Messages in this thread | | | Date | Thu, 11 Apr 2024 16:21:37 +0300 | From | Mike Rapoport <> | Subject | Re: [PATCH] init/main.c: Fix potential static_command_line memory overflow |
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On Thu, Apr 11, 2024 at 09:23:47AM +0200, Geert Uytterhoeven wrote: > CC Hiramatsu-san > > On Thu, Apr 11, 2024 at 5:25 AM Yuntao Wang <ytcoode@gmail.com> wrote: > > We allocate memory of size 'xlen + strlen(boot_command_line) + 1' for > > static_command_line, but the strings copied into static_command_line are > > extra_command_line and command_line, rather than extra_command_line and > > boot_command_line. > > > > When strlen(command_line) > strlen(boot_command_line), static_command_line > > will overflow.
Can this ever happen? Did you observe the overflow or is this a theoretical bug?
> > Fixes: f5c7310ac73e ("init/main: add checks for the return value of memblock_alloc*()")
f5c7310ac73e didn't have the logic for calculating allocation size, we surely don't want to go back that far wiht Fixes.
> > Signed-off-by: Yuntao Wang <ytcoode@gmail.com> > > --- > > init/main.c | 8 +++++--- > > 1 file changed, 5 insertions(+), 3 deletions(-) > > > > diff --git a/init/main.c b/init/main.c > > index 2ca52474d0c3..a7b1f5f3e3b6 100644 > > --- a/init/main.c > > +++ b/init/main.c > > @@ -625,11 +625,13 @@ static void __init setup_command_line(char *command_line) > > if (extra_init_args) > > ilen = strlen(extra_init_args) + 4; /* for " -- " */ > > > > - len = xlen + strlen(boot_command_line) + 1; > > + len = xlen + strlen(boot_command_line) + ilen + 1; > > > > - saved_command_line = memblock_alloc(len + ilen, SMP_CACHE_BYTES); > > + saved_command_line = memblock_alloc(len, SMP_CACHE_BYTES); > > if (!saved_command_line) > > - panic("%s: Failed to allocate %zu bytes\n", __func__, len + ilen); > > + panic("%s: Failed to allocate %zu bytes\n", __func__, len); > > + > > + len = xlen + strlen(command_line) + 1; > > > > static_command_line = memblock_alloc(len, SMP_CACHE_BYTES); > > if (!static_command_line) > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds
-- Sincerely yours, Mike.
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