diff options
| author | Mike Galbraith <efault@gmx.de> | 2021-04-16 14:02:07 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-04-28 12:05:47 +0200 |
| commit | cb717a3160ff0c7af33cf06f8c524b70e8e50b44 (patch) | |
| tree | 036e278bea1d3adb0820c5c76d4b4e0963c03141 | |
| parent | 5a6d3197d0cc0cd8751726ca3332e97af3bf334e (diff) | |
x86/crash: Fix crash_setup_memmap_entries() out-of-bounds access
commit 5849cdf8c120e3979c57d34be55b92d90a77a47e upstream.
Commit in Fixes: added support for kexec-ing a kernel on panic using a
new system call. As part of it, it does prepare a memory map for the new
kernel.
However, while doing so, it wrongly accesses memory it has not
allocated: it accesses the first element of the cmem->ranges[] array in
memmap_exclude_ranges() but it has not allocated the memory for it in
crash_setup_memmap_entries(). As KASAN reports:
BUG: KASAN: vmalloc-out-of-bounds in crash_setup_memmap_entries+0x17e/0x3a0
Write of size 8 at addr ffffc90000426008 by task kexec/1187
(gdb) list *crash_setup_memmap_entries+0x17e
0xffffffff8107cafe is in crash_setup_memmap_entries (arch/x86/kernel/crash.c:322).
317 unsigned long long mend)
318 {
319 unsigned long start, end;
320
321 cmem->ranges[0].start = mstart;
322 cmem->ranges[0].end = mend;
323 cmem->nr_ranges = 1;
324
325 /* Exclude elf header region */
326 start = image->arch.elf_load_addr;
(gdb)
Make sure the ranges array becomes a single element allocated.
[ bp: Write a proper commit message. ]
Fixes: dd5f726076cc ("kexec: support for kexec on panic using new system call")
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dave Young <dyoung@redhat.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/725fa3dc1da2737f0f6188a1a9701bead257ea9d.camel@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/kernel/crash.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c index 2c1910f6717e..a6d623e43d62 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -23,6 +23,7 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/vmalloc.h> +#include <linux/overflow.h> #include <asm/processor.h> #include <asm/hardirq.h> @@ -572,7 +573,7 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params) struct crash_memmap_data cmd; struct crash_mem *cmem; - cmem = vzalloc(sizeof(struct crash_mem)); + cmem = vzalloc(struct_size(cmem, ranges, 1)); if (!cmem) return -ENOMEM; |