_stats.last_isr_time, &val1);
        jiffies_to_timespec64(stats->misc_stats.last_ack_time, &val2);
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                  "Last ISR time: %llu (%8llu.%09lu)\n"
                  "Last ACK time: %llu (%8llu.%09lu)\n"
                  "Max ISR jiffies: %llu\n"
@@ -452,7 +452,7 @@ int fnic_get_stats_data(struct stats_debug_info *debug,
                  (u64)atomic64_read(&stats->misc_stats.rport_not_ready),
                  (u64)atomic64_read(&stats->misc_stats.frame_errors));
 
-       len += snprintf(debug->debug_buffer + len, buf_size - len,
+       len += scnprintf(debug->debug_buffer + len, buf_size - len,
                        "Firmware reported port speed: %llu\n",
                        (u64)atomic64_read(
                                &stats->misc_stats.current_port_speed));
@@ -742,7 +742,7 @@ int fnic_fc_trace_get_data(fnic_dbgfs_t *fnic_dbgfs_prt, u8 rdata_flag)
        rd_idx = fc_trace_entries.rd_idx;
        wr_idx = fc_trace_entries.wr_idx;
        if (rdata_flag == 0) {
-               len += snprintf(fnic_dbgfs_prt->buffer + len,
+               len += scnprintf(fnic_dbgfs_prt->buffer + len,
                        (fnic_fc_trace_max_pages * PAGE_SIZE * 3) - len,
                        "Time Stamp (UTC)\t\t"
                        "Host No:   F Type:  len:     FCoE_FRAME:\n");
@@ -762,11 +762,11 @@ int fnic_fc_trace_get_data(fnic_dbgfs_t *fnic_dbgfs_prt, u8 rdata_flag)
                } else {
                        fc_trace = (char *)tdata;
                        for (j = 0; j < FC_TRC_SIZE_BYTES; j++) {
-                               len += snprintf(fnic_dbgfs_prt->buffer + len,
+                               len += scnprintf(fnic_dbgfs_prt->buffer + len,
                                (fnic_fc_trace_max_pages * PAGE_SIZE * 3)
                                - len, "%02x", fc_trace[j] & 0xff);
                        } /* for loop */
-                       len += snprintf(fnic_dbgfs_prt->buffer + len,
+                       len += scnprintf(fnic_dbgfs_prt->buffer + len,
                                (fnic_fc_trace_max_pages * PAGE_SIZE * 3) - len,
                                "\n");
                }
@@ -810,7 +810,7 @@ void copy_and_format_trace_data(struct fc_trace_hdr *tdata,
        time64_to_tm(tdata->time_stamp.tv_sec, 0, &tm);
 
        fmt = "%02d:%02d:%04ld %02d:%02d:%02d.%09lu ns%8x       %c%8x\t";
-       len += snprintf(fnic_dbgfs_prt->buffer + len,
+       len += scnprintf(fnic_dbgfs_prt->buffer + len,
                max_size - len,
                fmt,
                tm.tm_mon + 1, tm.tm_mday, tm.tm_year + 1900,
@@ -823,25 +823,25 @@ void copy_and_format_trace_data(struct fc_trace_hdr *tdata,
        for (j = 0; j < min_t(u8, tdata->frame_len,
                (u8)(FC_TRC_SIZE_BYTES - FC_TRC_HEADER_SIZE)); j++) {
                if (tdata->frame_type == FNIC_FC_LE) {
-                       len += snprintf(fnic_dbgfs_prt->buffer + len,
+                       len += scnprintf(fnic_dbgfs_prt->buffer + len,
                                max_size - len, "%c", fc_trace[j]);
                } else {
-                       len += snprintf(fnic_dbgfs_prt->buffer + len,
+                       len += scnprintf(fnic_dbgfs_prt->buffer + len,
                                max_size - len, "%02x", fc_trace[j] & 0xff);
-                       len += snprintf(fnic_dbgfs_prt->buffer + len,
+                       len += scnprintf(fnic_dbgfs_prt->buffer + len,
                                max_size - len, " ");
                        if (j == ethhdr_len ||
                                j == ethhdr_len + fcoehdr_len ||
                                j == ethhdr_len + fcoehdr_len + fchdr_len ||
                                (i > 3 && j%fchdr_len == 0)) {
-                               len += snprintf(fnic_dbgfs_prt->buffer
+                               len += scnprintf(fnic_dbgfs_prt->buffer
                                        + len, max_size - len,
                                        "\n\t\t\t\t\t\t\t\t");
                                i++;
                        }
                } /* end of else*/
        } /* End of for loop*/
-       len += snprintf(fnic_dbgfs_prt->buffer + len,
+       len += scnprintf(fnic_dbgfs_prt->buffer + len,
                max_size - len, "\n");
        *orig_len = len;
 }