Date: Tue, 28 Nov 2017 09:30:16 +1100 From: "Tobin C. Harding" <me@...in.cc> To: kernel-hardening@...ts.openwall.com Cc: "Tobin C. Harding" <me@...in.cc>, linux-kernel@...r.kernel.org, Network Development <netdev@...r.kernel.org>, Steven Rostedt <rostedt@...dmis.org>, Tycho Andersen <tycho@...ho.ws> Subject: [RFC 0/3] kallsyms: don't leak address when printing symbol This is an RFC for two reasons. 1) I don't know who this patch set may break? 2) Patch set includes a function that is not called. Function is there to facilitate fixing breakages. _If_ no one gets broken then we can remove the unused function. Thanks for looking at this. 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 potentially leaks kernel addresses. We could instead print something _safe_. If kallsyms is made to return an error then callers of sprint_symbol() can decide what to do. In the case of vsprintf we can print '<no-symbol>' (patch 2). In the case of trace we want the address so we can check the return code and print the address if no symbol is found (patch 3). Design for this set loosely suggested by Steve Rostedt (so as not to break ftrace). Patch 1 and 2 tested, patch 3 (trace stuff) untested :) thanks, Tobin. Tobin C. Harding (3): kallsyms: don't leak address when symbol not found vsprintf: print <no-symbol> if symbol not found trace: print address if symbol not found include/linux/kernel.h | 2 ++ kernel/kallsyms.c | 6 ++++-- kernel/trace/trace.h | 24 ++++++++++++++++++++++++ kernel/trace/trace_events_hist.c | 6 +++--- lib/vsprintf.c | 18 +++++++++++++++--- 5 files changed, 48 insertions(+), 8 deletions(-) -- 2.7.4
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