[Crash-utility] [PATCH 3/3] Fix a KASLR problem of sadump

[Takao Indoh]

This patch fix a problem that crash cannot open a dumpfile which can be
captured by sadump in KASLR enabled kernel.

The sadump dumpfile has register information in the header, therefore
this problem can be solved by the same way as virsh dump.

Signed-off-by: Takao Indoh <indou.takao at jp.fujitsu.com>
---
 defs.h    |  3 +++
 netdump.c |  3 +++
 sadump.c  | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 sadump.h  |  4 ++++
 symbols.c | 10 ++++++----
 5 files changed, 75 insertions(+), 5 deletions(-)

diff --git a/defs.h b/defs.h
index 558ab7b..2c84d73 100644
--- a/defs.h
+++ b/defs.h
@@ -6263,12 +6263,15 @@ FILE *set_sadump_fp(FILE *);
 void get_sadump_regs(struct bt_info *bt, ulong *ipp, ulong *spp);
 void sadump_display_regs(int, FILE *);
 int sadump_phys_base(ulong *);
+int sadump_set_phys_base(ulong);
 void sadump_show_diskset(void);
 int sadump_is_zero_excluded(void);
 void sadump_set_zero_excluded(void);
 void sadump_unset_zero_excluded(void);
 struct sadump_data;
 struct sadump_data *get_sadump_data(void);
+ulong sadump_get_idtr(void);
+ulong sadump_get_cr3(void);
 
 /*
  * qemu.c
diff --git a/netdump.c b/netdump.c
index b03ba13..b0ce160 100644
--- a/netdump.c
+++ b/netdump.c
@@ -5132,6 +5132,9 @@ calc_kaslr_offset(ulong *kaslr_offset, ulong *phys_base)
 	if (vmcore_kaslr_check()) {
 		idtr = qemu_get_idtr();
 		cr3 = qemu_get_cr3();
+	} else if (SADUMP_DUMPFILE()) {
+		idtr = sadump_get_idtr();
+		cr3 = sadump_get_cr3();
 	} else
 		return FALSE;
 
diff --git a/sadump.c b/sadump.c
index a96ba9c..d2a5c47 100644
--- a/sadump.c
+++ b/sadump.c
@@ -1558,15 +1558,27 @@ sadump_display_regs(int cpu, FILE *ofp)
  */
 int sadump_phys_base(ulong *phys_base)
 {
-	if (SADUMP_VALID()) {
+	if (SADUMP_VALID() && !sd->phys_base) {
 		if (CRASHDEBUG(1))
 			error(NOTE, "sadump: does not save phys_base.\n");
 		return FALSE;
 	}
 
+	if (sd->phys_base) {
+		*phys_base = sd->phys_base;
+		return TRUE;
+	}
+
 	return FALSE;
 }
 
+int sadump_set_phys_base(ulong phys_base)
+{
+	sd->phys_base = phys_base;
+
+	return TRUE;
+}
+
 /*
  *  Used by "sys" command to show diskset disk names.
  */
@@ -1649,3 +1661,49 @@ get_sadump_data(void)
 {
 	return sd;
 }
+
+static int
+get_sadump_smram_cpu_state_any(struct sadump_smram_cpu_state *smram)
+{
+	ulong offset;
+	struct sadump_header *sh = sd->dump_header;
+	int apicid;
+	struct sadump_smram_cpu_state scs, zero;
+
+	offset = sd->sub_hdr_offset + sizeof(uint32_t) +
+		 sd->dump_header->nr_cpus * sizeof(struct sadump_apic_state);
+
+	memset(&zero, 0, sizeof(zero));
+
+	for (apicid = 0; apicid < sh->nr_cpus; ++apicid) {
+		if (!read_device(&scs, sizeof(scs), &offset)) {
+			error(INFO, "sadump: cannot read sub header "
+			      "cpu_state\n");
+			return FALSE;
+		}
+		if (memcmp(&scs, &zero, sizeof(scs)) != 0) {
+			*smram = scs;
+			return TRUE;
+		}
+	}
+
+	return FALSE;
+}
+
+ulong
+sadump_get_idtr(void)
+{
+	struct sadump_smram_cpu_state scs;
+	get_sadump_smram_cpu_state_any(&scs);
+
+	return ((uint64_t)scs.IdtUpper)<<32 | (uint64_t)scs.IdtLower;
+}
+
+ulong
+sadump_get_cr3(void)
+{
+	struct sadump_smram_cpu_state scs;
+	get_sadump_smram_cpu_state_any(&scs);
+
+	return scs.Cr3;
+}
diff --git a/sadump.h b/sadump.h
index 7f8e384..66aa17e 100644
--- a/sadump.h
+++ b/sadump.h
@@ -219,6 +219,10 @@ struct sadump_data {
 	ulonglong backup_offset;
 
 	uint64_t max_mapnr;
+
+	ulong kaslr_offset;
+	ulong phys_base;
+	ulong cr3;
 };
 
 struct sadump_data *sadump_get_sadump_data(void);
diff --git a/symbols.c b/symbols.c
index 9e0c9df..38720b5 100644
--- a/symbols.c
+++ b/symbols.c
@@ -625,7 +625,7 @@ kaslr_init(void)
 		}
 	}
 
-	if (vmcore_kaslr_check())
+	if (vmcore_kaslr_check() || SADUMP_DUMPFILE())
 		kt->flags2 |= KASLR_CHECK;
 }
 
@@ -640,7 +640,7 @@ derive_kaslr_offset(bfd *abfd, int dynamic, bfd_byte *start, bfd_byte *end,
 	unsigned long relocate;
 	ulong _stext_relocated;
 
-	if (vmcore_kaslr_check()) {
+	if (vmcore_kaslr_check() || SADUMP_DUMPFILE()) {
 		ulong kaslr_offset = 0, phys_base = 0;
 
 		calc_kaslr_offset(&kaslr_offset, &phys_base);
@@ -650,8 +650,10 @@ derive_kaslr_offset(bfd *abfd, int dynamic, bfd_byte *start, bfd_byte *end,
 			kt->flags |= RELOC_SET;
 		}
 
-		if (phys_base)
+		if (phys_base) {
 			kdump_set_phys_base(phys_base);
+			sadump_set_phys_base(phys_base);
+		}
 
 		return;
 	}
@@ -12255,7 +12257,7 @@ numeric_forward(const void *P_x, const void *P_y)
 		}
 	}
 
-	if (vmcore_kaslr_check()) {
+	if (vmcore_kaslr_check() || SADUMP_DUMPFILE()) {
 		if (STREQ(x->name, "divide_error"))
 			st->divide_error_vmlinux = valueof(x);
 		else if (STREQ(y->name, "divide_error"))
-- 
2.9.5