kdb: Eliminate strncpy() warnings by replacing with strscpy() (d228bee8) · Commits · 戴 / test

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.thompson@linaro.org> Reviewed-by:

Douglas Anderson <dianders@chromium.org>

kernel/debug/kdb/kdb_main.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -1102,12 +1102,12 @@ 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;
		@@ -1314,7 +1314,7 @@ do_full_getstr:
		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';
		@@ -1324,7 +1324,7 @@ do_full_getstr:
		cmdbuf = cmd_cur;
		goto do_full_getstr;
		} else {
		strncpy(cmd_hist[cmd_head], cmd_cur,
		strscpy(cmd_hist[cmd_head], cmd_cur,
		CMD_BUFLEN);
		}

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