Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 55/56] perf/core: Fix possible Spectre-v1 indexing for ->aux_pages[] | Date | Mon, 14 May 2018 08:49:00 +0200 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Peter Zijlstra <peterz@infradead.org>
commit 4411ec1d1993e8dbff2898390e3fed280d88e446 upstream.
> kernel/events/ring_buffer.c:871 perf_mmap_to_page() warn: potential spectre issue 'rb->aux_pages'
Userspace controls @pgoff through the fault address. Sanitize the array index before doing the array dereference.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- kernel/events/ring_buffer.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -14,6 +14,7 @@ #include <linux/slab.h> #include <linux/circ_buf.h> #include <linux/poll.h> +#include <linux/nospec.h> #include "internal.h" @@ -779,8 +780,10 @@ perf_mmap_to_page(struct ring_buffer *rb return NULL; /* AUX space */ - if (pgoff >= rb->aux_pgoff) - return virt_to_page(rb->aux_pages[pgoff - rb->aux_pgoff]); + if (pgoff >= rb->aux_pgoff) { + int aux_pgoff = array_index_nospec(pgoff - rb->aux_pgoff, rb->aux_nr_pages); + return virt_to_page(rb->aux_pages[aux_pgoff]); + } } return __perf_mmap_to_page(rb, pgoff);
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