From: Daniel Thompson <daniel.thomp...@linaro.org>

commit d228bee8201a7ea77c414f1298b2f572f42c6113 upstream

Currently the code to manage the kdb history buffer uses strncpy() to
copy strings to/and from the history and exhibits the classic "but
nobody ever told me that strncpy() doesn't always terminate strings"
bug. Modern gcc compilers recognise this bug and issue a warning.

In reality these calls will only abridge the copied string if kdb_read()
has *already* overflowed the command buffer. Thus the use of counted
copies here is only used to reduce the secondary effects of a bug
elsewhere in the code.

Therefore transitioning these calls into strscpy() (without checking
the return code) is appropriate.

Signed-off-by: Daniel Thompson <daniel.thomp...@linaro.org>
Reviewed-by: Douglas Anderson <diand...@chromium.org>
Signed-off-by: Wenlin Kang <wenlin.k...@windriver.com>
---
 kernel/debug/kdb/kdb_main.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index 9ecfa37c7fbf..bb5dec762b69 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -1103,12 +1103,12 @@ static int handle_ctrl_cmd(char *cmd)
        case CTRL_P:
                if (cmdptr != cmd_tail)
                        cmdptr = (cmdptr-1) % KDB_CMD_HISTORY_COUNT;
-               strncpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
+               strscpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
                return 1;
        case CTRL_N:
                if (cmdptr != cmd_head)
                        cmdptr = (cmdptr+1) % KDB_CMD_HISTORY_COUNT;
-               strncpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
+               strscpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
                return 1;
        }
        return 0;
@@ -1315,7 +1315,7 @@ static int kdb_local(kdb_reason_t reason, int error, 
struct pt_regs *regs,
                if (*cmdbuf != '\n') {
                        if (*cmdbuf < 32) {
                                if (cmdptr == cmd_head) {
-                                       strncpy(cmd_hist[cmd_head], cmd_cur,
+                                       strscpy(cmd_hist[cmd_head], cmd_cur,
                                                CMD_BUFLEN);
                                        *(cmd_hist[cmd_head] +
                                          strlen(cmd_hist[cmd_head])-1) = '\0';
@@ -1325,7 +1325,7 @@ static int kdb_local(kdb_reason_t reason, int error, 
struct pt_regs *regs,
                                cmdbuf = cmd_cur;
                                goto do_full_getstr;
                        } else {
-                               strncpy(cmd_hist[cmd_head], cmd_cur,
+                               strscpy(cmd_hist[cmd_head], cmd_cur,
                                        CMD_BUFLEN);
                        }
 
-- 
2.17.1

-=-=-=-=-=-=-=-=-=-=-=-
Links: You receive all messages sent to this group.
View/Reply Online (#9155): 
https://lists.yoctoproject.org/g/linux-yocto/message/9155
Mute This Topic: https://lists.yoctoproject.org/mt/78284911/21656
Group Owner: linux-yocto+ow...@lists.yoctoproject.org
Unsubscribe: https://lists.yoctoproject.org/g/linux-yocto/unsub 
[arch...@mail-archive.com]
-=-=-=-=-=-=-=-=-=-=-=-

Reply via email to