On Mittwoch, 16. Februar 2022 19:18:21 CET Vitaly Chikunov wrote:
> `struct dirent' returned from readdir(3) could be shorter (or longer)
> than `sizeof(struct dirent)', thus memcpy of sizeof length will overread
> into unallocated page causing SIGSEGV. Example stack trace:
> 
>  #0  0x00005555559ebeed v9fs_co_readdir_many (/usr/bin/qemu-system-x86_64 +
> 0x497eed) #1  0x00005555559ec2e9 v9fs_readdir (/usr/bin/qemu-system-x86_64
> + 0x4982e9) #2  0x0000555555eb7983 coroutine_trampoline
> (/usr/bin/qemu-system-x86_64 + 0x963983) #3  0x00007ffff73e0be0 n/a (n/a +
> 0x0)
> 
> While fixing this, provide a helper for any future `struct dirent' cloning.
> 
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/841
> Cc: qemu-sta...@nongnu.org
> Co-authored-by: Christian Schoenebeck <qemu_...@crudebyte.com>
> Reviewed-by: Dmitry V. Levin <l...@altlinux.org>
> Signed-off-by: Vitaly Chikunov <v...@altlinux.org>
> ---

Queued on 9p.next:
https://github.com/cschoenebeck/qemu/commits/9p.next

Thanks! I prepare a new PR now.

Best regards,
Christian Schoenebeck



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