On Fri, 26 Sep 2025 15:49:04 +0000 Kai Ji <[email protected]> wrote: > Bugzilla ID: 1773 > Cc: [email protected] > > [0] https://bugs.dpdk.org/show_bug.cgi?id=1773 > > Signed-off-by: Kai Ji <[email protected]> > --- > lib/eal/include/rte_common.h | 34 ++++++++++++++++++++++++++++++++++ > 1 file changed, 34 insertions(+) > > diff --git a/lib/eal/include/rte_common.h b/lib/eal/include/rte_common.h > index 9e7d84f929..ddbba083be 100644 > --- a/lib/eal/include/rte_common.h > +++ b/lib/eal/include/rte_common.h > @@ -700,6 +700,40 @@ rte_is_aligned(const void * const __rte_restrict ptr, > const unsigned int align) > return ((uintptr_t)ptr & (align - 1)) == 0; > } > > +/** > + * Constant-time memory inequality comparison. > + * > + * This function compares two memory regions in constant time, making it > + * resistant to timing side-channel attacks. The execution time depends only > + * on the length parameter, not on the actual data values being compared. > + * > + * This is particularly important for cryptographic operations where timing > + * differences could leak information about secret keys, passwords, or other > + * sensitive data. > + * > + * @param a > + * Pointer to the first memory region to compare > + * @param b > + * Pointer to the second memory region to compare > + * @param n > + * Number of bytes to compare > + * @return > + * false if the memory regions are identical, true if they differ > + */ > +static inline bool > +rte_consttime_memneq(const void *a, const void *b, size_t n) > +{ > + const volatile uint8_t *pa = (const volatile uint8_t *)a; > + const volatile uint8_t *pb = (const volatile uint8_t *)b; > + uint8_t result = 0; > + size_t i; > + > + for (i = 0; i < n; i++) > + result |= pa[i] ^ pb[i]; > + > + return result != 0; > +}
New functions usually have to be marked experimental. Since DPDK adopts many things from FreeBSD, perhaps the function should use the same naming conventions. That would mean int rte_consttime_memequal(void *, void *, size_t len); And will also need to update release notes.
