diff options
| author | Baoquan He <bhe@redhat.com> | 2017-06-27 14:39:06 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-06-30 08:53:14 +0200 |
| commit | 8eabf42ae5237e6b699aeac687b5b629e3537c8d (patch) | |
| tree | 8c44cf4bae96bf80da05770b0212dff252c27e9e | |
| parent | x86/boot/KASLR: Add checking for the offset of kernel virtual address randomi... (diff) | |
| download | linux-8eabf42ae5237e6b699aeac687b5b629e3537c8d.tar.xz linux-8eabf42ae5237e6b699aeac687b5b629e3537c8d.zip | |
x86/boot/KASLR: Fix kexec crash due to 'virt_addr' calculation bug
Kernel text KASLR is separated into physical address and virtual
address randomization. And for virtual address randomization, we
only randomiza to get an offset between 16M and KERNEL_IMAGE_SIZE.
So the initial value of 'virt_addr' should be LOAD_PHYSICAL_ADDR,
but not the original kernel loading address 'output'.
The bug will cause kernel boot failure if kernel is loaded at a different
position than the address, 16M, which is decided at compiled time.
Kexec/kdump is such practical case.
To fix it, just assign LOAD_PHYSICAL_ADDR to virt_addr as initial
value.
Tested-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 8391c73 ("x86/KASLR: Randomize virtual address separately")
Link: http://lkml.kernel.org/r/1498567146-11990-3-git-send-email-bhe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/boot/compressed/kaslr.c | 3 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/misc.c | 4 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/misc.h | 2 |
3 files changed, 2 insertions, 7 deletions
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index 54c24f0a43d3..56a7e9201741 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -564,9 +564,6 @@ void choose_random_location(unsigned long input, { unsigned long random_addr, min_addr; - /* By default, keep output position unchanged. */ - *virt_addr = *output; - if (cmdline_find_option_bool("nokaslr")) { warn("KASLR disabled: 'nokaslr' on cmdline."); return; diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index 6008fa9b74d9..00241c815524 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -338,7 +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 long virt_addr = (unsigned long)output; + unsigned long virt_addr = LOAD_PHYSICAL_ADDR; /* Retain x86 boot parameters pointer passed from startup_32/64. */ boot_params = rmode; @@ -399,7 +399,7 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap, #ifndef CONFIG_RELOCATABLE if ((unsigned long)output != LOAD_PHYSICAL_ADDR) error("Destination address does not match LOAD_PHYSICAL_ADDR"); - if ((unsigned long)output != virt_addr) + if (virt_addr != LOAD_PHYSICAL_ADDR) error("Destination virtual address changed when not relocatable"); #endif diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index 1c8355eadbd1..766a5211f827 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -81,8 +81,6 @@ static inline void choose_random_location(unsigned long input, unsigned long output_size, unsigned long *virt_addr) { - /* No change from existing output location. */ - *virt_addr = *output; } #endif |