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-rw-r--r--arch/x86/boot/compressed/kaslr.c41
-rw-r--r--arch/x86/boot/compressed/misc.c49
-rw-r--r--arch/x86/boot/compressed/misc.h22
3 files changed, 64 insertions, 48 deletions
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 54037c9f2def..5550546916be 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -463,17 +463,20 @@ static unsigned long find_random_virt_addr(unsigned long minimum,
* Since this function examines addresses much more numerically,
* it takes the input and output pointers as 'unsigned long'.
*/
-unsigned char *choose_random_location(unsigned long input,
- unsigned long input_size,
- unsigned long output,
- unsigned long output_size)
+void choose_random_location(unsigned long input,
+ unsigned long input_size,
+ unsigned long *output,
+ unsigned long output_size,
+ unsigned long *virt_addr)
{
- unsigned long choice = output;
unsigned long random_addr;
+ /* By default, keep output position unchanged. */
+ *virt_addr = *output;
+
if (cmdline_find_option_bool("nokaslr")) {
warn("KASLR disabled: 'nokaslr' on cmdline.");
- goto out;
+ return;
}
boot_params->hdr.loadflags |= KASLR_FLAG;
@@ -482,25 +485,25 @@ unsigned char *choose_random_location(unsigned long input,
initialize_identity_maps();
/* Record the various known unsafe memory ranges. */
- mem_avoid_init(input, input_size, output);
+ mem_avoid_init(input, input_size, *output);
/* Walk e820 and find a random address. */
- random_addr = find_random_phys_addr(output, output_size);
+ random_addr = find_random_phys_addr(*output, output_size);
if (!random_addr) {
warn("KASLR disabled: could not find suitable E820 region!");
- goto out;
+ } else {
+ /* Update the new physical address location. */
+ if (*output != random_addr) {
+ add_identity_map(random_addr, output_size);
+ *output = random_addr;
+ }
}
- /* Always enforce the minimum. */
- if (random_addr < choice)
- goto out;
-
- choice = random_addr;
-
- add_identity_map(choice, output_size);
-
/* This actually loads the identity pagetable on x86_64. */
finalize_identity_maps();
-out:
- return (unsigned char *)choice;
+
+ /* Pick random virtual address starting from LOAD_PHYSICAL_ADDR. */
+ if (IS_ENABLED(CONFIG_X86_64))
+ random_addr = find_random_virt_addr(LOAD_PHYSICAL_ADDR, output_size);
+ *virt_addr = random_addr;
}
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index f14db4e21654..b3c5a5f030ce 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -170,7 +170,8 @@ void __puthex(unsigned long value)
}
#if CONFIG_X86_NEED_RELOCS
-static void handle_relocations(void *output, unsigned long output_len)
+static void handle_relocations(void *output, unsigned long output_len,
+ unsigned long virt_addr)
{
int *reloc;
unsigned long delta, map, ptr;
@@ -182,11 +183,6 @@ static void handle_relocations(void *output, unsigned long output_len)
* and where it was actually loaded.
*/
delta = min_addr - LOAD_PHYSICAL_ADDR;
- if (!delta) {
- debug_putstr("No relocation needed... ");
- return;
- }
- debug_putstr("Performing relocations... ");
/*
* The kernel contains a table of relocation addresses. Those
@@ -198,6 +194,20 @@ static void handle_relocations(void *output, unsigned long output_len)
map = delta - __START_KERNEL_map;
/*
+ * 32-bit always performs relocations. 64-bit relocations are only
+ * needed if KASLR has chosen a different starting address offset
+ * from __START_KERNEL_map.
+ */
+ if (IS_ENABLED(CONFIG_X86_64))
+ delta = virt_addr - LOAD_PHYSICAL_ADDR;
+
+ if (!delta) {
+ debug_putstr("No relocation needed... ");
+ return;
+ }
+ debug_putstr("Performing relocations... ");
+
+ /*
* Process relocations: 32 bit relocations first then 64 bit after.
* Three sets of binary relocations are added to the end of the kernel
* before compression. Each relocation table entry is the kernel
@@ -250,7 +260,8 @@ static void handle_relocations(void *output, unsigned long output_len)
#endif
}
#else
-static inline void handle_relocations(void *output, unsigned long output_len)
+static inline void handle_relocations(void *output, unsigned long output_len,
+ unsigned long virt_addr)
{ }
#endif
@@ -327,7 +338,7 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
unsigned long output_len)
{
const unsigned long kernel_total_size = VO__end - VO__text;
- unsigned char *output_orig = output;
+ unsigned long virt_addr = (unsigned long)output;
/* Retain x86 boot parameters pointer passed from startup_32/64. */
boot_params = rmode;
@@ -366,13 +377,16 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
* the entire decompressed kernel plus relocation table, or the
* entire decompressed kernel plus .bss and .brk sections.
*/
- output = choose_random_location((unsigned long)input_data, input_len,
- (unsigned long)output,
- max(output_len, kernel_total_size));
+ choose_random_location((unsigned long)input_data, input_len,
+ (unsigned long *)&output,
+ max(output_len, kernel_total_size),
+ &virt_addr);
/* Validate memory location choices. */
if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
- error("Destination address inappropriately aligned");
+ error("Destination physical address inappropriately aligned");
+ if (virt_addr & (MIN_KERNEL_ALIGN - 1))
+ error("Destination virtual address inappropriately aligned");
#ifdef CONFIG_X86_64
if (heap > 0x3fffffffffffUL)
error("Destination address too large");
@@ -382,19 +396,16 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
#endif
#ifndef CONFIG_RELOCATABLE
if ((unsigned long)output != LOAD_PHYSICAL_ADDR)
- error("Wrong destination address");
+ error("Destination address does not match LOAD_PHYSICAL_ADDR");
+ if ((unsigned long)output != virt_addr)
+ error("Destination virtual address changed when not relocatable");
#endif
debug_putstr("\nDecompressing Linux... ");
__decompress(input_data, input_len, NULL, NULL, output, output_len,
NULL, error);
parse_elf(output);
- /*
- * 32-bit always performs relocations. 64-bit relocations are only
- * needed if kASLR has chosen a different load address.
- */
- if (!IS_ENABLED(CONFIG_X86_64) || output != output_orig)
- handle_relocations(output, output_len);
+ handle_relocations(output, output_len, virt_addr);
debug_putstr("done.\nBooting the kernel.\n");
return output;
}
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 09c4ddd02ac6..1c8355eadbd1 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -67,20 +67,22 @@ int cmdline_find_option_bool(const char *option);
#if CONFIG_RANDOMIZE_BASE
/* kaslr.c */
-unsigned char *choose_random_location(unsigned long input_ptr,
- unsigned long input_size,
- unsigned long output_ptr,
- unsigned long output_size);
+void choose_random_location(unsigned long input,
+ unsigned long input_size,
+ unsigned long *output,
+ unsigned long output_size,
+ unsigned long *virt_addr);
/* cpuflags.c */
bool has_cpuflag(int flag);
#else
-static inline
-unsigned char *choose_random_location(unsigned long input_ptr,
- unsigned long input_size,
- unsigned long output_ptr,
- unsigned long output_size)
+static inline void choose_random_location(unsigned long input,
+ unsigned long input_size,
+ unsigned long *output,
+ unsigned long output_size,
+ unsigned long *virt_addr)
{
- return (unsigned char *)output_ptr;
+ /* No change from existing output location. */
+ *virt_addr = *output;
}
#endif
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-04 22:39:23 +0000