Re: strlcpy() notes (was Re: [GIT PULL] smb3 client fixes)

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Sun, Aug 21, 2022 at 11:13:28AM -0700, Linus Torvalds wrote:
> It's also worth pointing out that the kernel implementation of
> 'strscpy()' will not do the chunk-sized accesses across an unaligned
> page boundary. So it won't actually take a page fault past the
> terminating NUL character, but if you pass it an 'N' that is bigger
> than the source buffer, and you have sub-page faults in the kernel, we
> might need to do some further work in this are. Catalin?

We can probably hit sub-page faults if the function reads past the end
of a string. Strange that we haven't hit any so far (well, it needs
KASAN_HW_TAGS enabled, it doesn't get as much coverage).

With load_unaligned_zeropad(), the arm64 implementation disables tag
checking temporarily. We could do the same with read_word_at_a_time()
(there is a kasan_check_read() in this function but it wrongly uses a
size of 1).

I'll send a patch but most likely next week (I'm still on holiday).

-- 
Catalin



[Index of Archives]     [Linux Kernel]     [Kernel Newbies]     [x86 Platform Driver]     [Netdev]     [Linux Wireless]     [Netfilter]     [Bugtraq]     [Linux Filesystems]     [Yosemite Discussion]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Device Mapper]

  Powered by Linux