The format specifier %p can leak kernel addresses while not valuing the kptr_restrict system settings. Use %pK instead of %p, which also evaluates whether kptr_restrict is set.
Signed-off-by: Divya Ponnusamy pdivya@codeaurora.org Signed-off-by: Daniel Rosenberg drosen@google.com Cc: stable stable@vger.kernel.org --- drivers/dma-buf/sync_debug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/dma-buf/sync_debug.c b/drivers/dma-buf/sync_debug.c index c4c8ecb24aa9..d8d340542a79 100644 --- a/drivers/dma-buf/sync_debug.c +++ b/drivers/dma-buf/sync_debug.c @@ -133,7 +133,7 @@ static void sync_print_sync_file(struct seq_file *s, char buf[128]; int i;
- seq_printf(s, "[%p] %s: %s\n", sync_file, + seq_printf(s, "[%pK] %s: %s\n", sync_file, sync_file_get_name(sync_file, buf, sizeof(buf)), sync_status_str(dma_fence_get_status(sync_file->fence)));
Quoting Daniel Rosenberg (2018-06-06 00:40:41)
The format specifier %p can leak kernel addresses while not valuing the kptr_restrict system settings. Use %pK instead of %p, which also evaluates whether kptr_restrict is set.
This is backwards though. You never care about the actual value here and the hashed pointer (%p) is always enough to provide an identifying token. -Chris
On Tue, Jun 05, 2018 at 04:40:41PM -0700, Daniel Rosenberg wrote:
The format specifier %p can leak kernel addresses while not valuing the kptr_restrict system settings. Use %pK instead of %p, which also evaluates whether kptr_restrict is set.
Signed-off-by: Divya Ponnusamy pdivya@codeaurora.org Signed-off-by: Daniel Rosenberg drosen@google.com Cc: stable stable@vger.kernel.org
drivers/dma-buf/sync_debug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/dma-buf/sync_debug.c b/drivers/dma-buf/sync_debug.c index c4c8ecb24aa9..d8d340542a79 100644 --- a/drivers/dma-buf/sync_debug.c +++ b/drivers/dma-buf/sync_debug.c @@ -133,7 +133,7 @@ static void sync_print_sync_file(struct seq_file *s, char buf[128]; int i;
- seq_printf(s, "[%p] %s: %s\n", sync_file,
- seq_printf(s, "[%pK] %s: %s\n", sync_file,
This is a root-only file, right? So it's not that bad of a problem. Also, by default, all %p pointers are now hashed so what really is leaking here?
And finally, why even print out a pointer at all? Why not just stick with the name and not worry about the pointer?
thanks,
greg k-h
linaro-mm-sig@lists.linaro.org
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Chris Wilson -
Daniel Rosenberg -
Greg KH