[PATCH 1/2] x86/crash: fix potential cmem->ranges array overflow
Yuntao Wang
ytcoode at gmail.com
Mon Dec 18 00:19:14 PST 2023
The max_nr_ranges field of cmem allocated in crash_setup_memmap_entries()
is not initialized, its default value is 0.
When elfcorehdr is allocated from the middle of crashk_res due to any
potential reason, that is, `image->elf_load_addr > crashk_res.start &&
image->elf_load_addr + image->elf_headers_sz - 1 < crashk_res.end`,
executing memmap_exclude_ranges() will cause a range split to occur in
crash_exclude_mem_range(), which eventually leads to an overflow of the
cmem->ranges array.
Set cmem->max_nr_ranges to 1 to make crash_exclude_mem_range() return
-ENOMEM instead of causing cmem->ranges array overflow even when a split
happens.
Signed-off-by: Yuntao Wang <ytcoode at gmail.com>
---
arch/x86/kernel/crash.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index c92d88680dbf..3be46f4b441e 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -282,10 +282,6 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
struct crash_memmap_data cmd;
struct crash_mem *cmem;
- cmem = vzalloc(struct_size(cmem, ranges, 1));
- if (!cmem)
- return -ENOMEM;
-
memset(&cmd, 0, sizeof(struct crash_memmap_data));
cmd.params = params;
@@ -321,6 +317,11 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
}
/* Exclude some ranges from crashk_res and add rest to memmap */
+ cmem = vzalloc(struct_size(cmem, ranges, 1));
+ if (!cmem)
+ return -ENOMEM;
+ cmem->max_nr_ranges = 1;
+
ret = memmap_exclude_ranges(image, cmem, crashk_res.start, crashk_res.end);
if (ret)
goto out;
--
2.43.0
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