Messages in this thread | | | Date | Wed, 8 Nov 2017 22:35:55 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH] kallsyms: don't leak address when printing symbol |
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On Thu, 9 Nov 2017 12:50:29 +1100 "Tobin C. Harding" <me@tobin.cc> wrote:
> Currently if a pointer is printed using %p[ssB] and the symbol is not > found (kallsyms_lookup() fails) then we print the actual address. This > leaks kernel addresses. We should instead print something _safe_. > > Print "<no-symbol>" instead of kernel address.
Ug, ftrace requires this to work as is, as it uses it to print some addresses that may or may not be a symbol.
If anything, can this return a success or failure if it were to find a symbol or not, and then something like ftrace could decide to use %x if it does not.
And yes, ftrace leaks kernel addresses all over the place, that's just the nature of tracing the kernel.
-- Steve
> > Signed-off-by: Tobin C. Harding <me@tobin.cc> > --- > kernel/kallsyms.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c > index 127e7cfafa55..182e7592be9c 100644 > --- a/kernel/kallsyms.c > +++ b/kernel/kallsyms.c > @@ -390,7 +390,7 @@ static int __sprint_symbol(char *buffer, unsigned long address, > address += symbol_offset; > name = kallsyms_lookup(address, &size, &offset, &modname, buffer); > if (!name) > - return sprintf(buffer, "0x%lx", address - symbol_offset); > + return sprintf(buffer, "<no-symbol>"); > > if (name != buffer) > strcpy(buffer, name);
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