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authorMike Galbraith <efault@gmx.de>2021-04-16 14:02:07 +0200
committerBorislav Petkov <bp@suse.de>2021-04-20 17:32:46 +0200
commit5849cdf8c120e3979c57d34be55b92d90a77a47e (patch)
tree5c434ec87c77a969ef4926ea3fbe3501af0ab40b
parentbf05bf16c76bb44ab5156223e1e58e26dfe30a88 (diff)
x86/crash: Fix crash_setup_memmap_entries() out-of-bounds access
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
-rw-r--r--arch/x86/kernel/crash.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index a8f3af257e26..b1deacbeb266 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -337,7 +337,7 @@ 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;