[Makedumpfile PATCH 1/2] makedumpfile: add runtime kaslr offset if it exists
Pratyush Anand
panand at redhat.com
Wed Apr 26 23:15:15 PDT 2017
If we have to erase a symbol from vmcore whose address is not present in
vmcoreinfo, then we need to pass vmlinux as well to get the symbol
address.
When kaslr is enabled, virtual address of all the kernel symbols are
randomized with an offset. vmlinux always has a static address, but all
the arch specific calculation are based on run time kernel address. So
we need to find a way to translate symbol address from vmlinux to kernel
run time address.
without this patch:
# makedumpfile --split -d 5 -x vmlinux --config scrub.conf vmcore dumpfile_{1,2,3}
readpage_kdump_compressed: pfn(f97ea) is excluded from vmcore.
readmem: type_addr: 1, addr:f97eaff8, size:8
vtop4_x86_64: Can't get pml4 (page_dir:f97eaff8).
readmem: Can't convert a virtual address(ffffffff819f1284) to physical address.
readmem: type_addr: 0, addr:ffffffff819f1284, size:390
check_release: Can't get the address of system_utsname.
After this patch check_release() is ok, and also we are able to erase
symbol from vmcore.
Signed-off-by: Pratyush Anand <panand at redhat.com>
---
arch/x86_64.c | 23 +++++++++++++++++++++++
erase_info.c | 1 +
makedumpfile.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
makedumpfile.h | 15 +++++++++++++++
4 files changed, 83 insertions(+)
diff --git a/arch/x86_64.c b/arch/x86_64.c
index e978a36f8878..ab5aae8f1b26 100644
--- a/arch/x86_64.c
+++ b/arch/x86_64.c
@@ -33,6 +33,29 @@ get_xen_p2m_mfn(void)
return NOT_FOUND_LONG_VALUE;
}
+unsigned long
+get_kaslr_offset_x86_64(unsigned long vaddr)
+{
+ unsigned long sym_vmcoreinfo, sym_vmlinux;
+
+ if (!info->kaslr_offset) {
+ sym_vmlinux = get_symbol_addr("_stext");
+ if (sym_vmlinux == NOT_FOUND_SYMBOL)
+ return 0;
+ sym_vmcoreinfo = read_vmcoreinfo_symbol(STR_SYMBOL("_stext"));
+ info->kaslr_offset = sym_vmcoreinfo - sym_vmlinux;
+ }
+ if (vaddr >= __START_KERNEL_map &&
+ vaddr < __START_KERNEL_map + info->kaslr_offset)
+ return info->kaslr_offset;
+ else
+ /*
+ * TODO: we need to check if it is vmalloc/vmmemmap/module
+ * address, we will have different offset
+ */
+ return 0;
+}
+
static int
get_page_offset_x86_64(void)
{
diff --git a/erase_info.c b/erase_info.c
index f2ba9149e93e..60abfa1a1adf 100644
--- a/erase_info.c
+++ b/erase_info.c
@@ -1088,6 +1088,7 @@ resolve_config_entry(struct config_entry *ce, unsigned long long base_vaddr,
ce->line, ce->name);
return FALSE;
}
+ ce->sym_addr += get_kaslr_offset(ce->sym_addr);
ce->type_name = get_symbol_type_name(ce->name,
DWARF_INFO_GET_SYMBOL_TYPE,
&ce->size, &ce->type_flag);
diff --git a/makedumpfile.c b/makedumpfile.c
index 301772a8820c..7e78641917d7 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -3782,6 +3782,46 @@ free_for_parallel()
}
int
+find_kaslr_offsets()
+{
+ off_t offset;
+ unsigned long size;
+ int ret = FALSE;
+
+ get_vmcoreinfo(&offset, &size);
+
+ if (!(info->name_vmcoreinfo = strdup(FILENAME_VMCOREINFO))) {
+ MSG("Can't duplicate strings(%s).\n", FILENAME_VMCOREINFO);
+ return FALSE;
+ }
+ if (!copy_vmcoreinfo(offset, size))
+ goto out;
+
+ if (!open_vmcoreinfo("r"))
+ goto out;
+
+ unlink(info->name_vmcoreinfo);
+
+ /*
+ * This arch specific function should update info->kaslr_offset. If
+ * kaslr is not enabled then offset will be set to 0. arch specific
+ * function might need to read from vmcoreinfo, therefore we have
+ * called this function between open_vmcoreinfo() and
+ * close_vmcoreinfo()
+ */
+ get_kaslr_offset(SYMBOL(_stext));
+
+ close_vmcoreinfo();
+
+ ret = TRUE;
+out:
+ free(info->name_vmcoreinfo);
+ info->name_vmcoreinfo = NULL;
+
+ return ret;
+}
+
+int
initial(void)
{
off_t offset;
@@ -3833,6 +3873,9 @@ initial(void)
set_dwarf_debuginfo("vmlinux", NULL,
info->name_vmlinux, info->fd_vmlinux);
+ if (has_vmcoreinfo() && !find_kaslr_offsets())
+ return FALSE;
+
if (!get_symbol_info())
return FALSE;
@@ -11031,6 +11074,7 @@ main(int argc, char *argv[])
info->fd_memory = -1;
info->fd_dumpfile = -1;
info->fd_bitmap = -1;
+ info->kaslr_offset = 0;
initialize_tables();
/*
diff --git a/makedumpfile.h b/makedumpfile.h
index e32e567018f6..0d358be8caac 100644
--- a/makedumpfile.h
+++ b/makedumpfile.h
@@ -253,10 +253,14 @@ static inline int string_exists(char *s) { return (s ? TRUE : FALSE); }
#define SYMBOL_INIT(symbol, str_symbol) \
do { \
SYMBOL(symbol) = get_symbol_addr(str_symbol); \
+ if (SYMBOL(symbol) != NOT_FOUND_SYMBOL) \
+ SYMBOL(symbol) += info->kaslr_offset; \
} while (0)
#define SYMBOL_INIT_NEXT(symbol, str_symbol) \
do { \
SYMBOL(symbol) = get_next_symbol_addr(str_symbol); \
+ if (SYMBOL(symbol) != NOT_FOUND_SYMBOL) \
+ SYMBOL(symbol) += info->kaslr_offset; \
} while (0)
#define WRITE_SYMBOL(str_symbol, symbol) \
do { \
@@ -838,6 +842,7 @@ int get_xen_info_arm64(void);
#define get_phys_base() get_phys_base_arm64()
#define get_machdep_info() get_machdep_info_arm64()
#define get_versiondep_info() get_versiondep_info_arm64()
+#define get_kaslr_offset(X) FALSE
#define get_xen_basic_info_arch(X) get_xen_basic_info_arm64(X)
#define get_xen_info_arch(X) get_xen_info_arm64(X)
#define is_phys_addr(X) stub_true_ul(X)
@@ -851,6 +856,7 @@ unsigned long long vaddr_to_paddr_arm(unsigned long vaddr);
#define get_phys_base() get_phys_base_arm()
#define get_machdep_info() get_machdep_info_arm()
#define get_versiondep_info() stub_true()
+#define get_kaslr_offset(X) FALSE
#define vaddr_to_paddr(X) vaddr_to_paddr_arm(X)
#define is_phys_addr(X) stub_true_ul(X)
#endif /* arm */
@@ -863,11 +869,13 @@ unsigned long long vaddr_to_paddr_x86(unsigned long vaddr);
#define get_phys_base() stub_true()
#define get_machdep_info() get_machdep_info_x86()
#define get_versiondep_info() get_versiondep_info_x86()
+#define get_kaslr_offset(X) FALSE
#define vaddr_to_paddr(X) vaddr_to_paddr_x86(X)
#define is_phys_addr(X) stub_true_ul(X)
#endif /* x86 */
#ifdef __x86_64__
+unsigned long get_kaslr_offset_x86_64(unsigned long vaddr);
int get_phys_base_x86_64(void);
int get_machdep_info_x86_64(void);
int get_versiondep_info_x86_64(void);
@@ -876,6 +884,7 @@ unsigned long long vtop4_x86_64(unsigned long vaddr);
#define get_phys_base() get_phys_base_x86_64()
#define get_machdep_info() get_machdep_info_x86_64()
#define get_versiondep_info() get_versiondep_info_x86_64()
+#define get_kaslr_offset(X) get_kaslr_offset_x86_64(X)
#define vaddr_to_paddr(X) vtop4_x86_64(X)
#define is_phys_addr(X) stub_true_ul(X)
#endif /* x86_64 */
@@ -888,6 +897,7 @@ unsigned long long vaddr_to_paddr_ppc64(unsigned long vaddr);
#define get_phys_base() stub_true()
#define get_machdep_info() get_machdep_info_ppc64()
#define get_versiondep_info() get_versiondep_info_ppc64()
+#define get_kaslr_offset(X) FALSE
#define vaddr_to_paddr(X) vaddr_to_paddr_ppc64(X)
#define is_phys_addr(X) stub_true_ul(X)
#endif /* powerpc64 */
@@ -899,6 +909,7 @@ unsigned long long vaddr_to_paddr_ppc(unsigned long vaddr);
#define get_phys_base() stub_true()
#define get_machdep_info() get_machdep_info_ppc()
#define get_versiondep_info() stub_true()
+#define get_kaslr_offset(X) FALSE
#define vaddr_to_paddr(X) vaddr_to_paddr_ppc(X)
#define is_phys_addr(X) stub_true_ul(X)
#endif /* powerpc32 */
@@ -911,6 +922,7 @@ int is_iomem_phys_addr_s390x(unsigned long addr);
#define get_phys_base() stub_true()
#define get_machdep_info() get_machdep_info_s390x()
#define get_versiondep_info() stub_true()
+#define get_kaslr_offset(X) FALSE
#define vaddr_to_paddr(X) vaddr_to_paddr_s390x(X)
#define is_phys_addr(X) is_iomem_phys_addr_s390x(X)
#endif /* s390x */
@@ -923,6 +935,7 @@ unsigned long long vaddr_to_paddr_ia64(unsigned long vaddr);
#define get_machdep_info() get_machdep_info_ia64()
#define get_phys_base() get_phys_base_ia64()
#define get_versiondep_info() stub_true()
+#define get_kaslr_offset(X) FALSE
#define vaddr_to_paddr(X) vaddr_to_paddr_ia64(X)
#define VADDR_REGION(X) (((unsigned long)(X)) >> REGION_SHIFT)
#define is_phys_addr(X) stub_true_ul(X)
@@ -1152,6 +1165,7 @@ struct DumpInfo {
int vmemmap_psize;
int vmemmap_cnt;
struct ppc64_vmemmap *vmemmap_list;
+ unsigned long kaslr_offset;
/*
* page table info for ppc64
@@ -1803,6 +1817,7 @@ struct memory_range {
struct memory_range crash_reserved_mem[CRASH_RESERVED_MEM_NR];
int crash_reserved_mem_nr;
+unsigned long read_vmcoreinfo_symbol(char *str_symbol);
int readmem(int type_addr, unsigned long long addr, void *bufptr, size_t size);
int get_str_osrelease_from_vmlinux(void);
int read_vmcoreinfo_xen(void);
--
2.9.3
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