From: Daniel Thompson <[email protected]> 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 <[email protected]> Reviewed-by: Douglas Anderson <[email protected]> Signed-off-by: Wenlin Kang <[email protected]> --- 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
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