For kernel virtual address, need set LOAD_PHYSICAL_ADDR to be the default
offset if randomization failed. Because it will be used to check whether
a relocation handling need be done for x86_64 kaslr.
Signed-off-by: Baoquan He <b...@redhat.com>
---
arch/x86/boot/compressed/aslr.c | 32 ++++++++++++++++++--------------
arch/x86/boot/compressed/misc.c | 6 ++++--
arch/x86/boot/compressed/misc.h | 20 +++++++++++---------
3 files changed, 33 insertions(+), 25 deletions(-)
diff --git a/arch/x86/boot/compressed/aslr.c b/arch/x86/boot/compressed/aslr.c
index 091b118..20a5f23 100644
--- a/arch/x86/boot/compressed/aslr.c
+++ b/arch/x86/boot/compressed/aslr.c
@@ -317,12 +317,12 @@ static unsigned long find_random_virt_offset(unsigned
long size)
return slots_fetch_random();
}
-unsigned char *choose_kernel_location(unsigned char *input,
- unsigned long input_size,
- unsigned char *output,
- unsigned long output_size)
+void choose_kernel_location(unsigned char *input,
+ unsigned long input_size,
+ unsigned char **output,
+ unsigned long output_size,
+ unsigned char **virt_rand_offset)
{
- unsigned long choice = (unsigned long)output;
unsigned long random;
#ifdef CONFIG_HIBERNATION
@@ -342,17 +342,21 @@ unsigned char *choose_kernel_location(unsigned char
*input,
output_size);
/* Walk e820 and find a random address. */
- random = find_random_addr(choice, output_size);
- if (!random) {
+ random = find_random_addr((unsigned long)*output, output_size);
+ if (!random)
debug_putstr("KASLR could not find suitable E820 region...\n");
- goto out;
- }
-
/* Always enforce the minimum. */
- if (random < choice)
- goto out;
+ else if (random > (unsigned long)*output)
+ *output = (unsigned char*)random;
+
+
+ random = find_random_virt_offset(output_size);
+ if (!random)
+ debug_putstr("KASLR could not find suitable kernel mapping
region...\n");
+ else if (random > LOAD_PHYSICAL_ADDR)
+ *virt_rand_offset = (unsigned char*)random;
- choice = random;
out:
- return (unsigned char *)choice;
+ if (!random)
+ *virt_rand_offset = (unsigned char*)LOAD_PHYSICAL_ADDR;
}
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 324ccb5..acd4db1 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -373,6 +373,7 @@ asmlinkage __visible void *decompress_kernel(void *rmode,
memptr heap,
unsigned long output_len,
unsigned long run_size)
{
+ unsigned char *virt_rand_offset;
real_mode = rmode;
sanitize_boot_params(real_mode);
@@ -399,9 +400,10 @@ asmlinkage __visible void *decompress_kernel(void *rmode,
memptr heap,
* the entire decompressed kernel plus relocation table, or the
* entire decompressed kernel plus .bss and .brk sections.
*/
- output = choose_kernel_location(input_data, input_len, output,
+ choose_kernel_location(input_data, input_len, &output,
output_len > run_size ? output_len
- : run_size);
+ : run_size,
+ &virt_rand_offset);
/* Validate memory location choices. */
if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 24e3e56..7278bff 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -56,20 +56,22 @@ int cmdline_find_option_bool(const char *option);
#if CONFIG_RANDOMIZE_BASE
/* aslr.c */
-unsigned char *choose_kernel_location(unsigned char *input,
- unsigned long input_size,
- unsigned char *output,
- unsigned long output_size);
+void choose_kernel_location(unsigned char *input,
+ unsigned long input_size,
+ unsigned char **output,
+ unsigned long output_size,
+ unsigned char **virt_rand_offset);
/* cpuflags.c */
bool has_cpuflag(int flag);
#else
static inline
-unsigned char *choose_kernel_location(unsigned char *input,
- unsigned long input_size,
- unsigned char *output,
- unsigned long output_size)
+void choose_kernel_location(unsigned char *input,
+ unsigned long input_size,
+ unsigned char **output,
+ unsigned long output_size,
+ unsigned char **virt_rand_offset);
{
- return output;
+ return;
}
#endif
--
1.9.3
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