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From: "Christopher M. Riedl" <cmr@informatik.wtf>
To: linuxppc-dev@ozlabs.org, kernel-hardening@lists.openwall.com
Cc: ajd@linux.ibm.com
Subject: [PATCH v5 1/2] powerpc/xmon: Allow listing and clearing breakpoints in read-only mode
Date: Tue, 27 Aug 2019 22:46:12 -0500	[thread overview]
Message-ID: <20190828034613.14750-2-cmr@informatik.wtf> (raw)
In-Reply-To: <20190828034613.14750-1-cmr@informatik.wtf>

Read-only mode should not prevent listing and clearing any active
breakpoints.

Signed-off-by: Christopher M. Riedl <cmr@informatik.wtf>
---
 arch/powerpc/xmon/xmon.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index d0620d762a5a..a98a354d46ac 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1045,10 +1045,6 @@ cmds(struct pt_regs *excp)
 			set_lpp_cmd();
 			break;
 		case 'b':
-			if (xmon_is_ro) {
-				printf(xmon_ro_msg);
-				break;
-			}
 			bpt_cmds();
 			break;
 		case 'C':
@@ -1317,11 +1313,16 @@ bpt_cmds(void)
 	struct bpt *bp;
 
 	cmd = inchar();
+
 	switch (cmd) {
 #ifndef CONFIG_PPC_8xx
 	static const char badaddr[] = "Only kernel addresses are permitted for breakpoints\n";
 	int mode;
 	case 'd':	/* bd - hardware data breakpoint */
+		if (xmon_is_ro) {
+			printf(xmon_ro_msg);
+			break;
+		}
 		if (!ppc_breakpoint_available()) {
 			printf("Hardware data breakpoint not supported on this cpu\n");
 			break;
@@ -1349,6 +1350,10 @@ bpt_cmds(void)
 		break;
 
 	case 'i':	/* bi - hardware instr breakpoint */
+		if (xmon_is_ro) {
+			printf(xmon_ro_msg);
+			break;
+		}
 		if (!cpu_has_feature(CPU_FTR_ARCH_207S)) {
 			printf("Hardware instruction breakpoint "
 			       "not supported on this cpu\n");
@@ -1407,7 +1412,7 @@ bpt_cmds(void)
 			break;
 		}
 		termch = cmd;
-		if (!scanhex(&a)) {
+		if (xmon_is_ro || !scanhex(&a)) {
 			/* print all breakpoints */
 			printf("   type            address\n");
 			if (dabr.enabled) {
-- 
2.23.0


  reply	other threads:[~2019-08-28  3:43 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-28  3:46 [PATCH v5 0/2] Restrict xmon when kernel is locked down Christopher M. Riedl
2019-08-28  3:46 ` Christopher M. Riedl [this message]
2019-08-29  6:40   ` [PATCH v5 1/2] powerpc/xmon: Allow listing and clearing breakpoints in read-only mode Daniel Axtens
2019-08-29 12:38     ` Christopher M Riedl
2019-08-28  3:46 ` [PATCH v5 2/2] powerpc/xmon: Restrict when kernel is locked down Christopher M. Riedl
2019-08-29  7:43   ` Daniel Axtens
2019-08-29 12:36     ` Christopher M Riedl

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