linux-kernel - [PATCH 4/4] kdb,kgdb: Allow arbitrary kgdb magic knock sequences

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1312225260-1028-5-git-send-email-jason.wessel@windriver.com>
Date:	Mon, 1 Aug 2011 14:01:00 -0500
From:	Jason Wessel <jason.wessel@...driver.com>
To:	<torvalds@...ux-foundation.org>
CC:	<linux-kernel@...r.kernel.org>,
	<kgdb-bugreport@...ts.sourceforge.net>
Subject: [PATCH 4/4] kdb,kgdb: Allow arbitrary kgdb magic knock sequences

The first packet that gdb sends when the kernel is in kdb mode seems
to change with every release of gdb.  Instead of continuing to add
many different gdb packets, change kdb to automatically look for any
thing that looks like a gdb packet.

Example 1 cold start test:
echo g > /proc/sysrq-trigger
$D#44+

Example 2 cold start test:
echo g > /proc/sysrq-trigger
$3#33

The second one should re-enter kdb's shell right away and is purely a
test.

Signed-off-by: Jason Wessel <jason.wessel@...driver.com>
---
 kernel/debug/kdb/kdb_io.c |   28 ++++++++++++++++++++--------
 1 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 0dbcdfb..4802eb5 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -31,15 +31,21 @@ char kdb_prompt_str[CMD_BUFLEN];
 
 int kdb_trap_printk;
 
-static void kgdb_transition_check(char *buffer)
+static int kgdb_transition_check(char *buffer)
 {
-	int slen = strlen(buffer);
-	if (strncmp(buffer, "$?#3f", slen) != 0 &&
-	    strncmp(buffer, "$qSupported", slen) != 0 &&
-	    strncmp(buffer, "+$qSupported", slen) != 0) {
+	if (buffer[0] != '+' && buffer[0] != '$') {
 		KDB_STATE_SET(KGDB_TRANS);
 		kdb_printf("%s", buffer);
+	} else {
+		int slen = strlen(buffer);
+		if (slen > 3 && buffer[slen - 3] == '#') {
+			kdb_gdb_state_pass(buffer);
+			strcpy(buffer, "kgdb");
+			KDB_STATE_SET(DOING_KGDB);
+			return 1;
+		}
 	}
+	return 0;
 }
 
 static int kdb_read_get_key(char *buffer, size_t bufsize)
@@ -251,6 +257,10 @@ poll_again:
 	case 13: /* enter */
 		*lastchar++ = '\n';
 		*lastchar++ = '\0';
+		if (!KDB_STATE(KGDB_TRANS)) {
+			KDB_STATE_SET(KGDB_TRANS);
+			kdb_printf("%s", buffer);
+		}
 		kdb_printf("\n");
 		return buffer;
 	case 4: /* Del */
@@ -382,10 +392,12 @@ poll_again:
 				 * printed characters if we think that
 				 * kgdb is connecting, until the check
 				 * fails */
-				if (!KDB_STATE(KGDB_TRANS))
-					kgdb_transition_check(buffer);
-				else
+				if (!KDB_STATE(KGDB_TRANS)) {
+					if (kgdb_transition_check(buffer))
+						return buffer;
+				} else {
 					kdb_printf("%c", key);
+				}
 			}
 			/* Special escape to kgdb */
 			if (lastchar - buffer >= 5 &&
-- 
1.7.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/