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author | Guy Harris <guy@alum.mit.edu> | 2015-03-02 13:46:29 -0800 |
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committer | Guy Harris <guy@alum.mit.edu> | 2015-03-02 13:52:53 -0800 |
commit | c6f424fb2e9726811330cb66e7887bb9dfd9d8ee (patch) | |
tree | e84cb110d97112efe96e159bbeb90c37812d4b87 | |
parent | 09e9bc198bcabcd08d259094e716e31d39db5256 (diff) | |
download | tcpdump-4.2.tar.gz |
Fix the pointer tests in the non-ndoified TTEST2() macro as well.tcpdump-4.2
-rw-r--r-- | interface.h | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/interface.h b/interface.h index 18668a21..669c00ee 100644 --- a/interface.h +++ b/interface.h @@ -105,9 +105,21 @@ extern int32_t thiszone; /* seconds offset from gmt to local time */ * that "snapend - (l)" underflows. * * The check is for <= rather than < because "l" might be 0. + * + * We cast the pointers to uintptr_t to make sure that the compiler + * doesn't optimize away any of these tests (which it is allowed to + * do, as adding an integer to, or subtracting an integer from, a + * pointer assumes that the pointer is a pointer to an element of an + * array and that the result of the addition or subtraction yields a + * pointer to another member of the array, so that, for example, if + * you subtract a positive integer from a pointer, the result is + * guaranteed to be less than the original pointer value). See + * + * http://www.kb.cert.org/vuls/id/162289 */ -#define TTEST2(var, l) (snapend - (l) <= snapend && \ - (const u_char *)&(var) <= snapend - (l)) +#define TTEST2(var, l) \ + ((uintptr_t)snapend - (l) <= (uintptr_t)snapend && \ + (uintptr_t)&(var) <= (uintptr_t)snapend - (l)) /* True if "var" was captured */ #define TTEST(var) TTEST2(var, sizeof(var)) |