lkml.org 
[lkml]   [2022]   [Aug]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: strlcpy() notes (was Re: [GIT PULL] smb3 client fixes)
    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

    \
     
     \ /
      Last update: 2022-08-23 12:26    [W:3.352 / U:0.056 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site