Re: [PATCH] perf: prevent overflow in size calculation

From: Cody P Schafer
Date: Thu Jul 19 2012 - 22:51:40 EST

+ /* Check for overflow when calculating sizeof_sym_hist */
+ if (size > (SIZE_MAX / sizeof(u64)))
+ return -1;

How does it guarantee that the end result which used in zalloc below
would not overflow?

+ sizeof_sym_hist = (sizeof(struct sym_hist) + size * sizeof(u64));
notes->src = zalloc(sizeof(*notes->src) + symbol_conf.nr_events * sizeof_sym_hist);
if (notes->src == NULL)
return -1;

Whoops. Thanks for pointing that out.
I've sent a fixed up patch (the check for sizeof_sym_hist wasn't even complete)


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