Messages in this thread | | | Date | Thu, 13 Aug 2020 18:31:55 +0100 | From | Al Viro <> | Subject | Re: [PATCH][v2] proc: use vmalloc for our kernel buffer |
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On Thu, Aug 13, 2020 at 01:19:18PM -0400, Josef Bacik wrote:
> > in sunrpc proc_dodebug() turns into > > left -= snprintf(buffer, left, "0x%04x\n", ^^^^ left + 1, that is.
> > *(unsigned int *) table->data); > > and that's not the only example. > > > > We wouldn't even need the extra +1 part, since we're only copying in how > much the user wants anyway, we could just go ahead and convert this to > > left -= snprintf(buffer, left, "0x%04x\n", *(unsigned int *) table->data); > > and be fine, right? Or am I misunderstanding what you're looking for? Thanks,
snprintf() always produces a NUL-terminated string. And if you are passing 7 as len, you want 0xf0ad\n to be copied to user. For that you need 8 passed to snprintf, and 8-byte buffer given to it.
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