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9aafc1b018
The "buflen" value comes from the user and there is a potential that it
could be zero. In do_handle_to_path() we know that "handle->handle_bytes"
is non-zero and we do:
handle_dwords = handle->handle_bytes >> 2;
So values 1-3 become zero. Then in ovl_fh_to_dentry() we do:
int len = fh_len << 2;
So now len is in the "0,4-128" range and a multiple of 4. But if
"buflen" is zero it will try to copy negative bytes when we do the
memcpy in ovl_fid_to_fh().
memcpy(&fh->fb, fid, buflen - OVL_FH_WIRE_OFFSET);
And that will lead to a crash. Thanks to Amir Goldstein for his help
with this patch.
Fixes:
|
||
|---|---|---|
| .. | ||
| copy_up.c | ||
| dir.c | ||
| export.c | ||
| file.c | ||
| inode.c | ||
| Kconfig | ||
| Makefile | ||
| namei.c | ||
| overlayfs.h | ||
| ovl_entry.h | ||
| readdir.c | ||
| super.c | ||
| util.c | ||